EP2611766A1

EP2611766A1 - Process for producing carbon-comprising composite

Info

Publication number: EP2611766A1
Application number: EP11821197.8A
Authority: EP
Inventors: Natalia Trukhan; Ulrich Müller; Emi Leung; Alexander Panchenko; Nicole Janssen
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2010-09-01
Filing date: 2011-08-18
Publication date: 2013-07-10
Also published as: TW201223962A; CA2809928A1; BR112013004984A2; RU2013114186A; KR20130101038A; WO2012028989A1; CN103180282A; EP2611766A4; AU2011298030A1; JP2013537877A; MX2013002219A

Abstract

A process for producing a carbon-comprising composite is provided, wherein a porous metal-organic framework comprising at least one at least bidentate organic compound coordinated to at least one metal ion is pyrolyzed under a protective gas atmosphere and the at least one at least bidentate organic compound is nitrogen-free. Composites which can be obtained in this way and sulfur electrodes comprising these and also their uses are further provided.

Description

PROCESS FOR PRODUCING CARBON-COMPRISP G COMPOSITE

Description The present invention relates to a process for producing a carbon-comprising composite. The invention further relates to composites which can be obtained in this way and sulfur electrodes comprising these and also their uses.

Composites are materials which comprise two or more bonded materials. Their precise chemical composition is frequently unknown, so that they usually have to be characterized by the process for producing them and also the starting materials.

These materials can have properties which cannot be expected to the same extent, if at all, from their starting materials.

An example is a composite produced from a porous metal-organic framework made up of cobalt ions and a nitrogen-comprising ligand (1 ,3,5-triazine-2,4,6-triyltrisglycine, TTG). This composite is produced by pyrolysis and, owing to its nitrogen content, has good separation properties for the separation of C0₂/CH₄ (Y. Shen et al., Chem. Commun. 46 (2010), 1308-1310).

Despite the composites known in the prior art, there is a need for further materials.

It is therefore an object of the present invention to provide such materials and processes for producing them.

The object is achieved by a process for producing a carbon-comprising composite, which comprises the step (a) Pyrolysis of a porous metal-organic framework comprising at least one at least bidentate organic compound coordinated to at least one metal ion under a protective gas atmosphere, where the at least one at least bidentate organic compound is nitrogen-free.

The process of the invention can comprise a further step (b). Here, an at least partial removal of one or more metal components from the composite obtained in step (a) is carried out.

This metal component or these metal components result from the transformation of the at least one metal ion comprised in the porous metal-organic framework. Furthermore, the process of the invention can comprise a step (c) in which the composite obtained from step (a) or (b) is impregnated with sulfur.

The pyrolysis can be carried out by processes known in the prior art.

The pyrolysis in step (a) is preferably carried out at a temperature of at least 500°C, preferably at least 600°C. The pyrolysis is more preferably carried out in a temperature range from 600°C to 1000°C, even more preferably in the range from 600°C to 800°C. Process step (a) is carried out under a protective gas atmosphere. The protective gas atmosphere is preferably an atmosphere of nitrogen. Other generally known protective gases such as noble gases are also possible.

A porous metal-organic framework is used as starting material. This comprises at least one at least bidentate organic compound coordinated to at least one metal ion, where the at least one at least bidentate organic compound is nitrogen-free.

Such metal-organic frameworks (MOFs) are known in the prior art and are described, for example, in US 5,648,508, EP-A-0 790 253, M. O'Keeffe et al., J. Sol. State Chem., 152 (2000), pages 3 to 20, H. Li et al., Nature 402, (1999), page 276, M. Eddaoudi et al., Topics in Catalysis 9, (1999), pages 105 to 1 1 1 , B. Chen et al., Science 291 , (2001 ), pages 1021 to 1023, DE-A-101 1 1 230, DE-A 10 2005 053430, WO-A 2007/054581 , WO-A 2005/049892 and WO-A 2007/023134. As a specific group of these metal-organic frameworks, the recent literature has described "limited" frameworks in which the network does not extend infinitely but rather with formation of polyhedra as a result of specific selection of the organic compound. A.C. Sudik, et al., J. Am. Chem. Soc. 127 (2005), 71 10-71 18, describe such specific frameworks. Here, these will be referred to as metal-organic polyhedra (MOP) to distinguish them.

The metal-organic frameworks according to the present invention comprise pores, in particular micropores and/or mesopores. Micropores are defined as pores having a diameter of 2 nm or less and mesopores are defined by a diameter in the range from 2 to 50 nm, in each case, corresponding to the definition given in Pure & Applied Chem. 57 (1983), 603 - 619, in particular on page 606. The presence of micropores and/or misopores can be checked by means of sorption measurements which determine the uptake capacity for nitrogen of the MOF at 77 kelvin in accordance with DIN 66131 and/or DIN 66134. The specific surface area, calculated according to the Langmuir model (DIN 66131 , 66134) for an MOF in powder form is greater than 100 m²/g, more preferably above 300 m²/g, more preferably greater than 700 m²/g, even more preferably greater than 800 m²/g, even more preferably greater than 1000 m²/g and particularly preferably greater than 1200 m²/g.

Shaped bodies comprising metal-organic frameworks can have a relatively low active surface area, but this is preferably greater than 150 m²/g, more preferably greater than 300 m²/g, even more preferably greater than 700 m²/g.

The metal component in the framework according to the present invention is preferably selected from groups la, lla, Ilia, IVa to Villa and lb to Vlb. Particular preference is given to Mg, Ca, Sr, Ba, Sc, Y, Ln, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ro, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, TI, Si, Ge, Sn, Pb, As, Sb and Bi, where Ln denotes lanthanides.

Lanthanides are La, Ce, Pr, Nd, Pm, Sm, En, Gd, Tb, Dy, Ho, Er, Tm, Yb.

With regard to the ions of these elements, particular mention may be made of Mg²⁺, Ca²⁺, Sr , Ba²⁺, Sc³⁺, Y³⁺, Ln³⁺, Ti⁴⁺, Zr⁴⁺, Hf⁴⁺, V⁴⁺, V³⁺, V²⁺, Nb³⁺, Ta³⁺, Cr³⁺, Mo³⁺, W³⁺, Mn³⁺, Mn²⁺, Re³⁺, Re²⁺, Fe³⁺, Fe²⁺, Ru³⁺, Ru²⁺, Os³⁺, Os²⁺, Co³⁺, Co²⁺, Rh²⁺, Rh⁺, Ir²", lr⁺, Ni²⁺, Ni⁺, Pd²⁺, Pd⁺, Pt²⁺, Pt⁺, Cu²⁺, Cu⁺, Ag⁺, Au⁺, Zn²⁺, Cd²⁺, Hg²⁺, Al³⁺, Ga³⁺, ln³⁺, Tl³⁺, Si⁴⁺, Si²⁺, Ge⁴⁺, Ge²⁺, Sn⁴⁺, Sn²⁺, Pb⁴⁺, Pb²⁺, As⁵⁺, As³⁺, As⁺, Sb⁵⁺, Sb³⁺, Sb⁺, Bi⁵⁺, Bi³⁺ and Bi⁺.

Mg, Al, Zr, Ti, V, Cr, Mo, Fe, Co, Cu, Ni, Zn are more particularly preferred. Greater preference is given to Al, Ti, Mg, Fe, Cu and Zn. Very particular preference is given to Mg, Al, Cu and Zn. The term "at least bidentate organic compound" refers to an organic compound which comprises at least one functional group which is able to form at least two coordinate bonds to a given metal ion and/or to form one coordinate bond to each of two or more, preferably two, metal atoms. As functional groups via which the abovementioned coordinate bonds can be formed, mention may be made by way of example of, in particular, the following functional groups: -C0₂H, -CS₂H, -N0₂, -B(OH)₂, -S0₃H, -Si(OH)₃, -Ge(OH)₃, -Sn(OH)₃, -Si(SH)₄, -Ge(SH)₄, -Sn(SH)₃, -P0₃H, -As0₃H , -As0₄H, -P(SH)₃, -As(SH)₃, -CH(RSH)₂, -C(RSH)₃ -CH(ROH)₂, -C(ROH)₃, where R is, for example, preferably an alkylene group having 1 , 2, 3, 4 or 5 carbon atoms, for example a methylene, ethylene, n-propylene, i- propylene, n-butylene, i-butylene, tert-butylene or n-pentylene group, or an aryl group comprising 1 or 2 aromatic rings, for example 2 C₆ rings, which may optionally be fused and may be appropriately substituted independently of one another by in each case at least one substituent and/or may comprise, independently of one another, in each case at least one heteroatom such as O and/or S. In likewise preferred embodiments, mention may be made of functional groups in which the abovementioned radical R is not present. Such groups are, inter alia, CH(SH)₂, -C(SH)₃, -CH(OH)₂, or -C(OH)₃.

The at least two functional groups can in principle be bound to any suitable organic compound as long as it is ensured that the organic compound bearing these functional groups is capable of forming the coordinate bond and of producing the framework.

The organic compounds comprising the at least two functional groups are preferably derived from a saturated or unsaturated aliphatic compound or an aromatic compound or a both aliphatic and aromatic compound.

The aliphatic compound or the aliphatic part of the both aliphatic and aromatic compound can be linear and/or branched and/or cyclic, with a plurality of rings per compound also being possible. The aliphatic compound or the aliphatic part of the both aliphatic and aromatic compound more preferably comprises from 1 to 15, more preferably from 1 to 14, more preferably from 1 to 13, more preferably from 1 to 12, more preferably from 1 to 1 1 and particularly preferably from 1 to 10, carbon atoms, for example 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. Particular preference is given here to, inter alia, methane, adamantine, acetylene, ethylene or butadiene. The aromatic compound or the aromatic part of the both aromatic and aliphatic compound can have one or more rings, for example two, three, four or five rings, with the rings being able to be present separately and/or with at least two rings being fused. The aromatic compound or the aromatic part of the both aliphatic and aromatic compound particularly preferably has one, two or three rings, with one or two rings being particularly preferred. Each ring of the compound mentioned can also independently comprise at least one heteroatom such as O, S, B, P, Si, Al, preferably N, O and/or S. The aromatic compound or the aromatic part of the both aromatic and aliphatic compound more preferably comprises one or two C₆ rings, with the rings being present either separately or in a fused form. Particular mention may be made of benzene, naphthalene and/or biphenyl as aromatic compounds.

The at least bidentate organic compound is more preferably an aliphatic or aromatic, acyclic or cyclic hydrocarbon which has from 1 to 18, preferably from 1 to 10 and in particular 6, carbon atoms and additionally has exclusively 2, 3 or 4 carboxyl groups as functional groups. For example, the at least bidentate organic compound is derived from a dicarboxylic acid such as oxalic acid, succinic acid, tartaric acid, 1 ,4-butanedicarboxylic acid, 1 ,4- butenedicarboxylic acid, 4-oxopyran-2,6-dicarboxylic acid, 1 ,6-hexanedicarboxylic acid, decanedicarboxylic acid, 1 ,8-heptadecanedicarboxylic acid, 1 ,9-hepta- decanedicarboxylic acid, heptadecanedicarboxylic acid, acetylenedicarboxylic acid, 1 ,2-benzenedicarboxylic acid, 1 ,3-benzenedicarboxylic acid, 1 ,3-butadiene-1 ,4- dicarboxylic acid, 1 ,4-benzenedicarboxylic acid, p-benzenedicarboxylic acid, thiophene-3,4-dicarboxylic acid, tetrahydropyran-4,4-dicarboxylic acid, perylene-3,9- dicarboxylic acid, perylenedicarboxylic acid, pluriol E 200-dicarboxylic acid, 3,6- dioxaoctanedicarboxylic acid, 3,5-cyclohexadiene-1 ,2-dicarboxylic acid, octadicarboxylic acid, pentane-3,3-carboxylic acid, 1 ,1 '-dinaphthyldicarboxylic acid, polytetrahydrofuran-250-dicarboxylic acid, 1 ,4,5,6,7,7-hexachloro-5-norbornene-2,3- dicarboxylic acid, phenylindanedicarboxylic acid, 1 ,4-cyclohexanedicarboxylic acid, naphthalene-1 ,8-dicarboxylic acid, 2-benzoylbenzene-1 ,3-dicarboxylic acid, 3,6,9- tnoxaundecanedicarboxylic acid, hydroxybenzophenonedicarboxylic acid, pluriol E 300- dicarboxylic acid, pluriol E 400-dicarboxylic acid, pluriol E 600-dicarboxylic acid, 1 ,4- naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1 ,3- adamantanedicarboxylic acid, 1 ,8-naphthalenedicarboxylic acid, 2,3- naphthalenedicarboxylic acid, 8-methoxy-2,3-naphthalenedicarboxylic acid, 8-sulfo-2,3- naphthalenedicarboxylic acid, anthracene-2,3-dicarboxylic acid, 2',3'-diphenyl-p- terphenyl-4,4"-dicarboxylic acid, (diphenyl ether)-4,4'-dicarboxylic acid, 4(1 H)- oxothiochromene-2,8-dicarboxylic acid, 5-tert-butyl-1 ,3-benzenedicarboxylic acid, 4- cyclohexene-1 ,2-dicarboxylic acid, hexatriacontanedicarboxylic acid, tetradecanedicarboxylic acid, 1 ,7-heptanedicarboxylic acid, 5-hydroxy-1 ,3- benzenedicarboxylic acid, 2,5-dihydroxy-1 ,4-dicarboxylic acid, furan-2,5-dicarboxylic acid, 1 -nonene-6,9-dicarboxylic acid, eicosenedicarboxylic acid, 4,4'- dihydroxydiphenylmethane-3,3'-dicarboxylic acid, cyclohexene-2,3-dicarboxylic acid, 2,4-dichlorobenzophenone-2',5'-dicarboxylic acid, 1 ,3-benzenedicarboxylic acid, anthraquinone-1 ,5-dicarboxylic acid, 2-nitrobenzene-1 ,4-dicarboxylic acid, heptane-1 ,7- dicarboxylic acid, cyclobutane-1 , 1 -dicarboxylic acid, 1 ,14-tetradecanedicarboxylic acid, 5,6-dehydronorbornane-2,3-dicarboxylic acid or camphordicarboxylic acid.

The at least bidentate organic compound is even more preferably one of the dicarboxylic acids mentioned by way of example above as such.

The at least bidentate organic compound can, for example, be derived from a tricarboxylic acid such as

2-hydroxy-1 ,2,3-propanetricarboxylic acid, 1 ,2,3-, 1 ,2,4-benzenetricarboxylic acid, 1 ,2,4-butanetricarboxylic acid, 2-phosphono-1 ,2,4-butanetricarboxylic acid, 1 ,3,5- benzenetricarboxylic acid, 1 -hydroxy-1 ,2,3-propanetricarboxylic acid, 5-acetyl-3-amino- 6-methylbenzene-1 ,2,4-tricarboxylic acid, 1 ,2,3-propanetricarboxylic acid or aurintricarboxylic acid.

The at least bidentate organic compound is even more preferably one of the tricarboxylic acids mentioned by way of example above as such.

Examples of an at least bidentate organic compound derived from a tetracarboxylic acid are 1 ,1 -dioxidoperylo[1 ,12-BCD]thiophene-3,4,9,10-tetracarboxylic acid, perylene- tetracarboxylic acids such as perylene-3,4,9,10-tetracarboxylic acid or (perylene 1 ,12- sulfone)-3,4,9,10-tetracarboxylic acid, butanetetracarboxylic acids such as 1 ,2,3,4- butanetetracarboxylic acid or meso-1 ,2,3,4-butanetetracarboxylic acid, decane-2, 4,6,8- tetracarboxylic acid , 1 ,4,7,10,13,16-hexaoxacyclooctadecane-2,3, 1 1 , 12-tetracarboxylic acid, 1 ,2,4,5-benzenetetracarboxylic acid, 1 ,2,1 1 ,12-dodecanetetracarboxylic acid, 1 ,2,5,6-hexanetetracarboxylic acid, 1 ,2,7,8-octanetetracarboxylic acid, 1 ,4,5,8- naphthalenetetracarboxylic acid, 1 ,2,9,10-decanetetracarboxylic acid, benzophenonetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, tetrahydrofurantetracarboxylic acid or cyclopentanetetracarboxylic acids such as cyclopentane-1 ,2,3,4-tetracarboxylic acid.

The at least bidentate organic compound is even more preferably one of the tetracarboxylic acids mentioned by way of example above as such. Very particular preference is given to optionally at least monosubstituted aromatic dicarboxylic, tricarboxylic or tetracarboxylic acids having one, two, three, four or more rings with each of the rings being able to comprise at least one heteroatom and two or more rings being able to comprise identical or different heteroatoms. Preference is given, for example, to monocyclic dicarboxylic acids, monocyclic tricarboxylic acids, monocyclic tetracarboxylic acids, dicyclic dicarboxylic acids, dicyclic tricarboxylic acids, dicyclic tetracarboxylic acids, tricyclic dicarboxylic acids, tricyclic tricarboxylic acids, tricyclic tetracarboxylic acids, tetracyclic dicarboxylic acids, tetracyclic tricarboxylic acids and/or tetracyclic tetracarboxylic acids. Suitable heteroatoms are, for example, O, S, B, P, and preferred heteroatoms among these are S and/or O. As suitable substituents, mention may be made of, inter alia, -OH, a nitro group, an alkyl or alkoxy group.

Particular preference is given to using acetylenedicarboxylic acid (ADC), camphordicarboxylic acid, fumaric acid, succinic acid, benzenedicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid (BDC), naphthalenedicarboxylic acids (NDC), biphenyldicarboxylic acids such as 4,4'-biphenyldicarboxylic acid (BPDC), benzenetricarboxylic acids such as 1 ,2,3-, 1 ,2,4-benzenetricarboxylic acid or 1 ,3,5- benzenetricarboxylic acid (BTC), benzenetetracarboxylic acid, adamantanetetracarboxylic acid (ATC), adamantanedibenzoate (ADB), benzenetribenzoate (BTB), methanetetrabenzoate (MTB), adamantanetetrabenzoate or dihydroxyterephthalic acids such as 2,5-dihydroxyterephthalic acid (DHBDC), tetrahydropyrene-2,7-dicarboxylic acid (HPDC), biphenyltetracarboxylic acid (BPTC) as at least bidentate organic compounds.

Very particular preference is given to, inter alia, phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, 1 ,4-naphthalenedicarboxylic acid, 1 ,5-naphthalenedicarboxylic acid, 1 ,2,3-benzenetricarboxylic acid, 1 ,2,4- benzenetricarboxylic acid, 1 ,3,5-benzenetricarboxylic acid, 1 ,2,4,5- benzenetetracarboxylic acid, fumaric acid, biphenyldicarboxylate, 1 ,5- and 2,6- naphthalenedicarboxylic acid, tert-butylisophthalic acid, dihydroxybenzoic acid, BTB, HPDC, BPTC.

Apart from these at least bidentate organic compounds, the metal-organic framework can also comprise one or more monodentate ligands and/or one or more at least bidentate ligands which are not derived from a dicarboxylic, tricarboxylic or tetracarboxylic acid.

Apart from these at least bidentate organic compounds, the metal-organic framework can also comprise one or more monodentate ligands. Suitable solvents for preparing the metal-organic framework are, inter alia, ethanol, dimethylformamide, toluene, methanol, chlorobenzene, diethylformamide, dimethyl sulfoxide, water, hydrogen peroxide, methylamine, sodium hydroxide solution, N- methylpyrrolidone ether, acetonitrile, benzyl chloride, triethylamine, ethylene glycol and mixtures thereof. Further metal ions, at least bidentate organic compounds and solvents for the preparation of MOF are described, inter alia in US-A 5,648,508 or DE-A 101 1 1 230.

The pore size of the metal-organic framework can be controlled by selection of the suitable ligand and/or the at least bidentate organic compound. In general, the larger the organic compound, the greater the pore size. The pore size is preferably from 0.2 nm to 30 nm, particularly preferably in the range from 0.3 nm to 3 nm, based on the crystalline material.

Examples of metal-organic frameworks are given below. In addition to the name of the framework, the metal and the at least bidentate ligand, the solvent and the cell parameters (angles α, β and γ and the spacings A, B and C in A) are indicated. The latter were determined by X-ray diffraction.

86.90 mmol

0.034 mmol ol

8.69 mmol

0.0428 mmol

0.12 mmol

ADC Acetylenedicarboxylic acid

NDC Naphthalenedicarboxylic acid

BDC Benzenedicarboxylic acid

ATC Adamantanetetracarboxylic acid

BTC Benzenetricarboxylic acid

BTB Benzenetribenzoic acid

MTB Methanetetrabenzoic acid

ATB Adamantanetetrabenzoic acid

ADB Adamanetandibenzoic acid

Further metal-organic frameworks are MOF-69 to 80, MOF103 to 106, MOF-177, MOF- 235, MOF-236, MOF-501 , MOF-502, MOF-505, IRMOF-1 , IRMOF-61 , IRMOP-51 , MIL- 45, MIL-47, MIL-53, MIL-59, MIL-60, MIL-61 , MIL-63, MIL-68, MIL-85, which are described in the literature.

Particularly preferred metal-organic frameworks are MIL-53, Zn-tBu-isophthalic acid, AI-BDC, MOF-5, MOF-177, MOF-505, IRMOF-8, IRMOF-1 1 , Cu-BTC, AI-NDC, AI-BTC, Cu-BTC, AI-NDC, Mg-NDC, Al-fumarate, MOF-74, Sc-terephthalate. Even greater preference is given to AI-BDC, Al-fumarate, AI-NDC, AI-BTC and Cu-BTC.

The nitrogen-free at least one at least bidentate organic compound is preferably derived from a dicarboxylic, tricarboxylic or tetracarboxylic acid. For the purposes of the present invention, the term "derived" means that the at least one at least bidentate organic compound is present in partially or fully deprotonated form, as far as the carboxy functions are concerned. Furthermore, the term "derived" means that the at least one at least bidentate organic compound can have further substituents. Thus, one or, independently of one another, more substituents such as hydroxyl, methoxy, halogen or methyl groups can be present in addition to the carboxylic acid function. It is preferred that no further substituent, or only F substituents, is/are present. For the purposes of the present invention, the term "derived" also means that the carboxylic acid function can be present as sulfur analogues. Sulfur analogues are -C(=0)SH and the tautomer thereof and -C(S)SH. Preference is given to no sulfur analogues being present.

Apart from the conventional method of preparing the MOFs, as is described, for example, in US 5,648,508, these can also be prepared by an electrochemical route. In this respect, reference may be made to DE-A 103 55 087 and WO-A 2005/049892. In step (b), an at least partial removal of one or more metal components is carried out. It is preferred that this or these comprise at least one metal oxide.

The at least partial removal is preferably carried out by washing out by means of an alkaline liquid. Other methods known in the prior art can also be used. A suitable alkaline liquid is, for example, an aqueous NaOH solution. Other alkali metal hydroxides are also suitable. Depending on the metal compound, an acid treatment is also possible.

In step (c), an impregnation of the composite obtained from step (a) or (b) is carried out. Impregnation with chemicals is known and can be carried out as in the impregnation of porous metal-organic frameworks. This is described, for example, in the international patent application PCT/EP2010/053530.

The impregnation is preferably effected by mixing and subsequent heating. The impregnation is preferably carried out by mechanical mixing. Sulfur can be introduced as a solid or from a suspension or solution, in particular an organic solution such as a toluene-comprising solution, in particular a toluene solution.

The present invention further provides a composite which can be obtained by a process according to the present invention.

The present invention further provides for the use of a composite material according to the invention which can be obtained by a process according to the invention for absorption of at least one material for the purposes of storage, removal, controlled release, chemical reaction of the material or as support.

The at least one material is preferably a gas or gas mixture.

Storage processes using metal-organic frameworks in general are described in WO-A 2005/003622, WO-A 2003/064030, WO-A 2005/049484, WO-A 2006/089908 and DE-A 10 2005 012 087. The processes described there can also be used for the composite of the invention.

Separation or purification processes using metal-organic frameworks in general are described in EP-A 1 674 555, DE-A 10 2005 000938 and in DE-A 10 2005 022 844. The processes described there can also be used for the composite of the invention.

If the composite of the invention is used for storage, this is preferably carried out in a temperature range from -200°C to +80°C. A temperature range of from -40°C to +80°C is more preferred.

For the purposes of the present invention, the terms "gas" and "liquid" will be used in the interests of simplicity, but gas mixtures and liquid mixtures or liquid solutions are also encompassed by the term "gas" or "liquid".

Preferred gases are hydrogen, natural gas, town gas, hydrocarbons, in particular methane, ethane, ethyne, acetylene, propane, n-butane and also i-butane, carbon monoxide, carbon dioxide, nitrogen oxides, oxygen, sulfur oxides, halogens, halogenated hydrocarbons, NF₃, SF₆, ammonia, boranes, phosphanes, hydrogen sulfide, amines, formaldehyde, noble gases, in particular helium, neon, argon, krypton and xenon.

The gas is particularly preferably carbon dioxide which is separated off from a gas mixture comprising carbon dioxide. The gas mixture preferably comprises carbon dioxide together with at least H₂, CH₄ or carbon monoxide. In particular, the gas mixture comprises carbon monoxide in addition to carbon dioxide. Very particular preference is given to mixtures which comprise at least 10 and not more than 45% by volume of carbon dioxide and at least 30 and not more than 90% by volume of carbon monoxide.

A preferred embodiment is pressure swing adsorption using a plurality of parallel adsorber reactors, with the adsorbent charge consisting entirely or partly of the material according to the invention. The adsorption phase for the C0₂/CO separation preferably takes place at a C0₂ partial pressure of from 0.6 to 3 bar and a temperature of at least 20°C but not more than 70°C. To desorb the adsorbed carbon dioxide, the total pressure in the adsorber reactor concerned is usually reduced to values in the range from 100 mbar to 1 bar.

Preference is also given to the use of the framework of the invention for storing a gas at a minimum pressure of 100 bar (absolute). The minimum pressure is more preferably 200 bar (absolute), in particular 300 bar (absolute). The gas is particularly preferably hydrogen or methane.

However, the at least one material can also be a liquid. Examples of such liquids are disinfectants, inorganic or organic solvents, fuels, in particular gasoline or diesel, hydraulic fluid, radiator fluid, brake fluid or an oil, in particular machine oil. Furthermore, the liquid can be a halogenated aliphatic or aromatic, cyclic or acyclic hydrocarbon or a mixture thereof. In particular, the liquid can be acetone, acetonitrile, aniline, anisole, benzene, benzonitrile, bromobenzene, butanol, tert-butanol, quinoline, chlorobenzene, chloroform, cyclohexane, diethylene glycol, diethyl ether, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, dioxane, glacial acetic acid, acetic anhydride, ethyl acetate, ethanol, ethylene carbonate, ethylene dichloride, ethylene glycol, ethylene glycol dimethyl ether, formamide, hexane, isopropanol, methanol, methoxypropanol, 3-methyl-1 -butanol, methylene chloride, methyl ethyl ketone, N- methylformamide, N-methylpyrrolidone, nitrobenzene, nitromethane, piperidine, propanol, propylene carbonate, pyridine, carbon disulfide, sulfolane, tetrachloroethene, carbon tetrachloride, tetrahydrofuran, toluene, 1 ,1 ,1 -trichloroethane, trichloroethylene, triethylamine, triethylene glycol, triglyme, water or mixtures thereof. Furthermore, the at least one material can be an odorous substance.

The odorous substance is preferably a volatile organic or inorganic compound which comprises at least one of the elements nitrogen, phosphorus, oxygen, sulfur, fluorine, chlorine, bromine or iodine, or is an unsaturated or aromatic hydrocarbon or a saturated or unsaturated aldehyde or a ketone. More preferred elements are nitrogen, oxygen, phosphorus, sulfur, chlorine, bromine; particular preference is given to nitrogen, oxygen, phosphorus and sulfur.

In particular, the odorous substance is ammonia, hydrogen sulfide, sulfur oxides, nitrogen oxides, ozone, cyclic or acyclic amines, thiols, thioethers and also aldehydes, ketones, esters, ethers, acids or alcohols. Particular preference is given to ammonia, hydrogen sulfide, organic acids (preferably acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid, heptanoic acid, lauric acid, pelargonic acid) and also cyclic or acyclic hydrocarbons comprising nitrogen or sulfur and also saturated or unsaturated aldehydes such as hexanal, heptanal, octanal, nonanal, decanal, octenal or nonenal and in particular volatile aldehydes such as butyraldehyde, propionaldehyde, acetaldehyde and formaldehyde and additionally fuels such as gasoline, diesel (constituents). The odorous substances can also be fragrances which are used, for example, for producing perfumes. As fragrances or oils which liberate such fragrances, mention may be made by way of example of: essential oils, basil oil, geranium oil, mint oil, cananga tree oil, cardamom oil, lavender oil, peppermint oil, nutmeg oil, chamomile oil, eucalyptus oil, rosemary oil, lemon oil, lime oil, orange oil, bergamot oil, muscat sage oil, coriander oil, cypress oil, 1 ,1 -dimethoxy-2-phenylethane, 2,4-dimethyl-4- phenyltetrahydrofuran, dimethyltetrahydrobenzaldehyde, 2,6-dimethyl-7-octen-2-ol, 1 ,2-diethoxy-3,7-dimethyl-2,6-octadiene, phenylacetaldehyde, rose oxide, ethyl-2- methylpentanoate, 1 -(2,6,6-trimethyl-1 ,3-cyclohexadien-1 -yl)-2-buten-1 -one, ethylvanillin, 2,6-dimethyl-2-octenol, 3,7-dimethyl-2-octenol, tert-butylcyclohexyl acetate, anisyl acetate, allylcyclohexyloxy acetate, ethyl linalool, eugenol, coumarin, ethyl acetoacetate, 4-phenyl-2,4,6-trimethyl-1 ,3-dioxane, 4-methylene-3, 5,6,6- tetramethyl-2-heptanone, ethyl tetrahydrosafranate, geranyl nitrile, cis-3-hexen-1 -ol, cis-3-hexenyl acetate, cis-3-hexenyl methyl carbonate, 2,6-dimethyl-5-hepten-1 -al, 4- (tricyclo[5.2.1.0]decylidene)-8-butanal, 5-(2,2,3-trimethyl-3-cyclopentenyl)-3- methylpentan-2-ol, p-tert-butyl alpha-methylhydrocinnamaldehyde, ethyl [5.2.1 .0]tricyclodecanecarboxylate, geraniol, citronellol, citral, linalool, linalyl acetate, ionones, phenylethanol or mixtures thereof.

For the purposes of the present invention, a volatile odorous substance preferably has a boiling point or boiling point range of less than 300°C. The odorous substance is more preferably a readily volatile compound or mixture. The odorous substance particularly preferably has a boiling point or boiling range of less than 250°C, more preferably less than 230°C, particularly preferably less than 200°C.

Preference is likewise given to odorous substances which have a high volatility. The vapor pressure can be employed as a measure of the volatility. For the purposes of the present invention, a volatile odorous substance preferably has a vapor pressure of more than 0.001 kPa (20°C). The odorous substance is more preferably a readily volatile compound or mixture. The odorous substance particularly preferably has a vapor pressure of more than 0.01 kPa (20°C), more preferably a vapor pressure of more than 0.05 kPa (20°C). The odorous substances particularly preferably have a vapor pressure of more than 0.1 kPa (20°C).

Examples in which a chemical reaction can take place in the presence of the metal- organic framework of the invention are the alkoxylation of monools and polyols. The method of carrying out such alkoxylations is described in WO-A 03/035717 and WO-A 2005/03069. Likewise, the porous metal-organic framework of the invention can be used for the epoxydation and also preparation of polyalkylene carbonates and hydrogen peroxide. Such reactions are described in WO-A 03/101975, WO-A 2004/037895 and US-A 2004/08161 1.

Particular preference is given to catalytic reactions. In addition, the metal-organic framework of the invention can serve as support, in particular as support for a catalyst. The sulfur-impregnated composites of the present invention, in particular, are suitable as sulfur electrode.

The present invention therefore further provides a sulfur electrode comprising such a composite according to the invention.

The present invention further provides for the use of a sulfur electrode according to the invention in an Li-sulfur battery and also provides an Li-sulfur battery comprising such a sulfur electrode. Examples

Example 1 : Pyrolysis of Al-terephthalic acid MOF

Experimental method:

20 g of AI-MOF (Al-terephthalic acid MOF: 1 100 m²/g determined by the Langmuir method) are introduced into a fused silica tube. This is placed in a tube furnace and flushed overnight with nitrogen. The tube is subsequently heated over a period of 2 hours to 600°C in a stream of nitrogen. During this procedure, the tube is rotated slowly (45 rpm). The powder is pyrolyzed at 600°C for 1 hour. After cooling (about 1 .5 hours), the black powder is removed from the tube.

Weight obtained: 8.7g

Analysis:

Surface area: 387 m²/g determined by the Langmuir method

Elemental analysis: Al 30% by weight

Example 2: NaOH washing of the pyrolyzed Al-terephthalate

Starting materials: 6.47 g of pyrolized material from Example 1

100 g of sodium hydroxide solution, 10% strength

Experimental procedure

a) Synthesis: Pyrolyzed material from Example 1 is stirred with the sodium hydroxide solution at 80°C in a 250 ml four-neck flask for 10 hours.

b) Work-up: The solid is filtered off on a glass frit No. 4 at room temperature, stirred 3 times with 50 ml each time of deionized water, allowed to stand for 5 minutes, filtered off; washed 7 times with 50 ml each time of deionized water. Finally, it is stirred with 25 ml of acetone and sucked dry. c) Drying: 16 hours at 100°C in a vacuum drying oven

Color: black Yield: 2.61 g

Analysis:

Bulk density: 186 g/l

Surface area 1620 m²/g determined by the Langmuir method

Elemental analysis: Al 0.1 % by weight; Na 0.61 % by weight

Example 3: Loading of the material from Example 1 with sulfur. 1 .0 g of material from Example 1 and 6 g of sulfur are homogeneously mixed and heated at 180°C in an open apparatus for 6 hours. This gives 5.3 g of a solid dark gray substance which was milled to a fine powder by means of a ball mill.

Elemental analysis:

C = 6.6% by weight

S = 83% by weight

Example 4: Loading of the material from Example 2 with sulfur.

1 .0 g of material from Example 2 and 6 g of sulfur are homogeneously mixed and heated at 180°C in an open apparatus for 6 hours. This gives 5.7 g of a porous dark gray substance which was milled to a fine powder by means of a ball mill. Elemental analysis:

C = 12.5% by weight

S = 86% by weight

Example 5: Production of an electrochemical cell according to the invention (electrode)

2.30 g of material from Example 3 or 4, 0.80 g of Super P, 0.1 1 g of KS 6, 0.15 g of Celvol binder are mixed together. The mixture is dispersed in a solvent mixture of 65% of H₂0, 30% of isopropanol, 5% of 1 -methoxy-2-propanol. The dispersion was stirred for 10 hours.

The dispersion is applied by means of a doctor blade to Al foil and dried at 40°C under reduced pressure for 10 hours.

Example 6: Production of a benchmark electrochemical cell 3.310 g of sulfur, 2.39 g of Super P, 0.19 g of KS 6, 0.25 g of Celvol binder are mixed together. The mixture is dispersed in a solvent mixture of 65% of H₂0, 30% of isopropanol, 5% of 1 -methoxy-2-propanol. The dispersion is stirred for 10 hours. Example 7: Testing of the electrochemical cell according to the invention

For the electrochemical characterization of the composite, an electrochemical cell is built. Anode: Li foil 50 μηη thick, separator Tonen 15 μηη thick, cathode with composite material as described above. Electrolyte: 8% by weight of LiTFSI (LiN(S0₂CF₃)₂), 4% by weight of LiN0₃, 44% by weight of dioxolane and 44% by weight of dimethoxyethane.

Charging and discharging of the cell is carried out at a current of 7.50 mA in the potential range 1.8-2.5. The cell capacity was 75.1 mAh. Results are summarized n Table 1 .

Table 1

Sample Capacity Capacity

5th cycle [mAh/g S] 50th cycle [mAh/g S]

Example 6 850 800

Example 5 1 120 950

(material from

Example 3)

Example 5 1 130 950

(material from

Example 4)

Claims

A process for producing a carbon-comprising composite, which comprises the step

(a) pyrolysis of a porous metal-organic framework comprising at least one at least bidentate organic compound coordinated to at least one metal ion under a protective gas atmosphere, where the at least one at least bidentate organic compound is nitrogen-free.

The process according to claim 1 , wherein the pyrolysis is carried out at at least 500°C.

The process according to claim 1 or 2, wherein the protective gas atmosphere comprises nitrogen.

The process according to any of claims 1 to 3, wherein the at least one metal ion is an ion selected from the group of metals consisting of Mg, Al, Zr, Ti, V, Cr, Mo, Fe, Co, Cu, Ni and Zn.

The process according to any of claims 1 to 4, wherein the nitrogen-free at least one at least bidentate organic compound is derived from a dicarboxylic, tricarboxylic or tetracarboxylic acid.

The process according to any of claims 1 to 5, which comprises the further step

(b) at least partial removal of one or more metal components from the composite obtained in step (a).

The process according to claim 6, wherein the one or more metal components comprise at least one metal oxide.

The process according to claim 6 or 7, wherein the at least partial removal is carried out by washing out by means of an alkaline or acidic liquid.

9. The process according to any of claims 1 to 8, which comprises the further step

(c) impregnation of the composite obtained from step (a) or (b) with sulfur.

10. The process according to claim 9, wherein the impregnation is carried out by mixing and subsequent heating.

1 1 . The process according to claim 9 or 10, wherein the sulfur is used as solid or in solution.

12. A composite which can be obtained by a process according to any of claims 1 to 1 1 .

13. The use of a composite which can be obtained by a process according to any of claims 1 to 1 1 for the absorption of at least one material for the purpose of storage, removal, controlled release, chemical reaction of the at least one material or as support.

14. A sulfur electrode comprising a composite which can be obtained by a process according to any of claims 9 to 1 1 .

15. The use of a sulfur electrode according to claim 14 in an Li-sulfur battery.