CN115850717B - Sm-MOF, catalyst containing Sm-MOF and use thereof in preparing base oil from coal tar tail oil - Google Patents

Abstract

The application discloses a Sm metal organic framework, the chemical formula of which is [ SmNa (BDT) (H) ₂ O) ₃ ]·2H ₂ O, wherein BDT represents 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole with four carboxyl hydrogen atoms removed. The application also discloses an Sm metal organic frame and gamma-Al ₂ O ₃ The composite carrier and the catalyst formed by the composite carrier and active metal can be used for synthesizing lubricating oil base oil by taking coal tar tail oil as a raw material.

Description

Sm-MOF, catalyst containing Sm-MOF and use thereof in preparing base oil from coal tar tail oil

Technical Field

The application belongs to the field of catalysts, and particularly relates to a Sm-MOF, a carrier containing the Sm-MOF, a catalyst and application of the catalyst in preparing lubricating oil base oil by using coal tar tail oil as a raw material.

Background

It is well known that base oils are the main component of lubricating oils, and that national base oils (i.e., lubricating oil base oils) can be generally classified into 5 types, and base oils having a higher sulfur content and a lower viscosity index by extraction are called type I base oils; base oils obtained by modifying the molecular structure of mineral oils by chemical reactions are known as group II base oils; the base oil with higher viscosity index and lower volatility obtained by the combination process is called III base oil; the IV base oil is a kind of poly alpha-olefin (PAO) synthetic oil which does not contain sulfur, phosphorus, metal and wax and has poor boundary lubricity, and is synthesized by synthetic hydrocarbon, lipid, silicone oil, vegetable oil and reclaimed oil. Certain specific group III basestocks are comparable to group IV basestocks.

With the continuous development of science and technology, the demand and quality of essential base oil for industries such as automobiles, machinery, metallurgy, electric power, ships, aerospace and the like are continuously improved. According to statistics, the lubricating oil consumption of China in 2020 is about 1200 ten thousand tons, and the lubricating oil demand is continuously improved to promote the vigorous development of the base oil industry, wherein the lubricating oil consumption is 15% of the total world. The base oil is obtained by a specific catalyst and process, and the selection of the catalyst and process directly affects the quality and yield of the base oil. Thus, catalyst research and process exploration in base oil production are one of the current research hotspots.

For example, patent publication number CN1448480a describes that SAPO-11 molecular sieve and alumina are used as main carriers, group VIII element is used as active metal component, and organic amine is used to pretreat the catalyst carrier to improve the coverage condition of the active metal component to the acid center, so as to prepare the heterogeneous dewaxing catalyst with high selectivity and high stability. Patent publication number CN105214717a discloses that an isomorphous alkaline earth metal modified molecular sieve having TON or MTT topology structure and active alumina act together as a carrier, ammonium salt is used as a modifying substance, noble metal in group VIII metal is used as an active metal, and an isomerization dewaxing catalyst is obtained by an ion exchange modification method and an impregnation method. Patent publication No. CN106554817A, CN106554820A adopts ZSM-shaped cracking molecular sieve and silica-alumina as carriers, nickel, cobalt, molybdenum and tungsten as active metal elements, and the low pour point base oil is synthesized and produced through certain modification. Patent publication No. CN108102698A discloses a novel low pour point lubricant base oil catalyst synthesized by taking a rare earth element doped modified TON type molecular sieve and an inorganic refractory oxide as carriers and noble metal as an active component. Patent publication No. CN114471680A discloses a preparation method of a lubricating oil base oil catalyst, which is obtained by using a ten-membered ring structured molecular sieve and an amorphous inorganic porous material as a carrier and using VII group metal and/or VIII group metal (Pt, pd, ru, ir and Re) as active metals in an environment with a pH value of 6-8. Patent publication number CN 104803899a discloses a complex formed by reacting iron, cobalt or nickel with specific organic compounds as a catalyst for the direct synthesis of lubricating base oils from ethylene. Patent publication number CN1803998A discloses a dewaxing catalyst comprising a composite molecular sieve, which is a molecular sieve having a large pore structure and contains non-framework silicon. Patent publication number CN110841724a discloses a method for producing high-quality lubricating oil base oil by using a combination catalyst, wherein the combination catalyst is a first catalyst and a second catalyst, the first catalyst and the second catalyst both contain a molecular sieve with a ten-membered ring mesoporous structure, and the molar ratio of silicon oxide to aluminum oxide in the molecular sieve is 120-300; pt and Pd in the group VIII metal are used as active metal components. Patent publication number CN113677778A discloses a method for producing a lubricating base oil, wherein the catalyst is a catalyst in which 1 or more metals selected from the group consisting of group 6, group 8, group 9 and group 10 elements of the periodic table are supported on an inorganic oxide carrier having a total acid site amount of 0.5mmol/g or more as measured by an ammonia temperature programmed desorption method. Patent publication number CN112126465a discloses a hydrogenation catalyst composition and a method for preparing lubricating oil base oil by fischer-tropsch synthesis of wax, which comprises three types of catalysts, namely a hydrogenation pretreatment catalyst, a combination catalyst and a hydrofining catalyst, wherein the hydrogenation pretreatment catalyst is prepared from inorganic oxide as a carrier, cobalt, nickel, molybdenum and tungsten as active metals, and nitrogen, silicon, sulfur and boron as auxiliary agents; the hydrogenation combined catalyst is formed by combining two catalysts, namely a catalyst A and a catalyst B, wherein the catalyst A takes a molecular sieve with a MEL structure as a carrier, active noble metals (platinum, palladium and iridium) are loaded, and the catalyst B takes a molecular sieve with an MTW structure as a carrier, and active noble metals (platinum, palladium and iridium) are loaded; the hydrofining catalyst uses heat-resistant inorganic oxide as a carrier, metal elements such as platinum, palladium, iridium and the like as active metals, and elements such as cobalt, nickel, molybdenum, tungsten and the like as a hybridization auxiliary agent. Patent publication number CN113072973a discloses a method for producing a lubricating base oil, which comprises five steps, respectively: (1) hydrocracking, (2) hydroisomerization, (3) hydrofinishing, (4) clay refining, and (5) recycling. The hydrofining catalyst adopts a modified Y-type molecular sieve as a carrier, and one or more of Mo, W, co or Ni are active metals; the isomerization dewaxing catalyst is an aluminum phosphate molecular sieve catalyst loaded with noble metals; the supplementary refining catalyst takes alumina or silicon oxide as a carrier and carries one or more noble metals of platinum, palladium and iridium; patent publication number CN102333592B discloses a hydroisomerization catalyst and a method for producing the catalyst, as well as a dewaxing method for hydrocarbon oils and a method for producing lubricant base oils. The hydroisomerization catalyst is formed by taking ion exchange zeolite and inorganic oxide as carriers and loading transition metal, molybdenum and tungsten. Patent publication nos. CN1853780A, CN1853779A, CN1853781A, CN1872959a and CN1872960a disclose a catalyst containing an organic additive, wherein the molar ratio of the organic additive to the sum of the hydrogenation active metal components in terms of oxide is 0.03-2:1, preferably 0.08-1.5:1. Patent publication nos. CN1488733A, CN1448480A, CN1289643A, CN1228357A, CN1803998A, CN1382526a and CN101191082a disclose an isomerisation pour point depressing catalyst having good wax hydroisomerisation reaction properties. As can be seen, various catalysts for the production of lube base oils by isodewaxing have been studied and developed, but most of these studies have focused on petroleum-based hydrocracking tail oil isodewaxing or fischer-tropsch synthesis isodewaxing processes. At present, no document reports a process for producing lubricating oil base oil by taking coal tar hydrocracking tail oil as a raw material to carry out isomerization dewaxing. The existing process for producing lubricating oil base oil by taking coal tar hydrocracking tail oil as a raw material has the following problems: because the components of the coal tar hydrogenated tail oil are complex, the catalyst used in the process has short service life, few active sites, great influence of pH value, poor selectivity, narrow reaction temperature and the like.

Metal-organic frameworks (MOFs) are a class of crystalline materials composed of organic molecules and metals or metal clusters connected, which have been increasingly used in photocatalysis and electrocatalysis due to their large specific surface area, diverse structural topology, and rich active centers. In particular, the metal-organic framework can be used as a carrier of a catalyst (for example, active metal), or mixed with other carriers to be used as a carrier of the catalyst, and has the advantages of improving the property of the catalyst or increasing the catalytic effect of the catalyst.

Disclosure of Invention

An object of one aspect of the present application is to provide a Sm metal organic framework (Sm-MOF) which is a Sm metal coordination polymer of the formula [ SmNa (BDT) (H) ₂ O) ₃ ]·2H ₂ O, wherein BDT represents 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole with four carboxyl hydrogen atoms removed.

The Sm metal organic frame belongs to monoclinic system, and the space group is P2 ₁ /n， α＝γ＝90°，β＝93.772(9)。

The Sm metal organic frameUnit cell volume

The number of molecules in the unit cell of the Sm metal organic framework is z=4.

The thermal gravimetric analysis curve of the Sm metal organic frame comprises a first-stage weightlessness at 40-220 ℃ and a second-stage weightlessness at 480-700 ℃.

The application also provides a preparation method of the Sm metal organic framework, which comprises the following steps: samarium chloride and 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole were synthesized by hydrothermal synthesis in isopropanol and acetic acid/sodium acetate buffer at ph=6.

In a preferred embodiment of the application, the hydrothermal synthesis comprises the steps of heating the reaction liquid in a stepwise manner, then cooling the reaction liquid in a stepwise manner, wherein the step heating process is to heat the reaction liquid from room temperature to 100-130 ℃ for 5-7 hours, then heating the reaction liquid to 150-170 ℃ for 2-4 hours after keeping the temperature for 10-14 hours, and keeping the temperature for 65-80 hours. The cooling process of the stepped section is to cool the reaction liquid from 160-170 ℃ to room temperature at the speed of 2-4 ℃/h.

In a preferred embodiment of the application, the molar ratio of samarium chloride to 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole in the reaction mixture is 1.0:0.8-1.2.

In a preferred embodiment of the application, the volume ratio of isopropanol to acetic acid/sodium acetate buffer in the reaction solution is 1:4-6.

In another aspect, the present application provides a composite support comprising a Sm metal organic framework and gamma-Al ₂ O ₃ Wherein the Sm metal organic framework and gamma-Al ₂ O ₃ The weight ratio of (2) to (3) is 1:2-15, more preferably 1:4-12, still more preferably 1:9.

In still another aspect, the present application provides a method for preparing the above catalyst, which comprises the steps of:

(1) The Sm metal organic frame and gamma-Al ₂ O ₃ Is mixed according to the weight ratio of 1:2-15Adding solvent to form viscous fluid, extruding the viscous fluid to form and drying;

(2) And (3) roasting the molded solid obtained in the step (1) at 400-480 ℃ for 3-6 hours to obtain the composite carrier.

The solvent can be selected from water or aqueous solution of citric acid with mass concentration of 0.1% -1%. In some embodiments of the application, the solvent is selected from water.

In yet another aspect, the present application provides a catalyst comprising the composite support described above and an active metal selected from platinum, pd, ni, mo, co, or a combination thereof, wherein the active metal is supported in an amount of 0.1 to 0.8% by weight.

In some preferred embodiments of the application, the loading of active metal is from 0.2 to 0.4% by weight.

In still another aspect, the present application provides a method for preparing the above catalyst, which comprises the steps of:

(1) The Sm metal organic frame and gamma-Al ₂ O ₃ Mixing according to the weight ratio of 1:2-15, adding solvent to form viscous fluid, extruding the viscous fluid to form, and drying;

(2) Roasting the formed solid obtained in the step (1) at 400-480 ℃ for 3-6 hours to obtain the composite carrier,

(3) And loading active metal on the composite carrier by an impregnation method to obtain the catalyst.

The solvent may be selected from water.

In a further aspect, the application provides the use of the catalyst in preparing lubricating oil base oil from coal tar tail oil.

In some embodiments of the present application, the method for preparing a lubricant base oil from coal tar tail oil using the catalyst comprises the steps of:

(1) And (3) at 280-350 ℃, utilizing the catalyst to carry out isomerization dewaxing on the coal tar tail oil after catalytic hydrogenation.

The application utilizes Sm metal organic framework and gamma-Al ₂ O ₃ Is a carrier, loaded withThe catalyst formed by the active metal can lead the coal tar tail oil after catalytic hydrogenation to be dewaxed in an isomerism way to generate the base oil of lubricating oil, thereby improving the utilization of coal tar in China.

1kg of the catalyst can accumulatively catalyze 4t to 5t of coal tar tail oil to carry out isomerization dewaxing.

Drawings

FIG. 1 (a=) is a diagram of the coordination environment of the Sm-MOF of the present application, from which it can be seen that each asymmetric unit comprises an independently crystallized Sm ³⁺ One Na ⁺ One BDT ligand, three coordinated water molecules, and Sm ³⁺ Coordinated with four ligands, two water molecules. The structure is as follows: six carboxyloxies exist in a chelate form with Sml, and simultaneously O5, O7 and O2 are used as bridging, and the O5 and the O7 are used as bridging oxygen to form Na1 into a heteronuclear bimetallic unit, na ⁺ The ion forms a five-coordinate configuration with 1 oxygen (O5) in the water molecule and 4 atoms in the BDT 4-ligand, 3 BDT of which ^4- The on-board oxygen O2, O7, O11 and 1 BDT 4-N atoms in the ligand are all bridged coordination. The carboxyl group where O2 is located serves as a bridging carboxyl group to connect the heteronuclear bimetallic units into a one-dimensional chain.

FIG. 1 (b) is a two-dimensional network of Sm-MOFs; FIG. 1 (c) is a diagram of a Sm-MOF three-dimensional supramolecular structure; FIG. 1 (d) is a diagram showing the topology of Sm-MOF. From the diagrams (b) to (c), it can be seen that the two-dimensional two-layer planar structure is formed by passing a one-dimensional chain through the flexible BDT ^4- Linking to form, through BDT ^4- The three-dimensional structure is expanded into a three-dimensional structure, the formed three-dimensional structure has a certain pore structure, and meanwhile, the stability of the three-dimensional structure is improved due to the existence of an N-Na bond formed by N1 and Na 1.

FIG. 2 is a thermogravimetric analysis of Sm-MOF from which it can be seen that the thermogravimetric analysis of Sm-MOF includes a first stage weight loss of 40-220℃and a second stage weight loss of 480-700 ℃.

FIG. 3 is an infrared spectrum of Sm-MOF, from which it can be seen that the characteristic absorption peak of carbonyl symmetry v s (COO-) appears at 1413cm-1 and that the carbonyl asymmetry vas (COO-) stretches at 1560cm ^-1 And 1627cm ^-1 The presence of the site.

FIG. 4 is a process flow diagram of a pre-hydrogenation and isodewaxing of coal tar tail oil, wherein (1) represents a coal tar tail oil surge tank; (2) represents a coal tar tail oil pressurizing pump; (3) a heater; (4) represents a pre-hydrogenation reactor (R1); (5) represents isodewaxing feed and discharge heat exchanger (E1): (6) represents an isodewaxing feed furnace (F1); (7) Representing an isomerization dewaxing reactor (R2), the catalyst of the application is placed in the R2 to catalyze the pre-hydrogenated coal tar tail oil to carry out isomerization dewaxing.

FIG. 5 is a graph of Sm-MOF and gamma-Al in different weight ratios ₂ O ₃ Viscosity index and pour point profile of lube base oil formed from pre-hydrogenated coal tar tail oil catalyzed by platinum-supported catalyst.

FIG. 6 is a graph of the coordination environment for Sm-MOF prepared in example 7 of the present application, having the chemical formula [ Sm (BDT) (H) ₂ O) ₃ ]·H ₂ O。

Detailed Description

The inventors of the present application have conducted intensive studies to prepare a novel Sm metal coordination polymer, namely Sm-MOF, which can be used in combination with gamma-Al ₂ O ₃ A novel carrier is formed, and after active metals are loaded on the carrier by an impregnation method, the catalyst capable of catalyzing coal tar tail oil to form lubricating oil base oil is formed. The catalyst has the advantages of more active sites, good selectivity and wide reaction temperature. The present application has been completed on the basis of this finding.

Synthesis and characterization of Sm-MOF

The Sm-MOF of the application is a Sm metal coordination polymer with a chemical formula of [ SmNa (BDT) (H) ₂ O) ₃ ]·2H ₂ O, wherein BDT represents 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole with four carboxyl hydrogen atoms removed, H ₄ The BDT structure is shown below:

the Sm-MOF of the application belongs to monoclinic system, and the space group is P2 ₁ N, α=γ=90°, β= 93.772 (9). Thermal fractionation of Sm-MOFs of the applicationThe analysis curve comprises a first-stage weight loss of 40-220 ℃ and a second-stage weight loss of 480-700 ℃, wherein the first-stage weight loss mainly comprises the loss of free water and crystal water of materials, and the second-stage weight loss mainly comprises structural collapse.

The Sm-MOF is synthesized by a hydrothermal synthesis method. In one embodiment of the application, the Sm-MOF is synthesized as follows:

samarium chloride (SmCl) ₃ ) 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole (H) ₄ BDT) is dissolved in the mixed solution of isopropanol and buffer reagent (acetic acid/sodium acetate) with pH=6 according to the proportion of 1:1, the solution is stirred for 10-15min at room temperature, then the mixed solution is added into a high-pressure reaction kettle with polytetrafluoroethylene lining, the temperature is gradually raised to 160 ℃ by using a stepped temperature raising mode, the temperature is kept for 72h, and then the temperature is lowered to the room temperature by using a temperature lowering program with the speed of 2-4 ℃/h. The temperature rising mode of the stepped section is that the solution is heated from 30 ℃ to 120 ℃ for 6 hours, the temperature is kept constant for 12 hours, then the temperature is raised to 160 ℃ for 2 hours, and the crystal is filtered and then is used for H ₂ O and ethanol are washed, purified and dried to obtain light yellow rod-shaped crystals. The formulation method of the acetic acid/sodium acetate buffer agent with ph=6 is: 54.6g of anhydrous sodium acetate was taken, and after dissolving in 20ml of acetic acid solution of 1mol/L, water was added to dilute to 500ml.

Composite carrier and synthesis thereof

The composite carrier of the application comprises a Sm metal organic framework and gamma-Al ₂ O ₃ Wherein the Sm metal organic framework and gamma-Al ₂ O ₃ The weight ratio of (2) to (3) is 1:2-15, more preferably 1:4-12. For example, sm metal organic frameworks and gamma-Al ₂ O ₃ The weight ratio is 1:4, 1:7, 1:9, 1:12, etc.

The composite carrier of the application can be prepared by the following steps:

(1) Coordination polymer of Sm metal and gamma-Al ₂ O ₃ Mixing according to the weight ratio of 1:2-15, adding solvent to form viscous fluid, extruding the viscous fluid to form, and drying;

(2) And (3) roasting the molded solid obtained in the step (1) at 400-480 ℃ for 3-6 hours in the presence of air to obtain the composite carrier.

To ensure the stability of Sm-MOF, the firing temperature should not be higher than 480 ℃.

Such solvents include, but are not limited to, water.

In one embodiment of the present application, the composition contains Sm metal coordination polymer and gamma-Al ₂ O ₃ The viscous fluid of (a) is formed by extrusion molding, dried to form a trilobal shaped body, and then the trilobal shaped body is baked at 430 ℃ in the presence of air, thereby obtaining a carrier baked by a heat history of heating at 350 ℃ or higher.

Catalyst and synthesis thereof

The catalyst of the present application comprises the above composite support and an active metal including, but not limited to, group VIII metals (e.g., pt and Pd) and transition metals (Ni, mo, co), the amount of noble metal supported in the catalyst being about 0.1 to 0.8%, such as about 0.2%, about 0.3%, about 0.4%, about 0.5%, etc., by weight. The catalyst of the present application is formed by supporting a group VIII metal (e.g., platinum) on the above composite support by a conventional impregnation method.

Isomerization dewaxing of coal tar tail oil

The principle of using the catalyst of the application to carry out isomerization dewaxing on coal tar tail oil to prepare lubricating oil base oil is as follows: the catalyst is composed of a carrier with a special pore structure and a supported noble metal, and follows a catalytic mechanism of a metal acid center. The metal site is Pt metal, and the acid center is a carrier containing Sm-MOF. The alkane molecule is dehydrogenated on the metal position to obtain alkene, further the alkene is formed on the acid center through a protonation reaction, the carbonium ion undergoes rearrangement isomerism or a cracking reaction, and then the carbonium ion is deprotonated to form alkene. The olefin molecules are hydrogenated on the metal site to obtain isoparaffins. In the reaction process, the metal site and the acid center play an important role respectively, the dehydrogenation and hydrogenation processes of normal paraffins are carried out on the metal site, and the isomerization and cracking processes of normal carbon ions are carried out on the acid center. The isomerization dewaxing catalyst has optimal reactivity when the acidic function of the acid center is in equilibrium with the dehydrogenation/hydrogenation activity of the metal site.

Dipping method

The present application provides a method for supporting active metal on a composite carrier by impregnation method, which is a method commonly used in the art ([ 1 ]]Zhang Jiguang catalyst preparation Process technique [ M]Chinese petrochemical publishing agency, 2019: 11; [2]Wang Jianguo, zhang Jiayu, pang Li, impregnation method for preparing Pt/Al ₂ O ₃ Investigation of the catalyst-Effect of competing adsorbents on Pt distribution [ J]Chemical chemistry journal, 1982 (02): 151-159. ). In a specific embodiment of the present application, the specific process of loading the active metal on the composite carrier is: soaking (impregnating) the prepared carrier in a solution containing 0.04-0.06 mol/LH ₂ PtCl ₆ And 0.3-0.5 mol/L citric acid water solution, filtering to remove excessive solution after adsorption balance, drying and activating to obtain the catalyst finished product. The Pt loading is controlled by the concentration and volume of the impregnating solution.

In the description of the present application, "room temperature" means 0 to 40 ℃. For example, 10 to 30℃and 20 to 30 ℃.

In the description of the application, "coal tar tail oil" is also referred to as "coal tar hydrogenated tail oil" or "coal tar hydrocracked tail oil".

The application will be further illustrated with reference to specific examples. The specific embodiment is implemented on the premise of the technical scheme of the application, and detailed implementation modes and operation processes are given. It is to be understood that these examples are illustrative of the present application and are not intended to limit the scope of the present application. The experimental procedure, in which no specific conditions are noted in the examples below, is generally carried out according to conventional conditions. Unless otherwise indicated, proportions and percentages are by weight.

The following examples used an electrothermal constant temperature forced air drying oven (DHG-9145 AF) manufactured by Shanghai and Instrument manufacturing Co., ltd.) to synthesize Sm-MOF by hydrothermal synthesis. The required agent was weighed using an analytical balance (Secura 125-1 CN) manufactured by Sidoris, germany.

Example 1

1.1 Synthesis of Sm-MOF

Samarium chloride (SmCl) ₃ ) 3, 5-di(3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole was dissolved in isopropyl alcohol and acetic acid/sodium acetate buffer agent with pH=6 in a ratio of 1:1 (the preparation method of the acetic acid/sodium acetate buffer agent comprises the steps of taking 54.6g of anhydrous sodium acetate, adding 20ml of 1mol/L acetic acid solution for dissolution, adding water for dilution to 500 ml), wherein the volume ratio of isopropyl alcohol and buffer agent is 1:5.5, and specific details of the used reagents are shown in Table 1. Stirring the obtained solution at room temperature for 13min, adding the solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining, gradually heating to 160 ℃ by using a stepped heating mode, keeping the temperature for 72h, and then cooling to room temperature by using a cooling program at a speed of 2-4 ℃/h. The temperature rising mode of the stepped section is that the solution is heated from 30 ℃ to 120 ℃ for 6 hours, the temperature is kept constant for 12 hours, then the temperature is raised to 160 ℃ for 2 hours, and the crystal is filtered and then is used for H ₂ O and ethanol are washed, purified and dried to obtain light yellow rod-shaped crystals.

TABLE 1 major reagents for Sm-MOF Synthesis

Monocrystalline particles with regular morphology and high crystallinity were selected by means of an optical microscope (SZ 680, chongqing ott optical instruments, inc.). At 296K, the colorless bulk crystals were irradiated by Mo-K.alpha.of Bruker D8 Venture ) Single crystal diffraction data for the crystals were obtained and absorption correction was performed on the collected data using the SCALE3 absjack program. Pass F using SHELXL-97 package and full matrix ² The least square method optimizes the data. Simultaneously, the SQUEZE procedure is used for preparing solvents DMF and H in the mesoporous of the formed crystals ₂ And (5) carrying out treatment on the O molecules. All the above calculations were performed in the SHELXTL system.

Characterization results show that Sm-MOF is a three-dimensional structure, and the asymmetric unit comprises an independent crystal Sm ³⁺ One Na ⁺ One BDT ligand, three coordinated water molecules, sm ³⁺ Coordinated to four ligands, two water molecules, see figure 1 (a). From this figure it can be seen that six carboxyoxygens chelate with Sml, where O5, O7, O1 are used as bridging and O5, O7 as bridging oxygens connect Na1 to form heteronuclear bimetallic units. The carboxyl where O1 is located is used as bridging carboxyl to connect heteronuclear bimetallic units into a one-dimensional chain, and the one-dimensional chain passes through a flexible ligand H ₄ The BDT connection forms a two-dimensional double-layer plane, see (b) diagram in FIG. 1, and further expands into a three-dimensional structure, see (c) diagram in FIG. 1. The Sm-O bond length range in the Sm-MOF is as follows:the Na-O bond length ranges from: />And the Na-N bond length ranges from: />The bond angle range of O-Sm-O is: 51.3 (2) ° -159.9 (3) °, the bond angle range of O-Na-O being: 76.11 (13) ° to 162.5 (4) °, the bond angle range of O-Na-N being: 89.41 (19) ° to 107.9 (3) °, sm-O bond length and O-Sm-O bond angle in the heteronuclear bimetallic Sm (Na) -MOF were equal to those of the prior art (Liu, xinfang; zhang, xiaoyu; li, rongafang; du, liyong; feng, xun; ding, yuqiang. A highly sensitive and selective "tum off-on" fluorescent sensor based on Sm-MOF for the detection of tertiary butylhydroquinone [ J)]Dyes and Pigments,2020,178, 108347) are consistent with the ranges reported. The crystallographic data of Sm-MOFs of the present application are set forth in tables 2-1, 2-2 and 2-3. (Table 2-1 shows the crystallographic data of the complexes, table 2-2 shows the bond lengths of Sm-MOF; table 2-3 shows the bond angles of Sm-MOF). The Sm-MOF infrared spectrum of the present application is shown in FIG. 3, from which it can be seen that the carbonyl symmetry vs (COO-) feature absorbsPeaks appear at 1413cm-1 and carbonyl-asymmetric vs (COO-) stretches at 1560cm-1 and 1627 cm-1. The thermogravimetric analysis curve of the MOF material comprises a first-stage weight loss of 40-220 ℃ and a second-stage weight loss of 480-700 ℃, wherein the first-stage weight loss mainly comprises the loss of free water and crystal water of the material, and the second-stage weight loss mainly comprises structural collapse.

Table 2-1 Crystal data of the Complex

TABLE 2 bond lengths of 2-Sm-MOF

TABLE 2 bond angles of 3-Sm-MOF

Symmetry transformations used to generate equivalent atoms：Symmetry transformations used to generate equivalent atoms#1：-x+3/2,y-1/2,-z+3/2；#2：-x+1,-y+1,-z+1：#3：-x+3/2,y-1/2,-z+1/2；#4：x-1/2，-y+1/2，z-1/2#5：x+l/2,-y+1/2,z+1/2；#6：-x+3/2,y+1/2,-z+3/2；#7：-x+3/2,y+1/2,-z+1/2

1.2 catalyst Synthesis

In Sm-MOF ([ SmNa (BDT) (H) ₂ O) ₃ ]·2H ₂ O) and an inorganic oxide gamma-Al ₂ O ₃ Is a composite carrier, and the proportion is 1:4, loading platinum element in VIII group metal by a conventional impregnation method to obtain the required catalyst XL-1, wherein 0.3% of noble metal is loaded in the catalyst XL-1.

The synthesis steps of the catalyst are as follows:

(1) Sm-MOF and inorganic oxide gamma-Al ₂ O ₃ Mixing according to the proportion of 1:4, adding a proper amount of water, stirring to form a viscous fluid, extruding the viscous fluid to form a three-leaf shaped formed body, and drying;

(2) Roasting the leaf-shaped molded body for 4 hours at 430 ℃ under the condition of air, so as to obtain a carrier which is roasted by a heat history of heating above 350 ℃, wherein the roasting temperature is not higher than 480 ℃ to ensure the stability of Sm-MOF, and the composite carrier is prepared;

(3) Impregnating the prepared composite carrier with a solution containing 0.0554mol/LH ₂ PtCl ₆ And 0.4mol/L citric acid water solution, filtering out excessive solution after adsorption balance, drying, and activating to obtain catalyst finished product XL-1, wherein the load is controlled by the concentration and volume of the stain solution.

1.3 preparation of lubricating base oil by catalyzing coal tar tail oil

Feeding the synthesized catalyst XL-1 into an isomerization dewaxing reactor (R2); the tail oil enters a tail oil buffer tank, is pressurized to 15.0-17.0 MPa by a tail oil pressurizing pump and is mixed with hydrogen, is heated to 130-200 ℃ by a heat exchanger (3), enters a prehydrogenation reactor (R1) from the top and is subjected to aromatic hydrocarbon saturation hydrogenation, the reactor is provided with three sections of beds, cold hydrogen is arranged between every two sections to regulate temperature, wherein the reaction airspeed is 0.48, and the hydrogen-oil ratio is 200-300. Discharging the pre-hydrogenated product from the bottom of a pre-hydrogenation reactor (R1), wherein the temperature is 150-220 ℃, firstly, entering an isomerization feed-discharge heat exchanger (E1) to exchange heat with an isomerization dewaxing product to 252-325 ℃, then entering an isomerization feed furnace (F1) to heat to 280-350 ℃, finally entering an isomerization dewaxing reactor (R2) to carry out isomerization cracking reaction, setting a three-stage bed layer in the reactor, and setting cold hydrogen between two and three stages to carry out temperature adjustment, wherein the reaction space velocity is 1. The isomerization dewaxing product is cooled to 202-271 ℃ through heat exchange between E1 and the feed, and then enters a complementary refining reactor for refining reaction. The quality of the base oil produced is shown in table 3 below (where the appearance, acid number and pour point of the base oil are related to isodewaxing).

1kg of catalyst XL-1 of the example can accumulatively catalyze 4t of coal tar tail oil to carry out isomerization dewaxing.

Table 3 quality of base oils produced

Examples 2 to 4

The synthesized Sm-MOF of example 1 was combined with gamma-Al ₂ O ₃ After mixing in weight ratios of 1:7, 1:9 and 1:12, respectively, catalysts 2 to 4 were synthesized (the synthesis procedure and conditions of the catalyst were the same as 1.2 of example 1), wherein the weight percentage of the platinum supported on the catalyst was 0.3%. The catalysts synthesized in examples 2-4 were designated XL-2, XL-3, XL-4, respectively.

Lubricating oil base oils were prepared using catalysts XL-2, XL-3, XL-4 to catalyze the coal tar tail oil according to the conditions and procedure of 1.3 of example 1, and the quality of the base oils produced are shown in tables 4-6 below.

TABLE 4 quality of base oils produced in example 2

TABLE 5 quality of base oils produced in example 3

TABLE 6 quality of base oils produced in example 4

Example 5

5.1 catalyst XL-5

The carrier is selected from inorganic oxide gamma-Al ₂ O ₃ By a common wayThe platinum element in the VIII group metal is loaded by a conventional impregnation method to obtain the required catalyst, and 0.3 percent of noble metal is loaded in the catalyst.

The synthesis steps of the catalyst XL-5 are as follows:

(1) gamma-Al of inorganic oxide ₂ O ₃ Adding a proper amount of water, stirring to form a viscous fluid, extruding the viscous fluid to form a three-leaf-shaped formed body, and drying;

(2) Roasting the formed solid obtained in the step (1) at 430 ℃ under the condition of air;

(3) gamma-Al ₂ O ₃ Soaking the carrier in a solution containing 0.0554mol/LH ₂ PtCl ₆ And 0.4mol/L citric acid water solution, filtering out excessive solution after adsorption balance, drying, and activating to obtain catalyst finished product XL-5, wherein the load is controlled by the concentration and volume of the stain solution.

5.2 lubricating oil base oils were prepared using catalyst XL-5 to catalyze coal tar tail oils according to the conditions and procedure of 1.3 of example 1, the quality of the base oils produced being shown in Table 7 below.

TABLE 7 quality of base oils produced in example 5

Example 6

6.1 Sm-MOF synthesis

Samarium chloride (SmCl) ₃ ) 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole is dissolved in isopropanol and acetic acid/sodium acetate buffer agent with pH=6 according to the proportion of 1:1 (the preparation method is as in example 1), wherein the volume ratio of isopropanol to buffer agent is 1:6, the obtained solution is stirred at room temperature for 14min, then the obtained solution is added into a high-pressure reaction kettle with polytetrafluoroethylene lining, the temperature is gradually raised to 170 ℃ by using a stepped heating mode, the temperature is kept constant for 70H, and then the temperature is reduced to the room temperature by using a cooling program with the speed of 2-4 ℃/H. Wherein the temperature rising mode of the stepped section is that the reaction liquid is heated from 30 ℃ to 130 ℃ for 5.5 hours, and the reaction liquid is kept at the constant temperature for 12 hours and then is subjected to 2.5 hoursHeating to 170 ℃, filtering the crystals, and then using H ₂ O and ethanol were washed, purified and dried to obtain pale yellow rod-like crystals (the structure was the same as that of Sm-MOF synthesized in example 1).

6.2 catalyst XL-6

In Sm-MOF ({ [ SmNa (BDT) (H) ₂ O) ₃ ]·2H ₂ O } n) and an inorganic oxide gamma-Al ₂ O ₃ Is a composite carrier with the proportion of 1:9, and the platinum element in the VIII group metal is loaded by a conventional dipping method to obtain the required catalyst, wherein 0.5 percent of noble metal is loaded in the catalyst.

The synthesis steps of the catalyst XL-6 are as follows:

(1) Sm-MOF and inorganic oxide gamma-Al ₂ O ₃ Mixing according to the proportion of 1:9, adding a proper amount of water, stirring to form a viscous fluid, extruding the viscous fluid to form a three-leaf-shaped formed body, and drying;

(2) Roasting the leaf-shaped formed body for 3h at 430 ℃ under the condition of air;

(3) gamma-Al ₂ O ₃ Soaking and impregnating the carrier in H containing 0.06mol/L ₂ PtCl ₆ And 0.5mol/L citric acid, filtering out excessive solution after adsorption equilibrium, drying, and activating to obtain the catalyst finished product XL-6.

2.3 preparation of lubricating base oil by catalyzing coal tar tail oil

The process is the same as that of 1.3 of the example 1, and 1kg of catalyst XL-6 can accumulatively catalyze 5t of coal tar tail oil to carry out isomerization dewaxing, so that the catalytic amount per unit time is increased. The quality of the base oil produced is shown in table 8 below.

TABLE 8 quality of base oils produced in example 6

Example 7

7.1 samarium chloride (SmCl) ₃ ) 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole was dissolved in isopropanol and buffer at pH=6 in a 1:1 ratioIn the reagent (acetic acid/sodium acetate), the volume ratio of isopropanol to buffer reagent is 1:4, the obtained solution is stirred at room temperature for 11min, then the solution is added into a high-pressure reaction kettle with polytetrafluoroethylene lining, gradually heated to 160 ℃ by using a stepped heating mode, kept at a constant temperature for 74h, and then cooled to room temperature by using a cooling program at a speed of 2-4 ℃/h. Wherein the temperature rising mode of the stepped section is that the reaction liquid is heated from 30 ℃ to 130 ℃ for 5.5 hours, the temperature is kept constant for 12 hours, then the temperature is raised to 170 ℃ for 2.5 hours, the crystal is filtered and then is used for H ₂ O and ethanol to obtain pale yellow flaky crystals (the coordination environment diagram of which is shown in figure 6). The metal element in the Sm-MOF contains Sm element only, does not contain Na, and has a chemical formula of [ Sm (BDT) (H) ₂ O) ₃ ]·2H ₂ O。

7.2 catalyst Synthesis

With Sm-MOF ([ Sm (BDT) (H) ₂ O) ₃ ].2H ₂ O) and an inorganic oxide gamma-Al ₂ O ₃ The platinum element in the group VIII metal was supported by the impregnation method of example 1 in a ratio of 1:9 to obtain the desired catalyst, in which 0.3% of the noble metal was supported.

The synthesis steps of the catalyst are as follows:

(1) Mixing Sm-MOF containing Na with inorganic oxide gamma-Al ₂ O ₃ Mixing according to the proportion of 1:9, adding a proper amount of water, stirring to form a viscous fluid, extruding the viscous fluid to form a three-leaf-shaped formed body, and drying;

(2) Roasting the leaf-shaped molded body at 460 ℃ for 3h under the condition of air;

(3) Platinum was loaded according to 1.2 of example 1. The synthesized catalyst was designated XL-7.

7.3 preparation of lubricating base oil by catalyzing coal tar tail oil

The procedure was the same as in example 1, and the quality of the base oil produced is shown in Table 9 below.

TABLE 9 quality of base oils produced in example 7

As can be seen from example 7, under different preparation conditions, in particular, different amounts of buffer reagents, the amounts, polarities and pH values of the reactants of the solutions are changed, so that the molecular formulas of the obtained Sm coordination polymers are different, and the Sm coordination polymers prepared in the example do not contain Na and cannot form a double-gold heteronuclear bimetallic unit, and the coordination polymers also form a three-dimensional structure, but have unstable structure. Resulting in a decrease in the strength of the synthesized carrier.

It is well known that long-chain monocyclic aromatic compounds have a higher viscosity index than isoparaffins at the same congealing point. Sm-MOF and gamma-Al of the application ₂ O ₃ Besides providing skeleton support to strengthen mechanical strength, the composite carrier also plays a role in uniformly dispersing active components, even can provide acid sites such as B acid, L acid and the like, and can also become active centers of ring opening, cracking, isomerism and the like. By comparison, it was found (as shown in fig. 5) that in the process of preparing a lubricant base oil from coal tar tail oil as a raw material, the viscosity index of the base oil was in a decreasing trend as the Sm-MOF content in the catalyst was decreased, and the viscosity index was 102 when no Sm-MOF was contained. The reason may be that the rare earth Sm-MOF modified gamma-Al ₂ O ₃ The acid strength of the carrier is greatly improved. The special pore structure of Sm-MOF not only can provide more active sites and slow down collapse of the internal micropore structure, but also increases the isodewaxing activity of the catalyst due to the bifunctional catalyst formed by rare earth elements and noble metals in Sm-MOF.

Under the premise of considering economy and catalyst stability, sm-MOF and inorganic oxide gamma-Al are selected ₂ O ₃ The pour point of the base oil is the lowest at the ratio of 1:9, and the viscosity index is better at the ratio, so that the requirements of low pour point and better viscosity index of the base oil are met.

The foregoing description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application, and various modifications can be made to the above-described embodiment of the present application. All simple, equivalent changes and modifications made in accordance with the claims and the specification of this application fall within the scope of the patent claims. The present application is not described in detail in the conventional art.

Claims (14)

1. A Sm metal organic framework is characterized in that the Sm metal organic framework is a Sm metal coordination polymer, and the chemical formula is [ SmNa (BDT) (H) ₂ O) ₃ ]·2H ₂ O, wherein BDT represents 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole with four carboxyl hydrogen atoms removed,

the Sm metal organic framework belongs to a monoclinic system, and the space group is P2 ₁ /n， α＝γ＝90°，β＝93.772(9)。

2. The Sm metal organic framework of claim 1 wherein the Sm metal coordination polymer has a unit cell volume

The number of molecules in the unit cell of the Sm metal coordination polymer is z=4.

3. The Sm metal organic frame of claim 1, wherein the thermogravimetric analysis profile of the Sm metal organic frame comprises a first stage weight loss of 40-220 ℃ and a second stage weight loss of 480-700 ℃.

4. A method of producing the Sm metal organic framework according to any one of claims 1 to 3, characterized in that the method comprises the steps of:

samarium chloride and 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole are synthesized by a hydrothermal synthesis method in isopropyl alcohol and acetic acid/sodium acetate buffer solution with pH=6,

in the reaction solution, the volume ratio of the isopropanol to the buffer solution is 1:5.5-6.5.

5. The method for producing a Sm metal organic framework according to claim 4, characterized in that,

the hydrothermal synthesis comprises the steps of carrying out stepped heating and then stepped cooling on the reaction liquid, wherein the stepped heating process is that the reaction liquid is heated to 100-130 ℃ from room temperature after 5-7 hours, is heated to 150-170 ℃ after 10-14 hours of constant temperature, and is cooled to room temperature from 160-170 ℃ at a speed of 2-4 ℃/h after 2-4 hours of constant temperature, and is kept for 65-80 hours.

6. The method for producing Sm metal organic framework according to claim 4, wherein the molar ratio of samarium chloride to 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole in the reaction solution is 1.0:0.8-1.2.

7. A composite carrier comprising the Sm metal organic framework of any one of claims 1 to 3 and γ -Al ₂ O ₃ Wherein the Sm metal organic framework and gamma-Al ₂ O ₃ The weight ratio of (2) to (15) is 1:2.

8. The composite support of claim 7, wherein the Sm metal organic framework and γ -Al ₂ O ₃ The weight ratio of (2) is 1:4-12.

9. The composite support of claim 7, wherein the Sm metal organic framework and γ -Al ₂ O ₃ The weight ratio of (2) is 1:9.

10. A catalyst comprising the composite support of any one of claims 7 to 9 and an active metal selected from the group consisting of platinum, pd, ni, mo, co, or a combination thereof,

wherein the loading of the active metal is 0.1 to 0.8% by weight.

11. The catalyst of claim 10 wherein the loading of active metal is from 0.2 to 0.4% by weight.

12. The method for preparing a catalyst according to any one of claims 10 to 11, characterized in that the method comprises the steps of:

(1) The Sm metal organic frame and gamma-Al ₂ O ₃ Mixing according to the weight ratio of 1:2-15, adding solvent to form viscous fluid, extruding the viscous fluid to form, drying,

(2) Roasting the formed solid obtained in the step (1) at 400-480 ℃ for 3-6 hours to obtain a composite carrier,

(3) And loading active metal on the composite carrier by an impregnation method to obtain the catalyst.

13. Use of the catalyst according to any one of claims 10 to 11 for preparing a lubricant base oil from coal tar tail oil.

14. The use according to claim 13, wherein the method for preparing lubricating base oil from coal tar tail oil using the catalyst comprises the steps of:

(1) And (3) at 280-350 ℃, utilizing the catalyst to carry out isomerization dewaxing on the coal tar tail oil after catalytic hydrogenation.