MXPA01007030A - Carbide and oxycarbide based compositions and nanorods - Google Patents

Abstract

Compositions including oxycarbide-based nanorods and/or carbide-based nanorods and/or carbon nanotubes bearing carbides and oxycarbides and methods of making the same are provided. Rigid porous structures including oxycarbide-based nanorods and/or carbide based nanorods and/or carbon nanotubes bearing carbides and oxycarbides and methods of making the same are also provided. The compositions and rigid porous structures of the invention can be used either as catalyst and/or catalyst supports in fluid phase catalytic chemical reactions. Processes for making supported catalyst for selected fluid phase catalytic reactions are also provided. The fluid phase catalytic reactions catalyzed include hydrogenation, hydrodesulfurisation, hydrodenitrogenation, hydrodemetallisation, hydrodeoxigenation, hydrodearomatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation.

Description

COMPOSITIONS AND NANOVARILLAS BASED ON CARBIDE AND OXYCHARB17RO BACKGROUND OF THE INVENTION Field of the Invention The invention relates to compositions based on carbide and oxycarbide-based nanorods, carbide nanotubes including carbide and / or oxycarbide compounds, rigid porous structures including these compositions and methods for producing and using them. More specifically, the invention relates to rigid three-dimensional structures comprising carbon nanotubes containing carbides and oxycarbides, nanorods based on carbides and / or oxycarbons, which have high surface areas and porosities, low gross densities, substantially no micropores, and increased resistance to crushing. The invention also relates to using the compositions of carbide-based nanorods, oxycarbide-based nanorods, carbon nanotubes comprising carbide and oxycarbide compounds and rigid porous structures including these compositions, such as catalysts and catalyst supports, useful for many types of heterogeneous catalytic reactions, which are frequently found in petrochemical and refining processes.

Description of the Related Art Heterogeneous catalytic reactions are widely used in chemical processes, in the petroleum, petrochemical and chemical industries. These reactions are commonly carried out with the reagent (s) and the product (s) in the fluid phase and the catalyst in the solid phase. In heterogeneous catalytic reactions, the reaction occurs at the interface between phases, ie the interface between the fluid phase of the reactant (s) and the product (s) and the solid phase of the supported catalyst. Therefore, the surface properties of a heterogeneous sustained catalyst are significant factors in the effective use of that catalyst. Specifically, the surface area of the active catalyst, as it is sustained and the accessibility of that surface area to the chemo-absorption of reagents and desorption of products, are important. These factors affect the activity of the catalyst, that is, the rate of conversion of reactants into product. The chemical purity of the catalyst and the catalyst support have an important effect on the selectivity of the catalyst, ie the degree to which the catalyst generates a product from among several products and the useful life of the catalyst. In general, the catalytic activity is proportional to the surface area of the catalyst. Therefore, a high specific area is convenient. However, that surface area must be accessible to reagents and products as well as heat flow. The chemo-absorption of a reagent by a catalyst surface is preceded by the diffusion of that reagent through the internal structure of the catalyst. Since the active catalyst compounds are often held in the internal structure of a support, the accessibility of the internal structure of a support material to the reagent (s), the product (s) and the thermal flux, is important. The porosity and pore size distribution of the support structure are measures of that accessibility. The activated carbons and activated carbons used as catalyst supports have a surface area of approximately 1000 square meters per gram and porosities less than one milliliter per gram. However, much of this surface area and porosity as much as 50%, and often more, are associated with micropores, ie, pores with pore diameters of 2 nanometers or less. These pores may be inaccessible due to diffusion limitations. They plug easily and in this way they are deactivated. Thus, high porosity material where the pores are primarily in the ranges of mesopores (> 2 nanometers) or macropores (> 50 nanometers) are more convenient.

It is also important that self-supporting catalysts and supported catalysts do not fracture or undergo frictional attrition or wear during use, because these fragments can be trapped in the reaction stream and then must be separated from the reaction mixture. The cost of replacing worn-out friction catalysts, the cost of separating them from the reaction mixture and the risk of contaminating the product, are all burdens on the process. In other processes, for example when the solid sustained catalyst is filtered from the process stream and recycled to the reaction zone, the fines can clog the filters and interrupt the process. It is also important that a catalyst, at a minimum, reduces its contribution to chemical contamination of the reagent (s) and the product (s). In the case of a catalyst support, even this is more important since the support is a potential source of contamination to both the supporting catalyst and the chemical process. In addition, some catalysts are particularly sensitive to contamination that can already promote undesired competition reactions, ie affect their selectivity, or render the catalyst ineffective, ie "poison" it. Charcoal and graphite or commercial carbons made from petroleum residues, usually contain trace amounts of sulfur or nitrogen as well as metals common to biological systems and may be undesirable for that reason. Since the 1970s, nanofibers or carbon nanotubes have been identified as materials of interest for these applications. Carbon nanotubes exist in a variety of forms and have been prepared through the catalytic decomposition of various carbon-containing gases on metal surfaces. Nanofibers such as fibrils, Bucky tubes and nanotubes are distinguished from continuous carbon fibers, commercially available as reinforcing materials. In contrast to nanofibers, which have proportions of conveniently large, but inevitably finite dimensions, the carbon fibers contain have dimensions proportions (L / D) of at least 104 and often 105 or more. The diameter of continuous fibers is also much larger than that of nanofibers, always being >; 1.0 μ and typically 5 to 7 μ. The patent of the U.S.A. No. 5,576,465 issued to Ledoux et al., Describes a process for isomerizing straight chain hydrocarbons having at least seven carbon atoms using catalysts including molybdenum compounds whose active surface consists of partially oxidized molybdenum carbide to form one or more oxycarbides. Ledoux et al. Describe several ways to obtain an oxycarbide phase in molybdenum carbide. However, their methods require the formation of molybdenum carbides when molybdenum metal gaseous compounds react with charcoal at temperatures between 900 ° C and 1400 ° C. These are intense processes in energy. Furthermore, the carbides of the resulting molybdenum carbides have many similar disadvantages as other catalysts prepared with charcoal. For example, much of the surface area and porosity of the catalyst are associated with micropores and as such, these catalysts are easily plugged and thus deactivated. While activated charcoals and other materials have been used as catalysts in catalyst supports, none to date has had all the necessary qualities of high surface area porosity, pore size distribution, attrition resistance and purity, to drive a variety of select petrochemical and refining processes. For example, as stated above, although these materials have high surface area, much of the surface area is in the form of inaccessible micropores (ie, diameter <2 nm). It would therefore be desirable to provide a family of catalysts and catalyst supports that have high accessible surface area, high porosity, resistance to attrition, are substantially free of micropores, are highly active and selective and do not show significant deactivation after many hours of operation. Mats of nanofibers, assemblies and aggregates have been previously produced to take advantage of an increased surface area per gram that is achieved using fibers with extremely thin diameters. These structures are typically composed of a plurality of nanotubes and intermixed or crosslinked. OBJECTIVES OF THE INVENTION One objective of the present invention is to provide a composition that includes a multiplicity of oxycarbide nanorods having predominantly diameters between 2.0 nm and 100 nm. A further objective of the present invention is to provide another composition that includes a multiplicity of carbide nanoprids comprising oxycarbons. A further objective of the present invention is to provide another composition that includes a multiplicity of carbon nanotubes having diameters predominantly between 2.0 nm and 100 nm, these nanotubes comprise carbides and optionally also oxycarbides.

A further objective of the present invention is to provide another composition that includes a multiplicity of carbon nanotubes having a carbide portion and optionally an oxycarbide portion. A further objective of the present invention is to provide rigid porous structures comprising compositions including a multiplicity of oxycarbide nanorods or a multiplicity of carbide nanorods with or without oxycarbides. A further objective of the present invention is to provide compositions of matter comprising three-dimensional rigid porous structures, which include oxycarbide nanorods, carbide nanorods, carbide nanorods comprising oxycarbons or carbon nanotubes comprising a carbide portion and optionally an oxycarbide portion. A further objective of the present invention is to provide methods for the preparation and use of the rigid porous structures described above. The invention has as an additional objective the provision of improved catalysts, catalyst supports and other compositions of industrial value based on composition including a multiplicity of carbide nanovarillas, oxycarbide nanoprids and / or carbon nanotubes comprising carbides and oxycarbides.

The invention has as an additional objective to provide improved catalysts, catalyst supports and other industrial value compositions based on rigid, three-dimensional porous carbide and / or oxycarbide structures of the invention. An object of the invention is to provide improved catalyst systems, improved catalyst supports and supported or supported catalysts for heterogeneous catalytic reactions, for use in chemical processes in the petroleum, petrochemical and chemical industries. A further objective of the invention is to provide improved methods for preparing supported catalyst and catalyst systems. Another objective of the invention is to improve the economy and reliability of production and use of catalytic systems and supported catalysts. A further objective of the invention is to provide rigid, substantially pure, improved carbide catalyst support of high porosity, activity, selectivity, purity and attrition resistance. The foregoing and other objects and advantages of the invention will be set forth in or apparent from the following description and drawings. SUMMARY OF THE INVENTION The present invention, which addresses the needs of the prior art, provides a composition that includes nanorods containing oxycarbides. Another composition that is provided by the present invention includes carbide-based nanorods that also contain oxycarbonates. Another composition that is provided by the invention relates to carbon nanotubes that contain both carbides and oxycarbons. In one composition, the carbides retain the structure of the original carbon nanotube aggregates. However, a composition including carbide-based nanorods is also provided, where the morphology of carbon nanotube aggregates is not retained. The invention also provides a composition of carbides held in carbon nanotubes wherein only a portion of the carbon nanotubes has been converted to carbide and / or carbide-based nanorods. The present invention also provides rigid porous structures including oxycarbide nanorods and / or carbide nanorods and / or carbon nanotubes containing carbides and oxycarbides. Depending on the morphology of the carbon nanotubes used as carbon sources, the rigid porous structures may have a uniform or non-uniform pore distribution. Extruded from oxycarbide nanorods and / or nanorods based on carbide and / or carbon nanotubes containing oxycarbides and / or carbides, are also provided. The extrudates of the present invention adhere together to form a rigid porous structure. The invention also provides the rigid porous structures and structures of the invention to be used either as catalysts and / or catalyst supports in fluid phase catalytic chemical reactions. The present invention also provides methods for producing nanorolabs based on oxycarbide, novarillas based on carbide containing oxycarbones and carbon nanotubes containing carbides and oxycarbides. Methods to produce rigid porous structures are also provided. Rigid porous structures of carbide nanorods can be formed by treating rigid porous structures of carbon nanotubes with a Q-based compound. Depending on the temperature ranges, the conversion of the carbon nanotubes into carbide-based nanorods can be complete or partial. The rigid porous structure of carbide nanorods and / or carbon nanotubes can be further treated with an oxidizing agent to form oxycarbide nanorods and / or oxycarbides. The rigid porous structures of the invention can also be prepared from carbide-based nanorods and / or aggregate or loose oxycarbide-based by initially forming a suspension in a medium, separating the suspension from the medium and pyrolyzing the suspension to form rigid porous structures. The present invention also provides a process for producing sustained catalysts for catalytic reactions in select fluid phase. Other improvements that the present invention provides compared to the prior art will be identified as a result of the following description that establishes the preferred embodiments of the present invention. The description in no way is intended to limit the scope of the present invention, but rather only to provide an operative example of the presently preferred embodiments. The scope of the present invention will be pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Figure IA is an XRD graph of sample 12 as set forth in Table 1. A hexagonal Mo2C reference XRD pattern is shown immediately below. Figures IB and 1C are SEM micrographs of sample 12 as set forth in Table 1.

Figure 2A is an XRD plot of sample 12 as set forth in Table 1. A hexagonal Mo2C reference XRD pattern is also shown immediately below. Figure 2B is a HRTEM micrograph of sample 12 as set forth in Table 1. Figure 3A is an XRD plot of sample 10 as set forth in Table 1. Reference XRD patterns of hexagonal Mo2C, cubic Mo2C and graphite , are illustrated immediately below. Figure 3B is a HRTEM micrograph of sample 10 as illustrated in Table C. Figure 4 is a thermogravimetric analysis of sample 12 as set forth in Table 1. Figure 5A is a SEM micrograph of SiC extrudates. Figure 5B is an SEM micrograph illustrating micropores between the aggregates of the extrudates shown in Figure 5A. Figure 5C is an SEM micrograph illustrating micropores in the network of interleaved SiC nanorods present in the extrudates shown in Figure 5A. DETAILED DESCRIPTION OF THE INVENTION Definitions The terms "nanotube", "nanofiber" and "fibril" are used interchangeably. Each refers to an elongated hollow structure having a diameter less than 1 miera. The term "nanotube" includes "nanofiber" or "fibril" (which refers to an elongated solid, (for example, angular fibers having edges) structures having a cross section less than 1 miera.The term "nanotube" also includes " tubes of Bucky "and graphitic nanofibers, the graphene planes of which are oriented in a fish skeleton pattern." Graphene "carbon is a form of carbon whose carbon atoms each bind to three other carbon atoms in a layer essentially planar that forms hexagonal fused rings.The layers are platelets of only a few rings in diameter or they can be ribbons with many rings long but only a few rings wide. "Graphical analogue" refers to a structure that is incorporated into a surface graphene "Graffitic" carbon consists of layers that are essentially parallel to each other and not more than 3.6 angstroms apart The term "nanowire" refers to a rod-like structure that has a surface and a substantially solid core with a diameter less than equal to 100 nm and at least 1.0 nm The structure has a dimension ratio between 10 and 500 and a length of up to 50 μ. or of a nano-wand is substantially uniform over the entire length of the nano-wand. A nanoprobe is solid without being hollow with one open end, nor is it hollow with two sealed ends. The term "carbides" refers to well-known compounds of composition QC or Q2 C. In general, Q is chosen from the group consisting of transition metals (groups 3b, 4b, 5b, 6b, 7b, 8 of periods 4, 5, 6 of the Periodic Table) rare earths (lanthanides) and actinides.

More preferably, Q is selected from the group consisting of B, Ti, Nb, Zr, Hf, Si, Al, Mo, V and W. The term also includes crystal structures characterized by X-ray diffraction (XRD) as QC or Q2C by themselves and / or in combinations with Q or C, for example remaining after the synthesis step is substantially complete. Carbides can be detected and characterized by X-ray diffraction (XRD). When, as contemplated within the scope of this invention, the carbides are prepared by carburization of metal oxides or by oxidation of elemental carbon, a certain amount of "non-stoichiometric" carbide may appear, but the diffraction pattern of the carbides true will still be present. Non-stoichiometric metal-rich carbides, such as those that can be formed from a synthesis in which the metal is carburized, are simply missing a few of the carbons that the metal matrix can accept. The non-stoichiometric carbon-rich carbides comprise domains of stoichiometric carbides embedded in the original carbon structure. Once the carbide crystallites are sufficiently large they can be detected by XRD. Carbides also refer to interstitial carbides as defined more specifically in "Structural Inorganic Chemistry" by A.F. Wells, 4th Edition, Clarendon Press, Oxford 1975 and in "The Chemistry of Transition Metal Carbides and Nitrides" (The Chemistry of Transitional Metals and Nitrides), edited by S.T. Oyama, a Blackie Academic &; Professional publication, both of which are incorporated herein by reference as if they were fully established. The term "carbonate-based nano-rod" refers to a predominantly Q-based nano-rod having a diameter greater than 2.0 nm but less than 50 nm, where Q is an element capable of forming a carbide, Q is selected from the group consisting of of B, Ti, Ta, Nb, Zr, Hf, Si, Al, Mo, V, W, and has a ratio of dimensions of 5 to 500. When the carbide nanoprobe has been made by converting the carbon from the nanotube to carbide compounds, then the conversion has been substantially complete. The term "oxycarbon-based nano-rod" refers to a nano-rod based on M, having a substantially uniform diameter greater than 1.0 nm but less than or equal to 100 nm, wherein M is any metal capable of forming an oxycarbide such as Ti, Ta, Nb, Zr, Hf, Mo, V, W, B, Si and Al. It has a size ratio of 5 to 500. Oxycarbons, unlike carbides, are inherently non-stoichiometric. The oxycarbides of the present invention have the formula: MC 0 wherein M is selected from the group consisting of transition metals (groups 3b, 4b, 5b, 6b, 7b, 8 of the periods 4, 5, 6 of the Periodic Table Rare earths (lanthanides) and actinides, and more preferably Ti, Ta, Hf, Nb, Zr, Mo, V, W, Si, Al, B; n and x are chosen to satisfy a known stoichiometry of a carbide of Q, where Q is equal to M; and is less than x and the ratio [y / (x-y)] is at least 0.02 and less than 0.9 and more preferably between 0.05 and 0.50. The term "oxycarbonates" also includes but is not limited to products formed by oxidative treatments of carbides present in connection with carbon nanotubes as a carbon source or in connection with carbide nanovarillas as a source of carbides. Oxycarbons may also include products formed by carburization of metal oxides. The oxycarbides also comprise mixtures of unreacted carbides and oxides, chemosorption oxygen and physiosorption. M is selected from the group consisting of Mo, W, V, Nb, Ta, Ti, Zr, Hf, B. Si and Al. More specifically, the oxycarbides have a total amount of oxygen sufficient to provide at least 25% of at least one monolayer of absorbed oxygen as determined by temperature program desorption (TPD) based on the carbide content of the carbide source. Oxycarbons also refer to compounds of the same name as defined in "The Chemistry of Transition Metal Carbides and Nitrides" (Chemistry of Transitional Metals and Nitrides), edited by S.T. Oyama, to Blackie Academic & Professional publication, incorporated here by reference as it was fully established. Examples of oxycarbons include polycrystalline compounds, wherein M is a metal preferably in two valent states. M can be attached to another metal atom or only to an oxygen or only to a carbon atom. However, M does not bind to either an oxygen atom or a carbon atom. The term "aggregate" refers to a structure of dense microscopic particles. More specifically, the term "set or aggregate" refers to structures that have relatively or substantially uniform physical properties on at least one unidimensional axis and conveniently have relative or substantially uniform physical properties in one or more planes within the set, i.e. they have isotropic physical properties in this plane. The assembly may comprise uniformly dispersed individual interconnected nanotubes or a mass of aggregates of connected nanotubes. In other embodiments, the entire assembly is relative or substantially isotropic with respect to one or more of its physical properties. The physical properties that can be easily measured and by which the uniformity or isotropy is determined, include resistivity and optical density. The term "pore" traditionally refers to an opening or depression in the surface of a catalyst or catalyst support. Catalysts and catalyst supports comprise carbon nanotubes that lack these traditional pores. In contrast, in these materials, the spaces between individual nanotubes behave like pores and the equivalent pore size of aggregates of nanotubes can be measured by conventional methods (porosimetry) of pore size measurement and pore size distribution. By varying the density and structure of aggregates, the equivalent pore size and the pore size distribution can be varied. The term "micropore" refers to a pore having a diameter less than 2 micrometres. The term "mesopore" refers to pores having a cross section greater than 2 nanometers. The term "non-uniform pore structure" refers to a pore structure that occurs when discrete individual nanotubes are distributed in a substantially non-uniform manner with substantially non-uniform spacings between nanobuses. The term "uniform pore structure" refers to a pore structure that occurs when discrete nanotubes or nanofibers form the structure. In these cases, the distribution of individual nanotubes in the particles is substantially uniform with substantially regular spacings between the nanotubes. These spacings (analogous to pores in conventional supports) vary according to the densities of the structures.

The term "bimodal pore structure" refers to a pore structure that occurs when aggregate particles of nanotubes and / or nanorods are joined together. The resulting structure has a two-row architecture comprising a macrostructure of aggregates of nanotubes having macropores between bundles of aggregates of nanotubes and a microstructure of intercalated nanotubes having a pore structure within each individual bundle of aggregated particles. The term "surface area" refers to the total surface area of a substance, which is measured by the BET technique. The term "accessible surface area" refers to that surface area not attributed to micropores (ie, pores having diameters or cross sections less than 2 nm). The term "isotropic" means that all measurements of a physical property within a plane or volume of the structure, regardless of the direction of the measurement, are of a constant value. It is understood that measurements of these non-solid compositions should be taken in a representative sample of the structure, such that the average value of the hollow spaces is taken into account.

The term "internal structure" refers to the internal structure of a set that includes the relative orientation of the fibers, the diversity of and overall average of nanotube orientations, the proximity of the nanotubes to each other, the hollow space or pores created by the interstices and spaces between the fibers and the size, shape, number and orientation of the flow channels or trajectories formed by the connection of the hollow spaces and / or pores. According to another embodiment, the structure may also include features relating to the size, spacing and orientation of aggregated particles that make up the assembly. The term "relative orientation" refers to the orientation of an individual nanotube or aggregate with respect to the others (ie, aligned versus non-aligned). The "diversity of" and "total average" orientations of nanotubes or aggregates refers to the range of orientations of nanotubes within the structure (alignment and orientation with respect to the external surface of the structure). The term "physical property" means an inherent, measurable property of the porous structure, for example surface area, resistivity, fluid flow characteristics, density, porosity, etc. The term "relatively" means that ninety-five percent of the values of the physical property when measured on an axis, or within a plane of or within a volume of the structure, as the case may be, will be within more. or minus 20 percent of an average value. 5 The term "substantially" means that ninety-five percent of the values of physical property when measured on an axis of, or within a plane of, or within a volume of the structure, as the case may be, shall be within plus or minus ten percent of a P 10 average value. The terms "substantially isotropic" or "relatively isotropic" correspond to the ranges of variability in the values of physical properties stated above. 15 The term "predominantly" has the same meaning as the term "substantially". Carbon nanotubes The term nanotubes refers to various tubes or carbon fibers that have very small diameters 20 including fibrils, microfibers or fine fibers, Bucky tubes, etc. These structures provide significant surface area when incorporated into a structure due to their size and shape. Even more, these nanotubes can be made with high purity and uniformity.

Preferably, the nanotube used in the present invention has a diameter of less than 1 miera, preferably less than about 0.5 miera and even more preferably less than 0.1 miera and in particular less than 0.05 miera. Carbon nanotubes can be produced with diameters in the range of 3.5 to 70 nanometers. The nanotubes, Bucky tubes, fibrils and microfibers that are referred to in this application, are distinguished from commercially available continuous carbon fibers as reinforcing materials. In contrast to nanofibers, which have the proportions of suitably large but inevitably finite dimensions, continuous carbon fibers have portions of dimensions (L / D) of at least 104 and often 106 or more. The diameter of continuous fibers is also much larger than that of fibrils, always being >1.0 μm and typically 5 to 7 μm. Continuous carbon fibers are made by the pyrolysis of organic precursor fibers, usually rayon, polyacrylonitrile (PAN) and pitch. In this way, they can include hetero-atoms within their structure. The graphite nature of continuous carbon fibers "as they are produced" varies, but may be subject to a subsequent graphitization stage. Differences in degree of gradation, orientation and crystallinity of graphite planes if present, the potential presence of hetero-atoms and even the absolute difference in substrate diameter, make the experience with continuous fibers as deficient prognosticators of nanofiber chemistry. Carbon nanotubes are vermicular carbon deposits with diameters less than 1.0 μ, preferably less than 0.5 μ, even more preferably less than 0.2 μ and in particular less than 0.05 μ. They exist in a variety of forms and have been prepared through the catalytic decomposition of various gases containing carbon on metal surfaces. These vermicular carbon deposits have been deposited almost since the advent of electron microscopy. Good early research and reference are found with Baker and Harris, Chemistry and Physics of Carbon (Chemistry and Carbon Physics), Waiker and Thrower ed. , Vol. 14, 1978, p. 83 and Rodriguez, N., J. Mater. Research, Vol. 8, p. 3233 (1993), each of which is hereby incorporated by reference (see also, Obelin, A. and Endo, M., J. of Crystal Growth, Cristale Growth Review), Vol. 32 (1976), pp. 335-349, incorporated herein by reference). The patent of the U.S.A. No. 4,663,230 issued to Tennent, herein incorporated by reference, describes carbon nanotubes or fibrils, which are free of continuous thermal carbon coating and have multiple ordered graphitic outer layers that are substantially parallel to the axis of the fibril. As such, they can be characterized in that they have their C axes, the axes are perpendicular to the tangents of the curved graphite layers, substantially perpendicular to their cylindrical axes. In general they have diameters no greater than 0.1 μ and length-to-diameter ratios of at least 5. Conveniently they are substantially free of a continuous thermal carbon coating, i.e. pyrolytically deposited carbon resulting from thermal cracking of gas feed used to prepare it. The invention of Tennent provides access to smaller diameter fibrils, typically 35 to 700 A (0.0035 to 0.070 μ) and to an ordered graphite surface "as developed". Fibrillar carbons with less perfect structures, but also without an outer layer of pyrolytic carbon, have also been developed. The patent of the U.S.A. No. 5,171,560 issued to Tennent et al., Herein incorporated by reference, discloses carbon nanotubes free of thermal overcoating and have graphitic layers substantially parallel to the fibril shafts, such that projection of the layers on the fibril shafts extend by a distance of at least two diameters of fibril. Typically, these fibrils are substantially cylindrical, graphitic nanotubes with substantially constant diameter and comprise graphitic and cylindrical blades whose axes c are substantially perpendicular to their cylindrical axes. They are substantially free of pyrolytically deposited carbon, have a diameter less than 0. Iμ and a length to diameter ratio greater than 5. These fibrils are of primary interest in the invention. When the projection of the graphite layers on the nanotube axis extends for a distance less than two nanotube diameters, the carbon planes of the graphitic nanotube, in cross section, take on the appearance of a fish skeleton. These are called fish skeleton fibrils. Geus, in the U.S. patent. No. 4,855,091, incorporated herein by reference, provides a process for preparing fish skeleton fibrils substantially free of a pyrolytic coating. These carbon nanotubes are also useful in the practice of the invention. According to one embodiment of the invention, oxidized nanofibers are used to form rigid porous assemblies. McCarthy et al., In the U.S. patent application. Serial No. 351,967 filed May 15, 1989, incorporated herein by reference, discloses processes for oxidizing the surface of carbon nanotubes or fibrils that includes contacting the nanotubes with an oxidizing agent that includes sulfuric acid (H2SO4) and potassium chlorate ( KC103) under reaction conditions (eg, time, temperature and pressure) sufficient to oxidize the surface of the fibril. The oxidized nanotubes according to the method of McCarthy et al. Are also oxidized non-uniformly, that is, the carbon atoms are substituted with a mixture of carboxyl, aldehyde, ketone, phenolic and other carbonyl groups. The nanotubes have also been oxidized non-uniformly by treatment with nitric acid. International application PCT / US94 / 10168 describes the formation of oxidized fibrils containing a mixture of functional groups. Hoogenvaad, M.S., and collaborators. ("Metal Catalysts Supported on a Novel Carbon Support " (Metal Catalysts Held in a Carbon Support Novelty), presented at the Sixth International Conference with Scientific Basis for the Preparation of Heterogeneous Catalysts, Brussels, Belgium, September 1994) also found that it is beneficial in the preparation of sustained precious metals of nanotubes, to first oxidize the nanotube surface with acid nitric. This pretreatment with acid is a standard step in the preparation of noble metal catalysts sustained with carbon where, given the usual sources of this carbon, it serves equally to clean the surface of undesirable materials so as to functionalize it. In the published work, McCarthy and Bening (Polymer Preprints ACS Div. Of Polymer Chem. 3_0 (1) 420 (1990)) prepare derivatives of nanotubes or oxidized fibrils in order to demonstrate that the surface is constituted by a variety of oxidized groups. The compounds they prepared, phenylhydrazones, haloaromatic esters, talose salts, etc., were selected because of their analytical usefulness, for example being bright in color, or exhibiting some other strong and easily identified and differentiated signal. These compounds were not isolated and are not of practical significance. The nanotubes can be oxidized using hydrogen peroxide, chlorate, nitric acid - and other convenient reagents. The nanotubes within the structure can also be functionalized as set forth in the U.S. patent application. No. 08 / 352,400, filed on December 8, 1995, by Hoch and Moy et al., Entitled "Functionalized Fibrils" (Functionalized Fibrids), incorporated herein by reference. Carbon nanotubes of a morphology similar to the catalytically developed fibrils or nanotubes described above, have been developed in a high-temperature carbon arc, typical, Nature 354 56 1991, incorporated herein by reference). It is now generally accepted (Weaver, Science ^ 265 1994, here incorporated by reference) that these arc-developed nanofibers have the same morphology as the Tennent fibrils previously developed catalytically. Carbon nanofibers developed with arc are also useful in the invention. Aggregates of Nanotubes and Sets The "unbound" precursor nanotubes can be in the form of discrete nanotubes, aggregates of nanotubes or both. When carbon nanotubes are used, the aggregates when present are generally of the morphologies of bird's nest, combed or red-open filaments. The more the aggregates are "entangled", the more processing will be required to achieve a convenient composition, if high porosity is desired. This means that the selection of combed filament aggregate or open network is more preferable for most applications. However, bird nest aggregates will generally be sufficient. As with all nanoparticles, nanotubes are added in various stages or degrees. The catalytically developed nanotubes produced in accordance with U.S. S.N. 08 / 856,657 filed on May 15, 1997 are formed into aggregates, substantially all of which will pass through a sieve of 700 microns. Approximately 50% by weight of the aggregates pass through a sieve of 300 microns. The size of the aggregates as they were done, of course, can be reduced by several means, but this disintegration becomes increasingly difficult as the aggregates become smaller. The nanotubes can also be prepared as aggregates having various morphologies (as determined by scanning electron microscopy) where they are randomly entangled to form matted balls of nanotubes that resemble bird nests ("BN"); or as aggregates consisting of bundles of carbon nanotubes slightly bent or twisted and have substantially the same relative orientation and have the appearance of combed filament ("CY" = combed yarn), for example the longitudinal axis of each nanotube (despite being bent or individual twists) extend in the same direction as the surrounding nanotubes in the bundles; or as aggregates consisting of straight nanotubes to slightly bent or twisted, which are loosely entangled with each other to form an "open network" structure ("ON" = open net). In open-network structures, the entanglement extension of nanotubes is greater than that observed in combed filament aggregates (where individual nanotubes have substantially the same relative orientation) but less than Ja of a bird's nest. Aggregates CY and ON are more easily dispersed than BN making them useful in composite manufacturing where uniform properties are desired throughout the structure. The morphology of the aggregate is controlled by a selection of catalyst support. Spherical supports develop nanotubes in all directions that lead to the formation of bird nest aggregates. Open-nested aggregates and combed filaments are prepared using supports having one or more cleavable planar surfaces for example an iron or metal catalyst particle containing iron deposited in a support material having one or more easily cleavable surfaces and a surface area of at least 1 square meter per gram. Moy et al., In the patent application of the US. Serial No. 08 / 469,430 entitled "Improved Methods and Catalysts for the Manufacture of Carbon Fibrils" (Methods and Enhanced Catalysts for the Manufacture of Carbon Fibers) filed June 6, 1995, incorporated herein by reference, describes nanotubes prepared as aggregates that have various morphologies (as determined by scanning electron microscopy). Additional details regarding the formation of aggregates of nanofibers or carbon nanotubes can be found in the description of the US patent. No. 5,165,909 granted to Tennent; U.S. Patent No. 5,456,897 issued to Moy et al; the patent application of the US. No. 149,573 of Snyder et al., Filed on January 28, 1988, and PCT Application No. US89 / 00322, filed on January 28, 1989 ("Carbon Fibrils" (Carbon Fibers) WO 89/07163, and Moy. and co-workers, U.S. Patent Application Serial No. 413,837 filed September 28, 1989 and PCT Application No. US90 / 05498, filed September 27, 1990 ("Fibril Aggregates and Method of Making Same") ("Aggregates of Fibrilas and Methods to Produce the Same ") WO 91/05089, and patent application of the U.S.A.

No. 08 / 479,864 issued to Mandeville et al., Filed on June 7, 1995 and the patent application of the US. No. 08 / 329,774 by Benning et al., Filed on October 27, 1984 and the patent application of the US. No. 08 / 284,917, filed on August 2, 1994 and the patent application of the US. No. 07 / 320,564, filed on October 11, 1994 by Moy et al., All of which were granted to the same assignee as the present invention and are incorporated herein by reference. Mats or sets of nanotubes have been prepared by dispersing nanofibers in aqueous or organic medium and then filtering the nanofibers to form a mat or set. The mats have also been prepared by forming a gel or paste of nanotubes in a fluid, for example an organic solvent such as propane and then heating the gel or paste to a temperature above the critical temperature of the medium, removing the supercritical fluid and finally removing the porous mat or stopper resulting from the container, wherein the process has been carried out. See, the US patent. with -Request No. 08 / 428,496 entitled "Three-Dimensional Macroscopic Assemblages of Randomly Oriented Carbon Fibrils and Composites Containing Same" (Three-dimensional Macroscopic Sets of Fibrilas from Carbon Randomly Oriented and Compounds that Contain) by Tennent et al., Here incorporated by reference. Extruded Carbon Nanotubes In a preferred embodiment the rigid porous carbon structures comprise extruded carbon nanotubes. Aggregates of carbon nanotubes treated with an adherent or binder agent are extruded by conventional extrusion methods into extrudates that are pyrolyzed or carbonized to form rigid carbon structures having a bimodal pore structure. The bundles of the carbon nanotubes are substantially intact except that they have been extended (eg by sonication) or partially unraveled to provide a bimodal pore structure. The space between aces is in the range from contact points to approximately 1 miera. Within bundles, spaces between carbon nanotubes are in the range of 10 nm to 30 nm. The resulting rigid bimodal porous structure is substantially free of micropores, has surface areas in the range of about 250 m2 / g to about 400 m2 / g and a crush resistance of approximately 1,406 kg / cm2 (20 psi) for extrudates per diameter of 3,175 mm (1/8 inch). Extruded carbon nanotubes have densities in the range of about 0.5 g / cm3 to about 0.7 g / cm3, which can be controlled by the density of the extrusion paste. The extrudates have liquid absorption volumes of about 0.7 cm3 / g. Adhesion or bonding agents are used to form the paste of carbon nanotubes required for extrusion processes. Useful bonding or binding agents include without limitation, cellulose, carbohydrates, polyethylene, polystyrene, nylon, polyurethane, polyester, polyamides, poly (dimethylsiloxane), phenolic resins and the like. The extrudates that are obtained as described above can also be treated with slightly oxidizing agents such as hydrogen peroxide without affecting the integrity of the porous and rigid carbon structure. Subsequently, rigid porous structures can be impregnated with catalytic particles by ion exchange, generally a preferred method for depositing small size particles. Alternatively, the rigid porous carbon structure can also be impregnated with catalysts by incipient wetting or physical or chemical adsorption. Nanovarillas The term nanovarillas refers to structures type rod that have a substantially solid core, a surface and a diameter greater than 1.0 nm but less than 100 nm. The structure has a ratio of dimensions between 5 and 500 and a length between 2 nm and 50 μ and preferably between 100 nm and 20 μ. The nanorods described are substantially solid, nor are they hollow with one open or hollow ends with two sealed ends. Carbide nanorods Carbide-based nanorods can be prepared by using carbon nanotubes as carbon source. For example, D. Moy and C.M. Niu have prepared carbide nanovarillas or nanofibrils as described in U.S. Patent Application 5. No. 08 / 414,369 incorporated herein by reference as if it were fully established. React gas based on Q with nanofibrilas or carbon nanotubes to form, in situ, nanofibrils or carbide nanovarillas based on solid Q at temperatures substantially lower than 1700 ° C and preferably in the range of approximately 1000 ° C to approximately 1400 ° C, and more preferably approximately 1200 ° C. Gases based on Q were volatile compounds capable of forming carbides. In general, Q is chosen from the group consisting of metals from transition (groups 3b, 4b, 5b, 6b, 7b, 8 of periods 4, 5, 6) rare earths (lanthanides) and actinides. Preferably, Q is selected from the group consisting of B, Ti, Ta, Nb, Zr, Hf, Si, Al, Mo, V and W. We refer to that pseudotopotactic conversion, because even though the crystalline dimensions and orientations of the starting material and the product differ, the cylindrical geometry of the starting nanotube is retained in the final nanowire and the nanorods remain separate and predominantly fused together. The diameters of the resulting nanorods were approximately twice that of the starting nanofibrils or carbon nanotubes (1 nm - lOOnm). Carbide nanorods have also been prepared by reacting carbon nanotubes with volatile metal or non-metal oxide species at temperatures between 500 ° C and 2500 ° C, where the carbon nanotube is considered to act as a template, spatially confining the reaction to the nanotube, according to the methods described in PCT / US 96/09675 by CM Lieber, here incorporated by reference. Carbide nanorods formed by methods wherein the carbon nanotube serves as a template are also useful in the present invention. Because of the ease with which aggregates of fibrils and rigid porous structures can penetrate, volatile Q compounds are usually preferred. Volatile Q precursors are compounds having a vapor pressure of at least 20 torr at reaction temperature. The reaction with the volatile compound Q may or may not be carried out through a non-volatile intermediate. Other methods for preparing carbide nanorods include reductive carburization wherein the carbon nanotubes are reacted with volatile metal oxides based on Q followed by passing a flow of a CH4 / H2 gas mixture at temperatures between 250 ° C and 700 ° C.

In addition to the Q-based metal oxides, volatile Q-based compounds useful in the preparation of Q-based carbide nanovarillas include carbonyls and chlorides such as for example Mo (C0) 6, Mo (V) chloride or W chloride. (VI) 0. In a preferred method for producing carbide nanovarillas useful for the present invention, vapors of a volatile Q-based compound are passed over a bed of carbon nanotube extrudates in a quartz tube, at temperatures from about 700 ° C to about 100 ° C. By controlling the concentration of the compound based on Q, the crystallization of the carbides is limited to the space of the nanotube. In all methods of providing carbide-based nanorods, discussed above, the extent of carbon conversion to carbon nanotubes in carbide nanorods can be controlled by adjusting the concentration of the compound based on Q, the temperature at which the reaction occurs and the duration of exposure of carbon nanotubes to the compound based on volatile Q. The carbon conversion length from the carbon nanotubes is between 40 and 100% and preferably around 95%. The resulting carbide nanorods have an excellent level of purity in the carbide content, a greatly increased surface area and improved mechanical strength. The surface area of the carbide nanovarillas is from 1 to 400 and preferably from 10 to 300 m2 / g. Applications for compositions based on carbide nanorods include catalysts and catalyst support. For example, compositions that include carbide nanovarillas based on molybdenum carbide, tungsten carbide, vanadium carbide, tantalum carbide and niobium carbide, are useful as catalysts in fluid phase catalytic chemical reactions selected from the group consisting of hydrogenation, hydrodesulization, hydrodigenesis, hydrodesmetalization, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. Similarly, nanorods based on aluminum carbide and silicon carbide are especially useful as catalyst supports for conventional catalysts such as platinum and palladium, as well as for other Q-based carbides such as molybdenum carbide, tungsten carbide, vanadium carbide and similar. Oxycarbonate nanorods Nanovarillas based on oxycarbide can be prepared from carbide nanorods. The carbide nanovarillas are subjected to oxidative treatments known in the art. For example, oxidative treatments are described in U.S. Pat. No. 5,576,466 granted to Ledoux, and collaborators; M. Ledoux, and collaborators. European Patent Application No. 0396 475 Al, 1989; C. Pham-Huu, et al., Ind. Eng. Chem. Res. 34, 1107-1113, 1995; E. Church, et al., Journal of Catalysis, 131, 523-544, 1991, incorporated herein by reference as if they were fully established. The above oxidative treatments are applicable to the formation of oxycarbide nanorods as well as the formation of nanotubes and / or nanorods, which comprise an oxycarbide portion in which the cosion of the carbide source is incomplete. Oxycarbon compounds present in an oxycarbide nanopolymer, and also present when the cosion of the carbide source is incomplete, include oxycarbons having a total amount of oxygen sufficient to provide at least 25% of at least one absorbed oxygen monolayer as determined by desorption programmed in temperature (TPD = Temperature Programmed Desorption), based on the carbide content of the carbide source. For example, by subjecting the carbide nanorods to an oxidizing gas stream at temperatures between 30 ° C to 500 ° C, oxycarbide nanorods are produced. Useful oxidant gases include but are not limited to air, oxygen, carbon dioxide, N20, water vapor and mixtures thereof. These gases can be pure or diluted with nitrogen and / or argon. Compositions comprising oxycarbide nanovarillas are useful as catalysts in many petrochemical and refining processes including hydrogenation, hydrodesul fu tion, hydrodesitrogenation, hydrodesmetalization, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. Carbides and Oxicarbides Supported According to another embodiment of the present ition, by adjusting the process parameters, for example, the temperature, the concentration of, and the exposure length of the volatile compound based on Q it is possible to limit the cosion rate of the carbon in the carbon nanotube. In this way, it is possible to provide carbon nanotubes having a carbide portion wherein the location of the carbide portion can be engineered as desired. For example, the carbide portion of the carbon nanotube can be completely located on the surface of the carbon nanotube so that only parts of the surface comprise nanocarbon compounds. It is possible to have the entire surface of the carbon nanotube coated with carbides while the core of the carbon nanotube remains substantially carbon. Furthermore, it is possible to control the surface coverage of carbon nanotubes with carbide compounds from 1% to 99% of the entire surface area. A mode wherein the carbon nanotube comprising carbide covers less than 50% of the surface of the carbon nanotube is preferred. Of course, at low percentages, large areas of the carbon nanotube surface remain uncovered. However, as long as the carbide portion of the carbon nanotube is retained on the surface, the morphology of the carbon nanotube remains substantially the same. Similarly, by careful control of the process parameters, it is possible to cot the carbide portion of the nanotube into a carbide nano-rod, thereby obtaining a hybrid nanotube-nanowire structure. The carbide portion can be located anywhere in the carbon nanotube. Partial cosion of carbide carbon compounds preferably ranges from about 20% to about 85% by weight. When the content of the carbide compounds in the carbon nanotube exceeds 85% by weight, then the carbon nanotubes have been substantially coted into carbide nanorods. Once in possession of the present teachings, a person of ordinary skill in the art can determine as a matter of course and unnecessarily by further ition or undue experimentation such as controlling the rate of cosion of carbon nanotubes into carbide nanorods in order to cot the Carbon from carbon nanotubes incompletely. The embodiment of the ition wherein the carbon nanotubes contain a carbide portion also encompasses supplying the carbide portion of the carbon nanotube in any form now known or subsequently developed. For example, in another method of providing carbide compounds in carbon nanotubes or their aggregates, the metal based on Q or metal compound preferably Mo, W or V, is placed in the carbon nanotubes or aggregates directly and then pyrolysed, leaving behind carbon nanotubes coated with carbide compounds. Still in another method of providing carbide compounds in carbon nanotubes, solutions of Q-based salts, such as for example Mo, W or V salts are dispersed on the carbon nanotubes or their aggregates and then pyrolyzed, again forming compounds of carbide primarily on the surface of carbon nanotubes.

A mode where the carbon nanotube core remains as carbon and the location of metal carbides is limited is quite convenient as a catalytic system. The core of the carbon nanotube acts as a catalyst support or carrier for the metal carbide catalyst. Still in another embodiment of the invention, it is possible to transform the carbon nanotube core into a metal carbide preferably silicon carbide or aluminum carbide at temperatures between 1100 ° C and 1400 ° C. Subsequently, when the silicon carbide nanoprobe is brought into contact with the volatile compound of another metal, for example MoO, a mixed carbide nanoprobe having a silicon carbide (preferably β SiC), core and another portion of carbide is provided. based on Q. When MoO is used for example, the SiC nanoprobe may have a MoC portion which may be an outer layer or a nanorole based on MoC. In this way, the resulting nano-wand is a nano-wafer based on mixed carbide, where part of the nano-wand is based on SiC and another portion is based on MoC. There is also an advantageous presence of molybdenum silicide. The mixed carbide nanotube or nanotube as discussed above are particularly convenient as catalyst carriers or directly as catalysts in high temperature chemical reactions, particularly in the petrochemical field. In still another embodiment of the aforementioned improvement, it is possible to subject the nanotube having a carbide portion to oxidative treatments, such that the carbide portion of the nanotube further comprises an oxycarbide portion. The oxycarbide portion comprises oxycarbide compounds located anywhere in, on, and within the carbon nanotube or carbide nanotube. The oxycarbide compounds can be placed in the nanotube in any form now known or subsequently developed. Similarly, the nanotube having a carbide portion can be exposed to the air or subjected to carburization or any other means to convert the carbide portion of the nanotube partially or completely into a portion of oxycarbide nano-rod. In this way, it is possible to provide a carbon nanotube that is partially still a carbon nanotube, partially a carbide nanoprobe and partially an oxycarbide nanoprobe also referred to as a nanotube carbon nanotube carbon-carbide-oxycarbide. Rigid Porous Carbide and Oxicarbide Structures The invention also relates to rigid porous structures made from carbide nanovarillas, oxycarburo nanorods and supported carbide and oxycarbide carbon nanotubes and methods to produce them. The resulting structures can be used in catalysis, chromatography, filtration systems, electrodes, batteries and the like. The rigid porous structures according to the invention have a highly accessible surface area. That is, the structures have a high surface area that is substantially free of micropores (ie pores having a diameter or cross section less than 2 nm). The invention relates to increasing the mechanical integrity and / or stiffness of porous structures comprising carbon nanotubes and / or interbedded carbide and / or oxycarbonate nanorods. The structures made according to the invention have higher crushing strengths than conventional nanowire or carbon nanotube structures. The present invention provides a method for improving the rigidity of carbon structures by causing nanotubes and / or nanorods to form bonds or to adhere with other nanotubes and / or nanorods at the intersections of nanotubes and / or nanorods. The union can be induced by chemical modification of the surface of the nanotubes to promote union by adding "glue" agents and / or by pyrolysis the nanotubes to cause fusion or union in the points of interconnection. Nanotubes or nanorods can be in the form of discrete nanotubes and / or nanorods or aggregated particles of nanotubes and nanorods. The former result in a structure that has substantially uniform properties. The latter results in a structure having a two-row architecture or strips comprising a total macrostructure comprising aggregated particles of nanotubes and / or nanovarillas bonded together and a microstructure of nanotubes and / or nanorods interspersed within the individual aggregate particles. . According to a modality, discrete nanotubes and / or nanotubes form the structure. In these cases, the distribution of strands of nanorods and / or individual nanotubes in the particles is substantially uniform, with substantially regular spacing between strands. These spacings (analogous to pores in conventional supports) vary according to the densities of the structures that are in the approximate range of 15 nm in the densest particles to an average of 50-60 nm in the lightest ones (for example solid mass) formed from open network aggregates). There are absent cavities or spaces that correspond to micropores (<2 nm) on conventional carbon supports. According to another embodiment, the distribution of individual nanotubes and / or nanorods is substantially uniform, with a substantially non-uniform pore structure. However, there are no cavities or spaces corresponding to micropores that are often present in other catalysts and catalyst supports. These rigid porous materials are superior to the high surface area materials currently available for use in fixed bed reactors, for example. The roughness of the structures, the porosity (both in pore volume and pore structure), and the purity of the carbide nanovarillas and / or nanovarillas of oxycarbides, are significantly improved. Combining these properties with relatively high surface areas provides a unique material with useful characteristics. One embodiment of the invention relates to a rigid porous structure comprising carbide nanovarillas having an accessible surface area greater than about 10 m2 / gm and preferably greater than 50 m2 / gm, substantially free of micropores and having a resistance to crushing greater than approximately .454 kg (1 pound). The structure preferably has a density greater than 0.5 g / cm3 and a porosity greater than 0.8 cm3 / g. Preferably, the structure comprises interconnected, interspersed carbide nanowires and substantially free of micropores. According to one embodiment, the rigid porous structure includes carbide nanovarillas comprising oxycarbide compounds and has an accessible surface area greater than about 10 m2 / gm, and preferably greater than 5u m2 / gm, is substantially free of micropores and has a crush resistance greater than about .454 kg (1 pound) and a density greater than 0.5 g / cm3 and a porosity greater than 0.8 cm3 / g. According to another embodiment, the rigid porous structure includes oxycarbide nanowires having an accessible surface area greater than about 10 m2 / gm, and preferably greater than 50 m 2 / gm, being substantially free of micropores with a greater crush resistance. that approximately .454 kg (1 lb.) a density greater than 0.5 g / cm3 and a porosity greater than 0.8 cm3 / g. According to another additional embodiment, the rigid porous structure includes carbon nanotubes comprising a portion of carbide. The location of the carbide portion can be on the surface of the carbon nanotube or any site in, on or on the carbon nanotube, or the carbide portion can be converted into a carbide nanoprobe that forms a hybrid of nanotube-carbide nanotube of carbon. However, the catalytic effectiveness of these rigid porous structures is not affected by the carbide portion in the resulting compounds. These rigid porous structures have accessible surface area greater than about 10 m2 / gm and preferably that 50 m2 / gm, is substantially free of micropores, has a crush resistance greater than about .454 kb (1 pound), a greater density than 0.5g / cm3 and a porosity greater than 0.8 cm3 / g. In another related embodiment, the rigid porous structure includes carbon nanotubes having a carbide portion and also an oxycarbide portion. The location of the oxycarbide portion can be on the surface of the carbide portion or anywhere on, in, or within the carbide portion. Under certain conditions of oxidative treatment, it is possible to convert a portion of the carbide nanovarilla part of the carbon nanotube nanotube carbon-carbide into an oxycarbide. The rigid porous structure incorporates the nanotube-nanopubber carbon-carbide-oxycarbide hybrids has an accessible surface area greater than about 10 m2 / gm, is substantially free of micropores, has a crush resistance greater than about .454 kb (1 pound) ), a density greater than 0.5 g / cm3 and a porosity greater than 0.8 cm3 / g. According to one embodiment, the rigid support structures described above comprise nanotubes and / or nanorods. They are evenly and regularly distributed through the rigid structures. That is, each structure is a rigid and uniform set of nanotubes and / or nanorods. The structures comprise substantially uniform routes and spacings between nanotubes and / or nanorods. The routes or spacings are uniform since each has substantially the same cross section and are spaced substantially evenly. Preferably, the average distance between nanotubes and / or nanorods is less than about 0.03 miera and greater than about 0.005 miera. The average distance can vary depending on the density of the structure. According to another embodiment, the rigid porous structures described above comprise nanotubes and / or nanorods that are distributed non-uniformly and non-evenly through the rigid structures.

The rigid structures comprise routes and substantially non-uniform spacings between the nanorods. The routes and spacings have a non-uniform cross-section and are spaced substantially non-evenly. The average distance between nanotubes and / or nanorods varies between 0.0005 miera and 0.03 miera. The average distances between nanotubes and / or nanorods can vary depending on the density of the structure. According to another embodiment, the rigid porous structure comprises nanotubes and / or nanorods in the form of aggregated particles of nanotubes and / or nanotubes interconnected to form the rigid structures. These rigid structures comprise larger aggregate spacings between the interconnected aggregate particles and spacing of smaller nanotubes and / or nanorods between the nanotubes and / or individual nanorods within the aggregate particles. Preferably, the largest average distance between the individual aggregates is less than about 0.1 miera and greater than about 0.001 miera. The aggregated particles can include for example particles of randomly matted balls of nanotubes and / or nanorods, which resemble bird nests and / or bundles of nanotubes and / or nanorods whose central axes are generally aligned parallel to each other.

Another aspect of the invention relates to the ability to provide porous rigid particles or nodules of a specified size dimension. For example, porous particles or nodules of a size suitable for use in a fluidized packed bed. The method involves preparing a plurality of aggregates of nanotubes and / or nanorods to fuse or glue the aggregates or nanotubes and / or nanorods at their intersections, to form a large solid mass in rigid volume and to dimension the solid mass into pieces of high-area particles. rigid porous surfaces, which have a suitable size for the desired use, for example to a suitable particle size to form a packed bed. General Methods to Produce Rigid Porous Structures The rigid porous structures described above are formed by causing nanotubes and / or nanorods to form bonds or adhere to other nanofibers at fiber intersections. Bonding can be induced by chemical modification of the surface of the nanofibers to promote binding, by adding "glue" agents and / or pyrolyzing the nanofibers to cause fusion or bonding at the interconnection points. The patent application of the U.S.A. 08 / 857,383 filed May 15, 1997, incorporated herein by reference, discloses processes for forming rigid porous structures from nanofibers or carbon nanotubes. These processes or procedures are equally applicable to forming rigid porous structures that include aggregates of discrete unstructured nanotubes or nanotubes comprising carbides and in another embodiment also oxycarbonates, wherein the morphology of the carbon nanotube has been substantially conserved. These methods are also applicable to forming rigid porous structures comprising nanovarillas of carbide or oxycarbide, unstructured or as aggregates. Additionally, these methods are also applicable to form rigid porous structures comprising hybrids of nanotubes-carbon-carbon nanorods and / or nanotubes-carbon nanoroblasts -carbide-oxycarbide. In several other embodiments rigid porous structures comprise carbide nanovarillas are prepared by contacting a rigid porous carbon structure made of carbon nanotubes with volatile Q-based compounds under conditions sufficient to convert all carbon or only part of the carbon in the carbon nanotubes in compounds based on carbide. High-porosity, rigid structures can be formed from regular nanotube aggregates or nanotubes, either with or without modified nanofibers on surfaces (ie, surface-oxidized nanotubes). Oxidized surface nanotubes can be interlaced according to the methods described in the U.S. patent application. No. 08/856, 657 filed May 15, 1997 and in the U.S. patent application. No. 08 / 857,383 also filed May 15, 1997, both incorporated herein by reference and then carbonized to form a rigid porous carbon structure having a uniform pore structure, substantially free of micropores. Preferred Methods for Producing Rigid Carbide-Based Porous Structures There are many methods for preparing rigid porous structures comprising carbide nanovarillas. In one embodiment, the rigid porous carbon structures prepared as described above, are contacted with Q-based compounds under conditions of temperature and pressure sufficient to convert the carbon nanotubes of the rigid porous carbon structure to carbide nanovarillas. The location of the carbide portion of the carbon nanotubes of the rigid porous carbide structure can be on the surface of the carbon nanotube or any site in, on or within the carbon nanotube, or when the conversion is complete then the entire nanotube carbon is transformed into a substantially solid carbon nanorod. Once in possession of the present teachings, a person of ordinary skill in the art can determine as a matter of course and without necessity by further invention or undue experimentation, such as controlling the rate of conversion of carbon nanotubes present in the rigid porous carbon structure. in a structure based on rigid porous carbide comprising carbon nanotubes with a carbide portion that can vary on site in the carbon nanotube and in an amount of from about 20% to about 85%, preferably in excess of 85% by weight. The rigid porous structures based on carbide of the present invention have highly accessible surface areas between 10 m2 / gm and 100 m2 / gm and are substantially free of micropores. These structures have increased mechanical integrity and attrition resistance, by comparison with individual carbide-based nanorods. Rigid porous structures based on carbide have a density greater than 0.5 g / cm3 and a porosity greater than 0.8 cm3 / g. The structure has at least two dimensions of at least 10 microns and no larger than 2 cm. Depending on the pore structure of the starting rigid porous carbon structure, the porous structure of the rigid porous structure based on carbide can be uniform, non-uniform or bimodal. When the rigid porous structure is uniform, the average distance between the carbide-based nanorods is less than 0.03 miera and greater than 0.005 miera. In another embodiment, the rigid porous structure comprises carbide-based nanorods, in the form of interconnected aggregate particles wherein the distance between individual aggregates is in the range from the point of contact to 1 μ. When the rigid porous structures of carbide-based nanorods are formed from rigid porous carbon structures comprising aggregates of nanotubes, the structure has aggregate spacings between particles of interconnected aggregates and spacings of carbide nanorods between nanorods within the aggregated particles. As a result, the rigid porous structure has a bimodal pore distribution. One embodiment of the invention relates to rigid porous structures comprising extrudates of aggregate particles of carbide nanorods, wherein the carbide nanorods are bonded or bonded together with binding agents such as cellulose, carbohydrates, polyethylene, polystyrene, nylon , polyurethane, polyester, polyamides, poly (dimethylsiloxane) and phenolic resins. Without being bound by theory, it is considered that the conversion of a rigid porous carbon structure to a rigid porous structure based on carbide, either completely or partially, is achieved in a pseudo-topotactic form as previously discussed. Preferred Methods for Producing Rigid Porous Structures Based on Oxicarbide There are many methods for preparing rigid porous structures comprising nanowires and / or oxycarbide nanotubes, which comprise a carbide portion and in addition an oxycarbide portion. In one embodiment, the rigid porous structures based on carbide are subjected to oxidative treatments as described in the art and in the U.S. patent. 5,576,466 issued to Ledoux et al., Issued November 13, 1996. In another embodiment, the rigid porous structure comprises carbon nanotubes having an oxycarbide portion and / or a carbide portion, prepared by subjecting them to oxidative treatments described in the art, rigid porous carbon structures that have been partially converted to carbide nanovarillas. In another embodiment, discrete carbide nanovarillas are subjected to oxidative treatments and then assembled into rigid porous structures according to methods similar to those described in the U.S. patent application. No. 08 / 857,383 filed May 15, 1997 incorporated herein by reference. Still in another embodiment, discrete carbon nanotubes or aggregate of carbon nanotubes, which have been partially converted to carbide nanorods, are also subjected to oxidative treatments and then assembled into rigid porous structures according to methods described in the patent application of the USA No. 08 / 857,383 filed May 15, 1997. Catalytic Compositions Carbide and / or oxycarbide nanovarillas and nanotubes having carbide and / or oxycarbide portions of the invention, have superior specific surface areas compared to carbide and oxycarbide catalysts previously illustrated in the art. As a result, they are especially useful in the preparation of self-supported catalysts and as catalyst supports in the preparation of supported catalysts. The self-supported catalysts of the invention include catalytic compositions comprising nanotubes and / or nanorods and rigid porous structures comprising the same. Self-supported catalysts of the invention constitute the active catalyst compound and can be used without any additional physical support to catalyze numerous heterogeneous reactions as described more specifically herein. The supported catalyst of the invention comprises a support that includes a rigid porous structure of nanofibers and / or nanorods and a catalytically effective amount of a supported catalyst therein. The unique high macroporosity of the carbon nanotube structures, the result of their macroscopic morphology, greatly facilitates the diffusion of reagents and products and the flow of heat in and out of the self-supported catalysts. This unique porosity results from random entanglement or intercalation of nanotubes and / or nanorods that generate a volume of internal voids not usually high, comprising primarily macropores in a dynamic rather than a static state. The sustained separability of the fluid phase and lower losses of catalyst as fines, also improves the process performance and economy. Other advantages of nanotube and / or nanorod structures as self-sustaining catalysts include high purity, improved catalyst loading capacity and chemical resistance to acids and bases. As a self-supporting catalyst, carbon nanotube and / or carbon nanotube aggregates provide superior chemical and physical properties in porosity, surface area, separability and purity.

The self-supported catalysts made of nanotubes and / or nanovarillas have a high volume of internal voids that improves the problem of clogging found in various processes. Furthermore, the preponderance of large pores avoids the problems often encountered in reactions limited by mass transfer or diffusion. The high porosities ensure a significantly increased catalyst life. One embodiment of the invention relates to a self-supporting catalyst which is a catalytic composition comprising carbide-based nanorods, with a diameter between at least 1.0 nm and less than 100 nm, and preferably between 3.5 nm and 20 nm. Carbide-based nanorods have been prepared from carbon nanotubes that have been substantially converted into carbide nanorods. In the catalytic composition of this embodiment, the carbide nanorods substantially retain the structure of the original carbon nanotubes. In this way, the carbide nanotubes can have a uniform, non-uniform or bimodal porous structure. These catalyst compositions can be used as catalysts to catalyze reactions such as hydrogenation, hydrodesulfurization, hydrodesnitrogenation, hydrodemetalation, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. Catalytic Compositions Supported in Carbide and Oxicarbide Nanopolymer Aggregates Depending on the application, the rigid porous structures of the invention can be employed as both self-supporting catalysts and catalyst supports. As is true of catalysts comprising regular nanotubes and / or nanorods, catalysts and catalyst supports comprising the rigid porous structures of the invention have unique properties. They are exceptionally mesoporous and macroporous. They are also pure and resistant to friction, compression and shear and consequently can be separated from a fluid phase reaction medium over a long service life. The increased rigidity of the rigid porous structures of the present invention allows catalysts and catalyst supports comprising the structures to be used in fixed bed catalytic reactions. A package contains the rigid structures sizing or dimensioning can be formed and a fluid or gas is passed through the packaging without significantly altering the shape and porosity of the packaging, since the rigid structures are hard and resist compression.

Rigid structures formed from aggregates of nanorods, preferably nanorods based on aluminum carbide and silicon carbide, are particularly preferred structures to be used as catalyst supports. The combination of properties offered by nanowire structures is unique. There are no known catalyst supports that combine such high porosity, high accessible surface area and resistance to attrition. The combination of properties offered by the nanovariella structures is advantageous in any catalyst system susceptible to the use of a carbide catalyst support. The multiple nanorods that make up a nanorod structure provide a large number of binding sites where the catalyst particles can be linked to multiple nanorods in the nanorod structures. This provides a catalyst support that more sustainably supports the supported catalyst. In addition, nanowire structures allow high catalyst loads per unit weight of nanowire. However, catalyst loads which are generally greater than 0.01 weight percent and preferably greater than 0.1, but generally less than 5 weight% based on the total weight of the supported catalyst. Usually, catalyst loads greater than 5% by weight are not useful, however catalyst loads greater than 5% by weight of active catalyst based on the total weight of the supported catalyst, are easily within the scope of the invention, that is to say loads exceeding 100 weight percent based on the weight of the support of the invention, due to the porosity of nanowire structures and other factors discussed herein. Suitable hydrogenation catalysts are the platinum group (ruthenium, osmium, rhodium, iridium, palladium and platinum or a mixture thereof) and preferably, palladium and platinum or a mixture thereof. Group VII metals including especially iron, nickel and cobalt are also attractive hydrogenation catalysts. Oxidation catalysts (including partial oxidation) can also be supported on nanotubes and carbide and oxycarbide nanotube structures. Suitable metal oxidation catalysts include, not only members of the group platinum group listed above, but also, silver and metals of group VIII. Oxidation catalysts also include metal salts known in the art, including salts of vanadium, tellurium, manganese, chromium, copper, molybdenum and mixtures thereof, as described more specifically in "Heterogeneous Catalytic Reactions Involving Molecular Oxygen" (Heterogeneous Catalytic Reactions Involve Molecular Oxygen) by Golodets, GI &; OSS, JRH, Studies in Surface Science, 15, Elsevier Press, NYC 1983. Active catalysts include other carbide compounds such as Ti, Ta, Hf, Nb, Zr, M, or V carbides. and W. These supported carbides are particularly useful for hydrogenation, hydrodesulfurization, hydrodesnitrogenation, hydrodesmetalization, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. Due to its high purity, aggregates of carbide nanorods exhibit high resistance to attack by acids and bases. This feature is advantageous since a route to regenerate catalysts is regeneration with an acid or a base. Regeneration processes employing strong acids or strong bases can be employed. This chemical resistance also allows the carbide supports of the invention to be used in very corrosive environments. The supported catalysts are made by supporting a catalytically effective amount of catalyst in the rigid nanowire structure. The term "in the nanotube and / or nanovarilla structure" includes, without limitation, in, on and within the structure and in the nanotubes and / or nanorods thereof. The aforementioned terms can be used interchangeably. The catalyst can be incorporated into the nanotube and / or nanotube or aggregates before the rigid structure is formed, while the rigid structure is formed (ie, it is added to the dispersion medium) or after the rigid structure is formed. Methods for preparing heterogeneous supported catalysts of the invention include adsorption, incipient moisture impregnation and precipitation. Supported catalysts can be prepared either by incorporating the catalyst onto the aggregate support or by forming in itself and the catalyst can now be active before it is placed in the aggregate or activated in you. The catalyst, such as a coordination complex of a catalytic transition metal, such as palladium, rhodium or platinum, and a ligand such as phosphine, can be adsorbed by forming a slurry of the nanorods in a solution of the catalyst or catalyst precursor by an appropriate time for the desired load. These and other methods can be used to form the catalyst supports. A more detailed description of convenient methods for producing catalyst supports using nanotube structures is set forth in US patent application. Serial No. 08 / 857,383 by Moy et al., Entitled "Rigid Porous Carbon Structures, Methods of Making, Methods of Using and Products Containing Same" ("Rigid Porous Carbon Structures, Methods to Produce, Methods to Use and Products that They contain the same ") presented on May 15, 1997, here incorporated by reference. Preferred Catalytic Composition and Their Uses One embodiment of the invention relates to a catalyst comprising a composition that includes a multiplicity of nanovarillas based on oxycarbide. Each nanovarilla substantially has uniform diameters between 3.5 nm and 20 nm. As previously described, the oxycarbide-based nanorods have a substantially solid core, form a polycrystalline solid substantially, and the individual nanorods are predominantly not fused. Another embodiment refers to a catalyst comprising a rigid porous structure that includes oxycarbide-based nanorods as described above. Each catalyst composition can be used as a catalyst in a fluid phase reaction selected from the group consisting of hydrogenation, hydrodesulfurization, hydrodesnitrogenation, hydrodesmetalization, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. Another embodiment of the invention relates to a catalyst comprising a composition that includes a multiplicity of nanovarillas based on Q, wherein Q is selected from the group consisting of B, Si, Al, Ti, Ta, Nb, Zr, Hf, M or, V and W. The resulting carbide nanorods can be distributed unevenly, uniformly or they can be in the form of interconnected aggregate particles. In a related embodiment, the catalyst comprises a rigid porous structure based on the Q-based nanorods described above, which have been formed into extrudates and connected by bonding agents or glue or in any other form sufficient to form the rigid porous structure. Each catalytic composition discussed immediately above can be used as a catalyst in a fluid phase reaction selected from the group consisting of hydrogenation, hydrodesulfurization, hydrodesnitrogenation, hydrodemetalation, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation.

Another embodiment refers to a catalyst comprising a composition that includes a multiplicity of carbide-based nanorods, which further comprises oxycarbide compounds anywhere, placed on, in or in the nanoprobe, preferably on the surface. In a related embodiment the catalyst comprises a rigid porous structure including carbide-based nanorods comprising oxycarbons that have been formed into extrudates connected in the rigid porous structure by adhesive or glue agents or in any other form sufficient to constitute the rigid porous structure . Each catalytic composition discussed immediately above can be used as a catalyst in a fluid phase reaction selected from the group consisting of hydrogenation, hydrodesulfurization, hydrodesnitrogenation, hydrodemetalisation, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. Another embodiment refers to a catalyst comprising a composition including a multiplicity of carbon nanotubes having substantially uniform diameters. In this embodiment, carbon nanotubes comprise carbide compounds at any point on, in or within the nanotubes, but preferably on the surface of the nanotubes. In yet another related embodiment, the carbon nanotubes additionally comprise oxycarbide compounds on, in or within the nanotubes, but preferably on the surface as more specifically described in the "Supported Carbides and Oxicarbals" section of the specification. In these embodiments, the nanotube morphology is substantially retained. In a related embodiment the catalyst comprises a rigid porous structure including carbon nanotubes comprising carbide compounds and in another embodiment, also oxycarbide compounds as described above. Each rigid porous structure is useful as a catalyst in a fluid phase reaction to catalyze a reaction selected from the group consisting of hydrogenation, hydrodesulfurization, hydrogen or hydrogenating, hydrodesmetalization, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. In another embodiment, the catalyst composition includes a multiplicity of carbon nanotubes having a carbide portion that has been converted to a carbide nanoprobe that forms a hybrid nanotube-nanowire structure. In another related embodiment, the catalyst composition includes a multiplicity of carbon nanotubes that have a portion of carbide nanovarilla and in addition also a portion of oxycarbide that has been converted to an oxycarbide nanovarilla. In still other related embodiments, the above carbon nanotubes can be included in rigid porous structures, where the carbon nanotubes are formed into extruded and / or otherwise formed to form rigid porous structures. The catalytic compositions are useful as catalysts in fluid phase reaction selected from the group consisting of hydrogenation, hydrodesulfurization, hydrodesnitrogenation, hydrodemetalation, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. EXAMPLES The invention is further described in the following examples. The examples are illustrative of some of the products and methods for constituting or producing them that fall within the scope of the present invention. Of course, they will not be considered in any way restrictive of the scope of the invention.

Numerous changes and modifications can be made with respect to the invention. The materials used in the previous examples are readily available commercially. In all the experiments that follow the carbon source is provided by aggregates of carbon nanotubes as manufactured by Hyperion Catalysis International of Cambridge, Mass. The aggregates of carbon nanotubes were of the cotton candy type ("CC") also known as combed filament ("CY"), as described in the section titled "Aggregates and Nanotube Sets" previously. EXAMPLE 1 Preparation of Molybdenum Carbide Precursors by Impregnation of Carbon Nanotube Aggregates with Molybdenum Acetyl Acetonate Five grams of CC aggregate dust samples having porosity of 6.5 cc / gm, were impregnated by the incipient humidity with 35 cc of an ethanol solution, which contains the correct amount of Mo02 (C5H702) 2 or molybdenum acetyl acetonate (here referred to as Moacac) necessary for the desired charge ratio of atoms C: Mo. The resulting mixture is dried at 110 ° C in complete vacuum for 18 hours during which the Mo precursor is decomposed into a mixture of molybdenum suboxides, generally designated Mo03_x, where x is 0 or 1. The sample is separated for conversion to carbide catalysts by careful calcination under an inert atmosphere as described in Examples 5, 6 or 7, previously. EXAMPLE 2 Preparation of Molybdenum Carbide Precursors by Impregnation of Carbon Nanotube Aggregates with Ammonium Molybdate A procedure similar to that used in Example 1 above was followed except that the impregnation solutions were aqueous solutions containing the correct amount of water. heptamolybdate ammonium tetrahydrate or (NH4) 6Mo7024.4H20 herein referred to as ammonium molybdate required for the charge of C: Mo atom ratio desired. The resulting mixtures were dried at 225 ° C under complete vacuum for 18 hours during which the heptamolybdate compound was decomposed in Mo03. The sample was separated for conversion into carbide catalysts by careful calcination under an inert atmosphere as described more particularly in Examples 5, 6 and 7, present. EXAMPLE 3 Preparation of Molybdenum Carbide Extruded Precursors by Impregnation with Molybdenum Acetyl Acetonate or Ammonium Molybdate Aggregates type CC or CY were oxidized with nitric acid, as described in U.S. patent application. Serial No. 08 / 352,400 filed on December 8, 1994 with the title "Functionalized Nanotubes" (to form oxidized CC aggregates having an acid titre of approximately 0.6 mg / g). Five grams of the oxidized CC type aggregates of carbon nanotubes were mixed either with an ethanol solution of Moacac or an aqueous solution of heptamolybdate ammonium tetrahydrate, each solution containing the correct amount of compound Mo needed for the charge C : Desired Mo Mixing is achieved by kneading in a Braybender kneader until the paste has a homogeneous consistency. The excess solvent was removed from the kneaded sample by evaporation until a solids content of about 8 to about 10% by weight was obtained. The material was then extruded when using a pneumatic gun extruder. The extrudates had an approximate diameter of 3,175 mm (1/8 inch) and several centimeters in length. The extrudates were then dried at 200 ° C in the air for 18 hours during which some shrinkage occurred. The dry extrudates were then broken into pieces of approximately 1.5875 x 6.35 mm (1/16 by 1/4 inch), which were separated for conversion into carbide catalysts by careful calcination as described in Examples 5, 6 and 7, present. EXAMPLE 4 Preparation of Molybdenum Carbide Precursor When Mixing Carbon Nanotube Aggregates with Ammonium Molybdate or Molybdenum Oxide As developed CC or CY aggregates, they were oxidized with nitric acid as described in Example 3 to form oxidized CC aggregates which they have an acid titre of approximately 0.6 mg / g. Five grams of oxidized CC type aggregates of carbon nanotubes were physically mixed with the correct amount of either ammonium tetrahydrate heptamolybdate or Mo03 necessary for the desired C: Mo atom ratio when kneading the sample in a mortar and pestle. A small amount of wetting agent such as water or ethylene glycol is added periodically to keep dust from the carbon nanotube powder under control and to facilitate contact between the molybdenum precursor particles and the carbon nanotube aggregates. After the mixture was kneaded to a homogenous thick paste, the excess solvent was removed by slight heating while continuing to knead the sample. The mixture is then dried at 200 ° C for 14 hours in the air and set aside for carbide conversion by careful calcination as described in Examples 5, 6 and 7 present. EXAMPLE 5 Calcination of Molybdenum Carbide Precursors at 600 ° C or 625 ° C Heavy samples of molybdenum carbide precursors were loaded into porcelain cans which were then placed horizontally in a 2.54 cm quartz tube (1 inch) . The tube and can structure is placed in a high temperature oven equipped with a programmable temperature controller and a movable thermocouple. The thermocouple was placed directly in contact with the end of the boat. The sample was heated under a slow flow, ie several standard cc / minute argon at a heating rate of 5 ° C / min at 200 ° C and subsequently at 1 ° C / min at the final temperature of 600 ° C. or 625 ° C. The sample was kept at this temperature for 18 hours. Since pure Mo2C reacts violently with atmospheric oxygen, after cooling in argon at room temperature, the samples were passivated by passing 3% 02 / Ar over them by 1 hour . EXAMPLE 6 Calcination of Carbon Precursors Molybdenum Carbide at 800 ° C The same procedure as described in Example 5 above at 600 ° C was followed. The samples were then kept at 600 ° C for one hour. Subsequently, the heating was resumed at the same speed of 1 ° C / min at 800 ° C and maintained that temperature for another 3 hours. After cooling in argon, the samples were passivated using 3% 02 / Ar. EXAMPLE 7 Calcination of Carbide Precursors Carbide Molybdenum at 1000 ° C The same procedure described in Example 6 above was followed up to 800 ° C, at which temperature the samples were maintained for 1 hour. Subsequently, the heating of the samples was resumed at the speed of 1 ° C / min to 1000 ° C, where the temperature was maintained for 0.5 hour. After cooling in argon, the samples were passivated using 3% 02 / Ar. Results of Examples 1-7 Unsupported carbide nanorods and carbide nanoparticles supported on carbon nanotubes were prepared according to Examples 1 to 7 above. Table 1 below summarizes the experimental conditions and XRD results for the selected experiments.

TABLE 1. SUMMARY OF RESULTS FOR MOLYBDENUM CARBIDE PREPARATIONS 2Mo03 + 7C? Mo2C + 6C0 Initial weight loss SAMPLE METHOD T ° C C; M? (theory) PHASES. XRD 1 Moacac (s) b 600 4 (94) e 27 (44) C, Mo02.Mo2C. { hex) 2 Mo03 (s) to 800 35 (38) e 23 (35) C, Mo2C (cube) 3 Mo03 (s) to 800 40 (34) e n C, Mo2C (hex) 4 oacac (s) b 800 10 { 85) e 31 (32) C, Mo2C (hex) 5 Moacac (s) b 800 20 (57) e 27 (22) Mo2C (hex / cub) Mo 6 Mo03 (s) b 1000 10 (85) e 41 (32) Mo2C (hex) .Mo 7 M0O3 (s) 1000 20 (57) e 27 (22) Mo2C (hex / cub), Mo 8 Mo03 (s) 1000 10 { 85) e 38 (32) C, Mo2C (hex) 9 Mo03 (s) 625 30 (43) e 20 (17) C, Mo2C (hex / cub) Mo03 (s) b 625 20 (57) e 27 (22) C, Mo2C (hex), Mob2 11 Mo03 (s) b 1000 50 (28) '12 (11) C, Mo2C (hex / cub) 12 Mo03 (s) c 800 3.5 (100) '55 (55) Mo2C (hex / cub) Powder impregnated with aggregates of carbon nanotubes b Extruded impregnated with aggregates of carbon nanotubes c Powder of aggregates of carbon nanotubes physically mixed with precursor Mo e Mo2C load calculated on final calcined product considering complete conversion of Mo precursor in Mo2C The chemical reaction followed by all the experiments summarized in Table 1 above is set at the top. In the method column, there is a list of molybdenum precursors that were converted to Mo2C by reaction with carbon nanotubes. Moacac refers to molybdenyl acetylacetonate and Mo03 refers to molybdenum trioxide. "(s)" refers to the solid phase of the molybdenum precursor. Superscripts a, b and c refer to methods of dispersing the reagents as described in Examples 2, 3 and 4, respectively. T ° C refers to the final calcination temperature of the reaction temperature cycle. "C: Initial Mo" refers to the atomic ratio of C: Mo in the original reaction mixture before conversion to a carbide compound. For example, the stoichiometric atomic ratio to produce pure carbide without excess C or Mo, ie pure Mo2C is 3.5. The number that follows in parentheses is the calculated load of Mo2C contained in the resulting materials. "Weight loss (theoretical)" refers to the theoretical weight loss according to the equation in the upper part of Table 1. "XRD phases" show the compounds found in the X-ray diffraction analysis (XRD) ). Mo2C exists in two distinct crystallographic phases, hexagonal and cubic. Table 2 below summarizes the XRD results for the samples in Table 1. TABLE 2. XRD RESULTS SUMMARY Mo2C Mo2C Mo, 0 Sample (hex) (cubic) MoC > 100 nm 1 15"" 20 nm Minor Component 2 5 ~ 8 nm 3 5 ~ 8 nm 4 10 '"15 nm 5 15'" 20 nm ~ 15 nm 6 20 nm 7 36 '"38 nm 8 8 ~ 10 nm 8 ~ 10 nm 9 18 nm Minor Component 20 '"25 nm 5 ~ 8 nm 11 35 nm 12 26 nm Table 2 summarizes the XRD results for the experiments included in Table 1, identifies the compounds produced, the phases present and the average particle size calculated for the different The average particle size is an average volume-derived size, such that the value of a large particle counts more strongly than several medium particles and much more than the volume of many small particles.This is a well-known conventional procedure by those familiar with the XRD methods Discussion of Results of Examples 1-7 A. Unsupported Nanoparticles and Nanoprints Samples 1 and 12 provide the clearest evidence of the formation of nanopolymers and nanoparticles of Mo2C auto- These were obtained- by reacting stoichiometric or quasi-stoichiometric mixtures of Mo03 and carbon nanotubes, either as powders or as extrusions. Two, product identification and morphologies were obtained by SEM, HRTEM and XRD. In Example 1, with approximately 15% C excess, the major product was identified by XRD as the hexagonal phase of Mo2C. Mo02 and graphite carbon are seen as minor components. SEM showed the presence of both nanorods (diameter "10-15 nm) and nanoparticles (~ 20 nm). Samples 11 and 12 result when carbon nanotubes react with either a stoichiometric mixture of well-dispersed Mo03 powder or with molybdate of impregnated ammonia More evidence of the formation of nanoparticles and nanoparticles of Mo2C is obtained in Sample 12, which results when a stoichiometric mixture of Mo03 and carbon nanotube powder is reacted XRD, SEM and HRTEM analysis showed the formation of both nanorods and Mo2C nanoparticles The SEM analyzes showed a network of nanovarillas with nanoparticles distributed within the network as illustrated in Figure 1. Precise dimensions of carbide nanorods were obtained by HRTEM as illustrated in Figure 2, showing carbide nanorods They have diameters similar to those of carbon nanotubes, that is about 7 nm The particles of carbide nanoparticles or they are in the range of about 7 to about 25 nm in diameter. Sample 12, which was a stoichiometric sample, was studied in more detail in order to learn the course of the reaction. The reaction was followed by thermogravimetric analysis (TGA), as illustrated in Figure 4. Figure 4 shows that the stequometric reaction occurred in two distinct stages, ie reduction of Mo03 by carbon to Mo02 from about 450 to about 550 ° C , followed by further reduction to Mo2C from about 675 ° C to about 725 ° C. Analysis SEM and XRD taken after calcination at 600 ° C showed a complete redistribution of the oxide precursor from the very large μ-supra-Mo03 particles initially present at approximately 20-50 nm particles of Mo03_x, either dispersed between individual fibrils. This redistribution probably occurs through evaporation. Higher calcination at 800 ° C converted Mo03_x, (where x is o or?) Of mixing to nanovarillas and Mo2C nanoparticles, with further reduction in particle size from about 7 to about 25 nm. Although the redistribution of Mo02 is probably carried out through evaporation, both chemical transformations (Mo03? Mo02 and Mo02-> Mo2C by carbon reduction) are considered to occur through solid-solid phase reactions. B. Mo2C nanoparticles supported in carbon nanotubes Analysis of XRD, SEM and HRTEM of products of the Sample 10 provide evidence for successful preparation of Mo2C nanoparticles supported on individual carbon nanotubes. These products were formed by impregnation of ammonium molybdate from aqueous solution on CC aggregates of carbon nanotubes and calcined carefully as illustrated in Table 1. XRD of both products showed the cubic form of Mo2C as the main component together with carbon graffiti Mo2C hexagonal was seen as a minor component. No molybdenum oxide was detected. The cubic Mo2C particles were in the range of about 2 to about 5 nm in diameter, while the hexagonal particles were in the range from about 10 to about 25 nm. The cubic particles were primarily deposited in individual carbon nanotubes, while the hexagonal particles were distributed among carbon nanotubes. These can be seen in Figures 3 and 4, which are copies of HRTEM micrographs taken from Sample 10. In these images, the particle size can be estimated by direct comparison with the diameters of fibrils which is in the range of 7-7. 10 nm. EXAMPLE 8 Preparation Tungsten Carbide Precursors by Impregnation with Ammonium Tungstate The same procedure used in Example 2 above was followed, except that the impregnation solution was an aqueous solution containing the correct amount of paratungstate ammonium hydrate or (NH4) 10W12O41.5H20, 72.% W (here referred to as tungstate of . { ^ k ammonium) required for the charge of C-atom ratio: W (Molar proportions C: W of 3.5: 1, 10: 1 and 20: 1.). The The resulting mixture was dried at 225 ° C under complete vacuum for 18 hours during which the paratungstate compound was decomposed in W03. The sample was set aside for conversion to carbide catalysts by careful calcination under an inert atmosphere as more particularly described fj? 10 in the present Example 10. EXAMPLE 9 Preparation of Tungsten Carbide Precursors by Impregnation with Phosphotungstic Acid (PTA) The same procedure used in the Example 8 above, except that the impregnation solution was an aqueous solution containing the correct amount of phosphotungstic acid, H3 P04.12 W03.xH20, 76.6% W, here referred to as PTA, necessary for the desired atomic ratio loading C: W (proportions molar C: 3.5: 1, 10: 1 and 20: 1.). The resulting mixture was dried at 225 ° C in complete vacuum for 18 hours during which PTA was decomposed to W03. The sample is separated for conversion to carbide catalysts by careful calcination under an inert atmosphere as described above particularly in the present Example 10.

EXAMPLE 10 Calcination of Tungsten Carbide Precursors at 1000 ° C The same procedure as described in Example 7, above was followed to convert precursors of tungsten carbides to tungsten carbides. After cooling in argon, the samples were passivated under 3% 02tAr. Table 3 below summarizes the experimental conditions and results of XRD for selected experiments. TABLE 3. SUMMARY OF RESULTS FOR TUNGSTEN CARBIDE PREPARATIONS 03 (s) + 4C - WC + 3 CO 2W03 (s) + 7C? W22C + 6 CO SAMPLE COMPONENTS T ° C INITIAL PHASES, C; W XRD 1 PTA and Cca 1000 3. 5: 1 WC and W2C 2 PTA and CC 1000 10: 1 WC and W2C 3 PTA and CC 1000 20: 1 WC and W2C 4 A. Tung and Ccb 1000 3. 5: 1 WC and W2C and possibly W A. Tung and CC 1000 10: 1 WC and W2C 6 A. Tung and CC 1000 20: 1 WC and W2C a Dust impregnated with CC aggregates of carbon nanotubes by incipient humidity with phosphotungstic acid b Dust impregnated with aggregates CC of Carbon nanotubes by incipient humidity with paratungstate ammonium hydrate The chemical reactions that occur in these experiments are summarized in Table 3 above. In the component column, there is a list of molybdenum precursors that were converted to W2C / WC by reacting with carbon nanotubes. TPA is referred to as phosphotungstic acid and A. Tung refers to paratungstate ammonium hydrate, "(s)" refers to solid phases of tungsten precursor. C: W refers to the ratio or proportion of atoms C to W in the original mixture. The proportion of stoichiometric atoms to produce pure WC without excess of C or W is 4.0. To produce W2C, the atomic ratio C: W is 3.5. The XRD column lists the compounds observed in the X-ray diffraction analysis (XRD). EXAMPLES 11-13 Preparation of an Extruded Catalyst Support for Carbide and Silicon Nanorodrives SiC nanorods were prepared from Hyperion aggregates of carbon nanotubes according to Example 1 of US Patent Application. Serial No. 08 / 414,369 filed on March 31, 1995 (File of Agent No. KM 6473390), when carbon nanotubes react with SiO vapor at high temperature.

The resulting SiC nanorods have a uniform diameter of 15 nm on average and a highly crystallized ßSiC structure. Poly (dimethylsiloxane) as provided by Aldrich Chemicals, Milwaukee, Wl. , it is used as a binder for the preparation of silicon nanopolymer extrudates. 0.16 g of SiC nanorods and 0.16 g of Poly (dimethylsiloxane) were mixed to form a uniform thick paste. Subsequently, the pulp is pushed through a syringe to produce extruded a green color, which was heated under a circulating argon atmosphere as follows: at 200 ° C for two hours (EXAMPLE 11); at 400 ° C for 4 hours (EXAMPLE 12); and at 700 ° C for 4 hours (EXAMPLE 13). A rigid porous structure of SiC nanorods was formed. The extrudates obtained in Examples 11 to 13 had a density of 0.97 g / cc and a bimodal pore structure. The macropores were 1-5 μm, as illustrated in Figure 5B between aggregates and the mesopores were 10-50 nm, as illustrated in Figure 5C in the interspersed SiC nanovarilla networks. The diameter of the extrudates was approximately 1.2 mm, as illustrated in Figure 5A. The specific surface area of the SiC nanovarilla extrudates was 97 m2 / g. Due to the high surface area, unique pore structure and high temperature stability, SiC extrudates are attractive for various applications, including support for catalysts such as platinum, palladium and the like and carbides of Mo, W, V, Nb or Ta . The surface properties of SiC nanorods when used as a catalyst support are very close to those of carbon. Therefore, conventional carbon supports can be replaced with SiC extrudates and thus extend many properties of carbon supported catalysts to high temperature regions as required in particular for oxidative conditions. EXAMPLES 14 and 15 Preparation of reductive carburization of nanotube-carbon extrudates including molybdenum carbides Two 5-gram samples of carbon nanotube extrudates containing a volatile molybdenum compound prepared according to Example 14 above, are loaded into boats of alumina. Each canister is placed in a tube furnace and heated under argon circulation for two hours at 250 ° C and 450 ° C, respectively. The gas is changed from argon to a mixture of CH4 / H2 (20% CH4) and the furnace is slowly heated (? ° C / minute) to 650 ° C, where the temperature is maintained for one hour. Molybdenum carbides supported on the surface of extruded carbon nanotubes are obtained. EXAMPLE 16 Preparation of reactive chemical transport of extruded molybdenum carbide nanorods. 1 gram of extruded carbon nanotubes, 8 grams of molybdenum powder and 50 mg of bromine contained in a glass capsule, are placed in a quartz tube that is evacuated to 10 ~ 3 torr and then sealed. After the bromine capsule is broken, the tube is placed in a tube oven and heated at 1,000 ° C for about a week. The extruded carbon nanotubes have been substantially converted into molybdenum carbide nanorods. EXAMPLE 17 Preparation of carburization of molybdenum carbides supported on the surface of extruded carbon nanotubes. A sample of carbon nanotube extrudates is placed in a vertical reactor such that a bed is formed. The extrudates are heated under circulating H2 gas at 150 ° C for 2 hours. Subsequently, the extrudates are cooled to 50 ° C. H2 gas is passed through a saturator containing Mo (CO.) 6 at 50 ° C, circulated over the cooled extruded carbon nanotubes. As a result, Mo (CO) 6 is adsorbed on the surface of carbon nanotube extrudates. Following the adsorption stage of Mo (CO) 6, the temperature of the sample rises to 150 ° C in an atmosphere of pure H2. The temperature is maintained at 150 ° C for 1 hour. The temperature of the sample is then increased to 650 ° C and kept at this temperature for 2 hours under circulating H2 gas. A sample of extruded carbon nanotubes containing molybdenum on their surfaces is obtained. This sample is then maintained at 650 ° C for 1 hour and the gas is switched from H2 to a CH4 / H2 mixture (20% CH4). The molybdenum adsorbed on the surfaces of carbon nanotubes is converted into molybdenum carbides. By varying the duration of Mo (CO) 6 adsorption on the extruded cooled carbon nanotubes, the amount of molybdenum carbide formed on the extruded surface can be controlled. The terms and expressions that have been used, are used as terms of description and not limitations, and there is no intention in the use of these terms or expressions to exclude any equivalents of the characteristics shown and described as their portions, recognizing that various modifications within the scope of the invention.

Thus, while what has been described as the preferred embodiments of the present invention has been described, those skilled in the art will appreciate that other and further modifications can be made without departing from the true scope of the invention, and are intended to include all these modifications and changes that fall within the scope of the claims as annexed here.

Claims (3)

1. REXXDICATIONS 1. A composition comprising a multiplicity of oxycarbide-based nanorods having substantially uniform diameters between 1.0 nm and less than 100 nm, the oxycarbide-based nanorods comprise oxycarbides.
2. 2. The composition according to claim 1, characterized in that the oxycarbides have a total amount of oxygen, sufficient to provide at least 25% of at least one mono absorbed oxygen layer as determined by programmed temperature desorption.
3. 3. The composition according to claim 1, characterized in that the oxycarbides are in an amount of about 0.5% to about 25% by weight of the composition 4. The composition according to claim 1, characterized in that substantially uniform diameters are between 3.5 nm and 70 nm 5. The composition according to claim 1, characterized in that the oxycarbon-based nanorods have a substantially solid core of oxycarbons 6. The composition according to claim 1 , characterized in that the oxycarbon-based nanorods are predominantly not fused together 7. - A composition comprising a multiplicity of carbide-based nanorods having substantially uniform diameters between 1.0 nm and 100 nm, wherein the carbide-based nanorods comprise oxycarbides 8. The composition according to claim 7 , characterized in that the oxycarbides have a total amount of oxygen, sufficient to provide at least 25% of at least one monolayer of absorbed oxygen, as determined by programmed temperature desorption. 9. The composition according to claim 7, characterized in that the oxycarbides are on the surface of the carbide-based nanorods. 10. The composition according to claim 7, characterized in that the oxycarbides are in an amount of about 0.5% to about 25% by weight of the composition. 11. The composition according to claim 7, characterized in that the carbide-based nanorods are polycrystalline. 12. The composition according to claim 7, characterized in that the carbide-based nanorods are predominantly fused together. 13. - A composition comprising a multiplicity of carbon nanorods having substantially uniform diameters between 1.0 nm and 100 nm, wherein the carbon nanotubes comprise carbides. 14. The composition according to claim 13, characterized in that the carbides are on the surfaces of the carbon nanotubes. 15. The composition according to claim 13, characterized in that the carbides are in an amount of about 20% to about 100% by weight of carbides. 16. The composition according to claim 13, characterized in that the carbon nanotubes also comprise oxycarbons. 17. The composition according to claim 16, characterized in that the carbides and oxycarbons are on the surfaces of the carbon nanotubes. 18. - The composition according to claim 17, characterized in that the oxycarbides are in an amount of about 0.5% to about 25% by weight of the composition. 19. - The composition according to claim 13 or 16, characterized in that the carbon nanotubes are in the form of aggregated particles. 20. The composition according to claim 19, characterized in that the aggregated particles are in a form selected from the group consisting of bird nests, combed filaments and open network aggregates. 21. The composition according to claim 19, characterized in that the aggregate particles have an average size of less than 700 microns. 22. The composition according to claim 19, characterized in that the carbon nanotubes are substantially cylindrical with a substantially constant diameter, have graffitic layers concentric with the tube axis and are substantially free of pyrolytically deposited carbon. 23. - A composition comprising a multiplicity of carbon nanotubes having substantially uniform diameters between 1.0 nm and 100 nm, wherein the carbon nanotubes comprise a carbide portion, wherein the carbide portion includes carbide-based nanorods. 24. - The composition according to claim 23, characterized in that the carbon nanotubes also comprise an oxycarbide portion. 25. The composition according to claim 24, characterized in that the oxycarbide portion is on the surface of the carbide-based nanovaridges. 26. The composition according to claim 23, characterized in that the carbide portion comprises carbides in an amount from about 20 to about 100% by weight of the composition. 27. The composition according to claim 24, characterized in that the oxycarbide portion comprises oxycarbides in an amount of about 0.5% to about 25% by weight of the composition. 28. The composition according to claim 23 or 24, characterized in that the nanotubes are in the form of aggregated particles. 29. The composition according to claim 23, characterized in that the aggregated particles are in a form selected from the group consisting of bird nests, combed filaments and open net aggregates. 30. - The composition according to claim 29, characterized in that the aggregate particles have an average size of less than 700 microns. 31. The composition according to claim 23, characterized in that the carbon nanotubes are substantially cylindrical with a substantially constant diameter, have concentric graffitic layers with the tube axis and are substantially free of pyrolytically deposited carbon. 32. The composition according to claim 23, characterized in that the carbide portion of the carbon nanotubes has a substantially solid core. 33. - The composition according to claim 23, characterized in that the carbide portion of the nanotubes is polycrystalline. 34. The composition according to claim 23, characterized in that the carbon nanotubes are predominantly fused together. 35.- A rigid porous structure comprising the composition according to claim 1. 36.- The structure according to claim 35, characterized in that the structure has a density greater than 0.5 g / cm3 and a greater porosity of 0.8 cc / g. 37. - The structure according to claim 35, characterized in that it is substantially free of micropores and have a breaking or crushing strength greater than .0703 kg / cm2 (1 lb / in2). 38.- The structure according to claim 35, characterized in that the nanovarillas based on oxycarbide are distributed non-uniformly through the structure. 39.- The structure according to claim 35, characterized in that the oxycarbide-based nanorods are uniformly and evenly distributed throughout the structure. 40. The structure according to claim 39, characterized in that the average distance between the nanovarillas based on oxycarbide is less than about 0.03 miera and greater than about .005 miera. 41.- The structure according to claim 38 or 39, characterized in that the rigid porous structure has at least two dimensions of at least 10 microns and no larger than 2 cm. 42. - The structure according to claim 38 or 39, characterized in that the rigid porous structure has three dimensions of at least 10 microns. 43. - The structure according to claim 38 or 39, characterized in that the rigid porous structure also comprises extruded nanowires based on oxycarbons. 44. The structure according to claim 43, characterized in that the extrudates have a substantially constant diameter, are cylindrical and symmetrical about the longitudinal axis of extrudate. 45. - The structure according to claim 44, characterized in that the diameter of the extrudate is from about 1.0 nm to about 3 cm. 46.- The structure according to claim 43, characterized in that the oxycarbide-based nanorods are connected with a glue agent to form the rigid porous structure. 47. The structure according to claim 46, characterized in that the glue agent is selected from the group consisting of cellulose, carbohydrates, polyethylene, polystyrene, nylon, polyurethane, polyester, polyamides, poly (dimethylsiloxane) and phenolic resins. 48. The structure according to claim 47, characterized in that the rigid porous structure is pyrolyzed. 49. - The structure according to claim 35, characterized in that it has a surface area greater than 10 m2 / gm and preferably greater than 50 m2 / gm. 50.- The rigid porous structure comprising a composition that includes a multiplicity in nanorods based on carbide. 51.- The structure according to claim 50, characterized in that the rigid porous structure has a density greater than 5.0 g / cm3 and a porosity greater than 0.8 cc / g. 52. - The structure according to claim 50, characterized in that the rigid porous structure has two dimensions of at least 10 microns and not greater than 2 cm. 53. The structure according to claim 50, characterized in that it is substantially free of micropores and have a breaking or crushing strength greater than .0703 kg / cm2 (1 lb / in2). 54.- The structure according to claim 50, characterized because, the pore distribution is bimodal. 55. - The structure according to claim 50, characterized in that the carbide-based nanorods 10 $ are distributed non-uniformly through the structure. 56.- The structure according to claim 50, characterized in that the carbide nanorods are distributed evenly and evenly through the structure. 57. The structure according to claim 56, characterized in that the average distance between the carbide nanovarillas is less than about .03 miera and greater than about 0.005 miera. 58. "The structure according to claim 56, characterized in that the rigid porous structure comprises interconnected aggregate particles of carbide-based nanorods 59. The structure according to claim 58, characterized in that the largest average distance between the individual aggregates is less than 0.03 [mu] 60. The structure according to claim 59, characterized in that the rigid porous structure comprises aggregate spacings between the interconnected aggregate particles and the spacings of carbide-based nanorods between the nanorods within the particles of aggregate. 61. - The structure according to claim 58, characterized in that the aggregate particles are in the form of bird nests, combed filaments and open network aggregates. 62. - The structure according to claim 58, characterized in that the rigid porous structure further comprises extruded aggregate particles of nanorods based on carbide. 63. - The structure according to claim 62, characterized in that the extrudates have a substantially constant diameter, are cylindrical and symmetrical about the longitudinal axis of extrudate. 64.- The structure according to claim 63, characterized in that the diameter of the extrudate is approximately 1.0 mm to approximately 3 cm. 65.- The structure according to claim 64, characterized in that the aggregate particles are connected with a glue agent to form the rigid porous structure. 66.- The structure according to claim 65, characterized in that the glue agents are selected from the group consisting of cellulose, carbohydrates, polyethylene, polystyrene, nylon, polyurethane, polyester, polyamides, poly (dimethylsiloxane) and phenolic resins. 67. - The structure according to claim 65, characterized in that the rigid porous structure is pyrolyzed. 68.- The structure according to claim 50, characterized in that it has a surface area greater than 10 m2 / gm and preferably greater than 50 m2 / gm. 69. - A rigid porous structure comprising the composition of claim 7. The rigid porous structure according to claim 69, characterized in that the siccarbides are on the surface of the carbide-based nanorods. 71. - The rigid porous structure according to claim 69, characterized in that the oxycarbides are in an amount of about 0.5% to about 25% by weight of the rigid porous structure. 72. - The structure according to claim 69, characterized in that the structure has at least two dimensions of at least 10 microns and not more than 2 cm. 73. - The structure according to claim 69, characterized in that the structure has at least three dimensions of at least 10 microns. 74. - The rigid porous structure according to claim 69, characterized in that the structure has a greater density 0.5 g / cm3 and a greater porosity than 0. 8 cc / g. The structure according to claim 69, characterized in that it is substantially free of micropores and has a crushing or breaking strength greater than .0703 kg / cm2 (1 lb / in2). 76.- The structure according to claim 69, characterized in that the carbide-based nanorods are distributed non-uniformly through the structure. 77.- The structure according to claim 69, characterized in that the carbide-based nanorods are distributed uniformly and evenly throughout the structure. 78. - The structure according to claim 69, characterized in that the average distance between the carbide-based nanorods is less than about 0.03 miera and more than about 0.005 miera. 79. - The structure according to claim 69, characterized in that the structure comprises interconnected aggregate particles of carbide-based nanorods. 80.- The structure according to claim 79, characterized in that the largest average distance between the individual aggregates is less than 0.03 μ. 81. The structure according to claim 80, characterized in that it comprises aggregate spacings between interconnected aggregate particles and nanowire spacings between the carbide-based nanorods within the aggregate particles. 82. The structure according to claim 79, characterized in that the aggregate particles are in the form of bird nests, combed filaments or open net aggregates. 83.- The structure according to claim 79, characterized in that the structure comprises extrusions of interconnected aggregate particles of carbide-based nanorods. 84. - The structure according to claim 83, characterized in that the extrudates have a substantially constant diameter, are cylindrical and symmetrical about the extruded elongated shaft. 85. - The structure according to claim 84, characterized in that the diameter of the extrudate is from about 1.0 mm to about 3 cm. 86.- The structure according to claim 79, characterized in that the aggregate particles are connected with a glue agent to form the rigid porous structure. 87. The structure according to claim 86, characterized in that the glue agents are selected from the group consisting of cellulose, carbohydrates, polyethylene, polystyrene, nylon, polyurethane and polyester, polyamides, poly (dimethylsiloxane) and phenolic resins. 88.- The structure according to claim 87, characterized in that the rigid porous structure is pyrolyzed. 89.- The structure according to claim 69, characterized in that it has a surface area greater than 10 m2 / gm and not less than 50 m2 / gm. 90.- A rigid porous structure comprising the composition of claim 13. 31.- The rigid porous structure according to claim 96, characterized in that the carbides are on the surface of carbon nanotubes. 92. - The rigid porous structure according to claim 90, characterized in that the carbides are present in an amount from about 20 to about 100% by weight of the structure. 93. - The rigid porous structure according to claim 90, characterized in that the carbon nanotubes also comprise oxycarbons. 94. The rigid porous structure according to claim 90, characterized in that the oxycarbides are on the surface of the carbon nanotubes. 95. The rigid porous structure according to claim 90 to 93, characterized in that the structure has a density greater than 5.0 g / cm3 and a porosity greater than 0.8 cc / g. 96.- The rigid porous structure according to claim 96, characterized in that the structure is substantially free of micropores and has a crushing or breaking strength greater than .0703 kg / cm2 (1 lb / in2). 97. The rigid porous structure according to claim 95, characterized in that the carbon nanotubes are distributed non-uniformly through the structure. 98. - The rigid porous structure according to claim 95, characterized in that the carbon nanotubes are distributed uniformly and evenly through the structure. 99. - The rigid porous structure according to claim 95, characterized in that the average distance between the carbon nanotubes is less than about 0.03 miera and greater than about 0.005 miera. 100.- The rigid porous structure according to claim 95, characterized in that the carbon nanotubes are in the form of aggregate particles interconnected to form the structure. 101. The rigid porous structure according to claim 100, characterized in that the largest average distance between the individual aggregates is less than 0.03, μ. 102.- The rigid porous structure according to claim 100, characterized in that the structure comprises aggregate spacings between particles of interconnected aggregates and spacings of carbon nanotubes between the nanotubes within the aggregated particles. 103. - The rigid porous structure according to claim 100, characterized in that the aggregated particles are in the form of bird nests, combed filaments or open network aggregates. 104.- The structure according to claim 100, characterized in that the rigid porous structure comprises extruded interconnected aggregate particles of the carbon nanotubes. 105. The structure according to claim 104, characterized in that the extrudates have a substantially constant diameter, are cylindrical and symmetrical about the longitudinal axis of the extrudate. 106. The structure according to claim 105, characterized in that the diameter of the extrudate is from about 1.0 mm to about 3 cm. 107.- The structure according to claim 100, characterized in that the aggregate particles are connected with a glue agent to form the rigid porous structure 108.- The structure according to claim 107, characterized in that the glue agents are they choose from the group consisting of cellulose, carbohydrates, polyethylene, polystyrene, nylon, polyurethane, polyester, polyamides, poly (dimethyl siloxane) and phenolic resins. 109. - The structure according to claim 108, characterized in that the rigid porous structure is pyrolyzed. 110.- The structure according to claim 93, characterized in that it has a surface area greater than 10 m2 / gm and preferably greater than 50 m2 / gm 111.- A rigid porous structure comprising the composition of claim 23 or 24 112. A rigid porous structure according to claim 111, characterized in that the structure has a density greater than 0.5 g / cm3 and a porosity greater than 0.8 cc / g. 113. - A rigid porous structure according to claim 111, characterized in that the structure is substantially free of micropores and has a breaking or crushing strength greater than .0703 kg / cm2 (1 lb / in2). 114. - A rigid porous structure according to claim 111, characterized in that the carbon nanotubes are distributed evenly and evenly through the structure. 115. - A rigid porous structure according to claim 111, characterized in that the average distance between the carbon nanotubes is less than about 0.03 miera and greater than about 0.005 miera. 116. The rigid porous structure according to claim 111, characterized in that the carbon nanotubes are in the form of aggregate particles interconnected to form the structure. 117. The rigid porous structure according to claim 116, characterized in that the largest average distance between the individual aggregates is less than 0.03 μ. 118. The rigid porous structure according to claim 111, characterized in that the structure comprises aggregate spacings between interconnected aggregated particles and spacings of carbon nanotubes between the nanorods within the aggregate particles. 119. The rigid porous structure according to claim 116, characterized in that the aggregate particles are in the form of bird nests, combed filaments or open network aggregates. 120. The structure according to claim 111, characterized in that the structure has at least two dimensions, of at least 10 microns and not more than 2 cm. The structure according to claim 111, characterized in that the structure has at least three dimensions of at least 10 microns. 122. The structure according to claim 111, characterized in that the structure further comprises extruded aggregate particles interconnected from the carbon nanotubes. 123. The structure according to claim 122, characterized in that the extrudates have a substantially constant diameter, are cylindrical and symmetrical about the longitudinal axis of the extrudate. 124. The structure according to claim 123, characterized in that the diameter of the extrudate is from about 1.0 mm to about 3 cm. 125. The structure according to claim 116, characterized in that the aggregate particles are connected with a glue agent to form the rigid porous structure. 126. The structure according to claim 125, characterized in that the glue agents are selected from the group consisting of cellulose, carbohydrates, polyethylene, polystyrene, nylon, polyurethane, polyester, polyamides, poly (dimethyl siloxane) and phenolic resins. 127. The structure according to claim 125, characterized in that the rigid porous structure is pyrolyzed. 128. A catalyst comprising the composition of claim 1. 129. The catalyst according to claim 128, for catalyzing a reaction selected from the group consisting of hydrogenation, hydrodesulfurization, hydrodesmetalization, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. 130.. A catalyst characterized in that it comprises the rigid porous structure of claim 35. 131. A supported catalyst for conducting a fluid phase catalytic chemical reaction, characterized in that it comprises: (a) a catalyst support comprising the rigid porous structure of any of the claims 50 to 68; and (b) a catalytically effective amount of catalyst supported in the catalyst support. 132. The supported catalyst according to claim 131, characterized in that it is selected from the group consisting of platinum, palladium, ruthenium, osmium, rhodium, iridium and mixtures thereof. 133. The catalyst supported according to claim 131, characterized in that the catalyst is selected from the group consisting of molybdenum carbide, tungsten carbide, vanadium carbide and mixtures thereof. 134. A method for producing a composition that includes oxycarbide-based nanorods with diameters between 1.0 nm and 100 nm, comprising subjecting carbide-based nanorods to treatment with an oxidizing agent under conditions sufficient to cause the formation of oxycarbons. 135. The method according to claim 134, characterized in that the oxidizing agent is a gas selected from the group consisting of air, oxygen, carbon dioxide, nitric oxide, nitrous oxide, nitrogen dioxide, water vapor and mixtures thereof. 136. The method according to claim 135, characterized in that the gas is mixed with an inert diluent selected from inert gases or nitrogen. 137. The method according to claim 134, characterized in that the oxycarbides are in an amount of about 0.5% to about 25%. 138. The method according to claim 134, characterized in that the conditions are sufficient to convert the carbide-based nanorods into oxycarbide-based nanorods in an amount from about 0.5% to about 25% by weight. 139 ^ The method according to claim 134, characterized in that the conditions are sufficient to cause the formation of oxycarbides predominantly on the surface of the carbide bando nanorods. 140. The method according to claim 134, characterized in that the carbide-based nanorods are prepared by a method comprising contacting carbon nanotubes with a compound based on Q, under sufficient conditions to form carbide nanorods. 141. The method according to claim 140, characterized in that the carbon nanotubes are in the form of aggregates. 142. The method according to claim 140, characterized in that the conditions are sufficient to convert the carbon nanotubes into carbide nanoprids in an amount of about 20% to 100% by weight. 143. A method for producing a rigid porous structure, including carbide-based nanorods, characterized in that it comprises: (i) providing a rigid porous structure of carbon nanotubes; and (ii) contacting the rigid porous structure of the carbon nanotubes with a compound based on Q, under conditions sufficient to form carbide nanorods. 144. The method according to claim 143, characterized in that the carbide-based nanorods are in an amount of about 40% to about 100% by weight. 145. The method according to claim 143, characterized in that the carbide-based nanorods are predominantly on the surface of the carbon nanotubes. 146. A method for producing a rigid porous structure including carbide-based nanorods, characterized in that it comprises: (i) forming a suspension of carbide nanorods in a medium containing glue agents; (ii) separating the medium from the carbide nanorodium suspension; and (iii) pyrolyzing the suspension to form the rigid porous structure including carbide nanovarillas. 147. A method for producing a rigid porous structure including oxycarbide nanowires, characterized in that it comprises treating the rigid porous structure including carbide nanorods of claim 143 or 146, with an oxidizing agent selected from the group consisting of air, oxygen, carbon dioxide , nitric oxide, nitrous oxide, nitrogen dioxide, water vapor and their mixtures. 148. A method for producing carbon nanotubes including carbides, characterized in that it comprises contacting carbon nanotubes with a Q-based compound, under conditions sufficient to form carbides on the surface of the carbon nanotubes. 149. The method according to claim 148, characterized in that the conditions include a temperature from about 400 ° C to about 1000 ° C. 150. The method according to claim 148, characterized in that it further comprises subjecting the carbon nanotubes including carbides, to treatment with an oxidizing agent, in this way forming carbon nanotubes including carbides and oxycarbides. 151. The method according to claim 150, characterized in that the oxidizing agent is selected from the group consisting of air, oxygen, carbon dioxide, nitric oxide, nitrous oxide, nitrogen dioxide, water and mixtures thereof. 152. The method according to claim 150, characterized in that the carbides and oxycarbons are on the surface of the carbon nanotubes. 153. A method for producing a rigid porous structure having carbon nanotubes including carbides, characterized in that it comprises: (i) forming a suspension from carbon nanotubes of claim 148 in a medium; (ii) separating the medium from the suspension; and (iii) pyrolyzing the suspension to form the rigid porous structure comprising carbon nanotubes including carbides. 154. A method for producing a rigid porous structure having carbon nanotubes including carbides and oxycarbons, characterized in that it comprises: (i) forming a suspension of the carbon nanotubes of claim 150 in a medium; (ii) separating the medium from the suspension; and (iii) pyrolyzing the suspension to form the rigid porous structure comprising carbon nanotubes including carbides and oxycarbons. 155. A method for producing a composition that includes carbide-based nanorods having oxycarbons, characterized in that it comprises contacting carbide-based nanorods with an oxidizing agent under conditions sufficient to form oxycarbides in an amount of about 0.5% to about 25% by weight. 156. A method for producing a rigid porous structure including carbide nanowire extrudates, characterized in that it comprises: (i) providing a rigid porous structure including carbon nanotube extrudates; (ii) contacting the rigid porous structure of carbon nanotube extrudates, with a Q-based compound, under conditions sufficient to convert the carbon nanotubes into carbide nanovarillas. 157. A rigid porous structure that includes oxycarbide-based nanorods, characterized in that it comprises: (i) forming a suspension of nanorolabs based on oxycarbide, in a medium containing glue agents; (ii) separating the medium from the suspension; (iii) pyrolysing the suspension to form a rigid porous structure including nanofillers based on oxycarbide. 158. A method for producing a rigid porous structure comprising extrudates including carbide nanovarillas, characterized in that it comprises: (i) forming a paste from carbide-based nanorods; (ii) forming extrudates from the pulp; and (iii) pyrolyzing the extrudates to form a rigid porous structure including carbide-based nanorods. 159. A method for producing a rigid porous structure comprising extrudates including carbide nanowires having oxycarbides, characterized in that it comprises treating the extrudates including carbide nanorods of claim 156 or 158 with an oxidizing agent selected from the group consisting of air, oxygen, carbon dioxide, nitric oxide, nitrous oxide, nitrogen dioxide, water and their mixtures. 160. A process for producing a supported catalyst for conducting a fluid phase catalytic reaction, characterized by comprising incorporating a catalytically effective amount of a catalyst in a support, comprising carbide-based nanorods. 161. The method according to claim 160, characterized in that the carbide-based nanorods in the support are nanorods based on Q, wherein Q is selected from the group consisting of B, Si and Al. 162. The process according to claim 160 or 161, characterized in that the catalyst comprises carbide-based nanorods which are nanorods based on Q, Q is selected from the group consisting of Ti, Ta, Nb, Zr, Hf, Mo, V, and W. 163. The Process according to claim 160, characterized in that the catalytic reaction in catalyzed fluid phase is a reaction selected from the group consisting of hydrogenation, hydrodesulfurization, hydrodesnitrogenation, hydrodesmetalization, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation. 164. A process for producing a supported catalyst for conducting a fluid phase catalytic reaction, characterized in that it comprises incorporating a catalytically effective amount of a catalyst in a support, the catalyst comprising at least one nanovariella based on Q, wherein Q is chosen from the group consisting of Ti, Ta, Nb, Zr, Hf, Mo, V and W., 165. A process for producing a supported catalyst for conducting a fluid phase catalytic reaction, characterized in that it comprises incorporating a catalytically effective amount of a catalyst. in a support, the catalyst comprises the composition of claim 1. 166. The process according to claim 165, characterized in that the catalyzed fluid phase catalytic reaction is a reaction selected from the group consisting of hydrogenation, hydrodesulfurization, hydrodesnitrogenation, hydrodesmetalization, hydrodeoxygenation, hydrodesaromatization, dehydrogenation, hydrogenolysis, isomerization, alkylation, dealkylation and transalkylation .