CN115850717A

CN115850717A - Sm-MOF, sm-MOF containing catalysts and their use in making base oils from coal tar tail oil

Info

Publication number: CN115850717A
Application number: CN202211553532.9A
Authority: CN
Inventors: 周玉生; 葛庆; 张军; 张钢强; 廖俊; 陈步宁; 郑维军; 程仁杰; 马春梅; 孙朋涛; 田航程; 陈锡武
Original assignee: Xinjiang Xuanli Environmental Protection Energy Co ltd
Current assignee: Xinjiang Xuanli Environmental Protection Energy Co ltd
Priority date: 2022-11-28
Filing date: 2022-11-28
Publication date: 2023-03-28
Anticipated expiration: 2042-11-28
Also published as: CN115850717B

Abstract

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

Description

Sm-MOF, sm-MOF containing catalysts and their use in making base oils from coal tar tail oil

Technical Field

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

Background

As is well known, base oil is a main component of lubricating oil, and base oil (i.e., lubricating oil base oil) in China can be roughly classified into 5 types, and base oil having a high sulfur content and a low viscosity index obtained by extraction is called group I base oil; by chemical reaction of the molecular structure of mineral oils the base oil obtained by the modification is called II base oil; the base oil with higher viscosity index and lower volatility obtained by the combined process is called group III base oil; group IV base oils are a group of synthetic oils of Polyalphaolefins (PAO) which contain no sulfur, phosphorus, metals and waxes and have poor boundary lubricity, and are synthesized from synthetic hydrocarbons, fats, silicone oils, and vegetable oils, reclaimed oils. Certain specific group III base oils are comparable to group IV base oils.

With the continuous development of science and technology, the demand and quality of essential base oil in the industries of automobiles, machinery, metallurgy, electric power, ships, aerospace and the like are continuously improved. According to statistics that the consumption of lubricating oil in China is about 1200 million tons accounting for 15 percent of the total amount of the world in 2020, the continuous improvement of the lubricating oil requirement promotes the vigorous development of the base oil industry. Base oils are obtained by specific catalysts and processes, the choice of which directly affects the base oil quality and yield. Therefore, catalyst research and process exploration in base oil production are one of the current research hotspots.

For example, patent publication No. CN1448480A describes that an isodewaxing catalyst with high selectivity and high stability is prepared by using an SAPO-11 molecular sieve and alumina as main carriers, and a group VIII element as an active metal component, and pretreating the catalyst carrier with an organic amine to improve the coverage of the active metal component on an acid center. Patent publication No. CN105214717A discloses an isodewaxing catalyst obtained by using alkaline earth metal isomorphously modified molecular sieve with TON or MTT topological structure and active alumina as carrier, ammonium salt as modifying substance, noble metal in VIII family metal as active metal, and performing modification and impregnation by ion exchange. Patent publication Nos. CN106554817A and CN106554820A both use ZSM type cracking molecular sieve and silica-alumina as carriers, and use Ni, co, mo and W as active metal elements, and through certain modification, the low pour point base oil is synthesized. Patent publication No. CN108102698A discloses a novel catalyst for producing low-pour-point lubricating oil base oil by synthesizing a rare earth element doped and modified TON type molecular sieve and an inorganic refractory oxide as carriers and precious metals as active components. Patent publication No. CN114471680A discloses a preparation method of a lubricating oil base oil catalyst, which is obtained by compounding a molecular sieve with a ten-membered ring structure and an amorphous inorganic porous material to serve as a carrier, and taking VII group metals and/or VIII group metals (Pt, pd, ru, ir and Re) as active metals under the environment of pH value of 6-8. Patent publication No. CN 104803899A discloses a complex generated by reacting iron, cobalt or nickel with a specific organic substance, which is used as a catalyst for directly synthesizing lubricating oil base oil from ethylene. Patent publication No. CN1803998A discloses a dewaxing catalyst containing a composite molecular sieve, which is a molecular sieve having a macroporous structure and containing non-framework silicon. Patent publication No. CN110841724A discloses a method for manufacturing high-quality lubricant base oil by using a combined catalyst, wherein the combined 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 VIII group metal are used as active metal components. Patent publication No. CN113677778A discloses a method for producing a lubricant base oil, wherein the catalyst is a catalyst in which 1 or more metals selected from the group consisting of elements of group 6, group 8, group 9 and group 10 of the periodic table of elements 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 No. CN112126465A discloses a hydrogenation catalyst composition and a method for preparing lube base oil from Fischer-Tropsch synthesis wax, the method comprises three catalysts which are respectively a hydrogenation pretreatment catalyst, a combined catalyst and a hydrofining catalyst, wherein the hydrogenation pretreatment catalyst takes inorganic oxide as a carrier, cobalt, nickel, molybdenum and tungsten as active metals, and nitrogen, silicon, sulfur and boron as auxiliaries; 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 an MEL structure as a carrier and loads active noble metals (platinum, palladium and iridium), and the catalyst B takes a molecular sieve with an MTW structure as a carrier and loads active noble metals (platinum, palladium and iridium); the hydrorefining catalyst uses heat-resistant inorganic oxide as carrier, metal elements such as platinum, palladium and iridium as active metal, and cobalt, nickel, molybdenum and tungsten as hybridization assistant. Patent publication No. CN113072973A discloses a method for producing lubricant base oil, which comprises five steps, respectively: 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 as active metals; the isomerization dewaxing catalyst is a noble metal-loaded aluminum phosphate molecular sieve catalyst; the supplementary refined catalyst adopts alumina or silica as a carrier, and one or more noble metals of platinum, palladium and iridium are loaded; patent publication No. CN102333592B discloses a hydroisomerization catalyst and a method for producing the catalyst, and also discloses a method for dewaxing a hydrocarbon oil and a method for producing a lubricant base oil. The hydroisomerization catalyst is formed by using ion-exchange zeolite and inorganic oxide as carrier 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, calculated as oxides, is 0.03-2: 1, preferably 0.08-1.5: 1. Patent publication nos. CN1488733A, CN1448480A, CN1289643A, CN1228357A, CN1803998A, CN1382526A and CN101191082A disclose an isomerization pour point depressing catalyst having excellent wax hydroisomerization reaction performance. As can be seen, various catalysts for isodewaxing to produce lube base oil have been studied and developed, but most of these studies have focused on the isodewaxing of petroleum-based hydrocracked tail oil or on the Fischer-Tropsch process. At present, no literature reports a process for producing lubricating oil base oil by using coal tar hydrocracking tail oil as a raw material to perform isodewaxing. The problems of the prior process for producing the lubricating oil base oil by using the coal tar hydrocracking tail oil as the raw material are as follows: the coal tar hydrogenation tail oil has complex components, so that the catalyst used in the process has short service life, few active sites, great influence of pH value during reaction, lack of 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, and have been increasingly used in photocatalysis and electrocatalysis due to their large specific surface area, diverse structural topologies, and abundant active centers. In particular, the metal-organic framework can be used as a carrier of a catalyst (e.g., an active metal) or can be mixed with other carriers to be used as a carrier of the catalyst, and has the function of improving the properties of the catalyst or increasing the catalytic effect of the catalyst.

Disclosure of Invention

An object of one aspect of the present invention is to provide a Sm metal organic framework (Sm-MOF) that 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 framework is monoclinic and has a space group of P2 ₁ /n，

α＝γ＝90°，β＝93.772(9)。

Cell volume of the above Sm Metal organic framework

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

The thermogravimetric analysis curve of the Sm metal organic framework comprises a first-stage weight loss of 40-220 ℃ and a second-stage weight loss of 480-700 ℃.

In another aspect, the present invention provides a method for preparing the Sm metal organic framework, comprising the steps of: 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 pH = 6.

In a preferred embodiment of the invention, the hydrothermal synthesis comprises heating the reaction solution in stages, and then cooling in stages, wherein the temperature in stages is increased from room temperature to 100-130 ℃ after 5-7 hours, the reaction solution is heated to 150-170 ℃ after 10-14 hours of constant temperature and 2-4 hours of constant temperature, and the constant temperature is 65-80 hours. The temperature reduction process of the stepped section is that the reaction liquid is cooled from 160-170 ℃ to room temperature at the speed of 2-4 ℃/h.

In a preferred embodiment of the present invention, 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 to 1.2.

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

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

In another aspect, the present invention provides a method for preparing the above catalyst, comprising the steps of:

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

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

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

In still another aspect, the present invention provides a catalyst comprising the above composite carrier and an active metal selected from platinum, pd, ni, mo, co or a combination thereof, wherein the loading amount of the active metal is 0.1 to 0.8% by weight.

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

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

(2) Roasting the formed solid obtained in the step (1) at 400-480 ℃ for 3-6 h to obtain a 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.

The invention also provides the application of the catalyst in preparing the lubricating oil base oil by using the coal tar tail oil as the raw material.

In some embodiments of the present invention, the method for preparing the lubricant base oil by using the catalyst and taking the coal tar tail oil as the raw material comprises the following steps:

(1) And (3) carrying out isodewaxing on the coal tar tail oil subjected to catalytic hydrogenation by using the catalyst at the temperature of 280-350 ℃.

The invention utilizes Sm metal organic framework and gamma-Al ₂ O ₃ The catalyst is a carrier and is formed by loading active metals, so that the coal tar tail oil after catalytic hydrogenation can be subjected to high-efficiency isodewaxing to generate the base oil of the lubricating oil, and the utilization of coal tar in China is improved.

1kg of the catalyst can be used for cumulatively catalyzing 4 t-5 t of coal tar tail oil to perform isodewaxing.

Drawings

FIG. 1 is a diagram showing the coordination environment of Sm-MOF of the present invention, from which it can be seen that each asymmetric unit comprises an independently crystallized Sm ³⁺ One of Na ⁺ One BDT ligand, three coordinated water molecules, and Sm ³⁺ Coordinates with four ligands, two water molecules. The structure is simple as follows: six carboxyl oxygens and Sml exist in a chelated form, meanwhile, O5, O7 and O2 are used as bridging, the O5 and the O7 are used as bridging oxygens to form Na1 into a heteronuclear bimetallic unit, and Na is connected ⁺ The ion forms a penta-coordinate configuration with 1 oxygen (O5) in a water molecule and 4 atoms in a BDT 4-ligand, of which 3 BDTs ^4- The N atoms of the vehicle-mounted oxygens O2, O7, O11 and 1 BDT 4-in the ligand are all in bridging coordination. The carboxyl group of O2 is used as a bridging carboxyl group to connect heteronuclear bimetallic units into a one-dimensional chain.

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

FIG. 2 is a thermogravimetric analysis graph of Sm-MOF, from which it can be seen that the thermogravimetric analysis curve 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 vs (COO-) appears at 1413cm-1 and carbonyl asymmetry vs (COO-) stretches at 1560cm ^-1 And 1627cm ^-1 Where it appears.

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

FIG. 5 is a graph utilizing different weight ratios of Sm-MOF and gamma-Al ₂ O ₃ And (3) a viscosity index and pour point curve diagram of lubricating oil base oil formed by catalyzing pre-hydrogenated coal tar tail oil by using a catalyst formed by loading platinum on a carrier.

FIG. 6 is a diagram showing the coordination environment of Sm-MOF without Na, which has the chemical formula [ Sm (BDT) (H), prepared in example 7 of the present invention 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 the carrier is loaded with active metal by an impregnation method, the catalyst capable of catalyzing coal tar tail oil to form lubricating oil base oil is formed. The catalyst has multiple active sites and is selectedGood in performance and wide in reaction temperature. The present invention has been completed based on this finding.

Synthesis and characterization of Sm-MOF

The Sm-MOF is a Sm metal coordination polymer having the chemical 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, H ₄ The BDT structure is shown below:

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

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

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

Composite carrierBody and synthesis thereof

The composite support of the present invention comprises the metal organic framework of claim Sm and gamma-Al ₂ O ₃ Wherein said Sm metal organic framework and gamma-Al ₂ O ₃ The weight ratio of (A) to (B) is 1: 2 to 15, more preferably 1:4 to 12. For example, sm metalorganic 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 present invention can be prepared by the following steps:

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

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

In order to ensure the stability of Sm-MOF, the roasting temperature is not higher than 480 ℃.

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

In one embodiment of the present invention, sm metal coordination polymer and gamma-Al are present ₂ O ₃ Is formed into a trilobal shaped body by extrusion molding, dried, and then fired at 430 ℃ in the presence of air, to obtain a carrier which is fired by being subjected to a thermal history of heating at 350 ℃ or more.

Catalyst and synthesis thereof

The catalyst of the present invention comprises the above-described 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 invention is formed by supporting a group VIII metal (e.g., platinum) on the above composite carrier by a conventional impregnation method.

Isodewaxing of coal tar tail oil

The principle of using the catalyst of the invention to carry out isodewaxing on coal tar tail oil to prepare the lubricant base oil is as follows: the catalyst is composed of a carrier with a special pore channel structure and a supported noble metal, and follows the catalysis mechanism of a metal site acid center. The metal sites are Pt metal and the acid centers are Sm-MOF containing supports. The alkane molecules are dehydrogenated at the metal sites to give alkenes which are further protonated at the acid sites to form carbonium ions which undergo rearrangement isomerisation or cracking reactions followed by deprotonation of the carbonium ions to give alkenes. The olefin molecules are hydrogenated at the metal sites to give isoparaffins. During the reaction, the metal site and the acid center play important roles, respectively, the dehydrogenation and hydrogenation processes of normal paraffin are carried out on the metal site, and the isomerization and cracking processes of carbonium ions are carried out on the acid center. The isodewaxing catalyst has the best reactivity when the acidic function of the acid center is balanced with the dehydrogenation/hydrogenation activity of the metal site.

Impregnation method

The method for loading active metal on the composite carrier by the impregnation method is a common method in the field ([ 1 ]]Zhang Jiu light, catalyst preparation process technology [ M ]]China petrochemical press, 2019: 11, 11; [2]Impregnation method for preparing Pt/Al from Zhang Jia Yu, pangli of Wangjia nationality ₂ O ₃ Study of the catalyst-Effect of competing adsorbents on Pt distribution [ J]Journal of chemical industry, 1982 (02): 151-159. ). In one embodiment of the present invention, the specific process of loading the active metal on the composite carrier is as follows: soaking the prepared carrier in solution containing 0.04-0.06 mol/LH ₂ PtCl ₆ And 0.3-0.5 mol/L citric acid aqueous solution, filtering to remove the excess solution after adsorption balance, drying and activating to obtain the catalyst finished product. The loading of Pt is controlled by the concentration and volume of the impregnation solution.

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

In the description of the invention, "coal tar tail oil" is also referred to as "coal tar hydrogenation tail oil" or "coal tar hydrocracking tail oil".

The invention will be further illustrated with reference to the following specific examples. The specific embodiment is implemented on the premise of the technical scheme of the invention, and a detailed implementation mode and an operation process are given. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental methods in the following examples, which are not specified under specific conditions, are generally carried out under conventional conditions. Unless otherwise indicated, ratios and percentages are by weight.

The following examples synthesize Sm-MOF by hydrothermal synthesis using an electrically heated constant temperature forced air drying oven (DHG-9145 AF) manufactured by Shanghai and Shimadik corporation. The required agents were weighed using an analytical balance (Secura 125-1 CN) from Sadoris, germany.

Example 1

1.1 Synthesis of Sm-MOF

Samarium chloride (SmCl) ₃ ) 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole was dissolved in isopropanol and pH =6 acetic acid/sodium acetate buffer (the acetic acid/sodium acetate buffer was prepared by: 54.6g of anhydrous sodium acetate is added into 20ml of 1mol/L acetic acid solution for dissolution, and then the mixture is diluted to 500 ml) by adding water, wherein the volume ratio of isopropanol to a buffer reagent is 1: 5.5, and the details of the used reagent 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 ℃ in a stepped heating mode, keeping the temperature for 72h, and then cooling to room temperature by using a cooling program at the speed of 2-4 ℃/h. The temperature rising mode of the gradient section is that the solution is heated from 30 ℃ to 120 ℃ after 6 hours, the temperature is raised to 160 ℃ after 2 hours after the constant temperature is kept for 12 hours, and H is used after the crystal is filtered ₂ And washing, purifying and drying O and ethanol to obtain light yellow rod-shaped crystals.

TABLE 1 major reagents for the synthesis of Sm-MOF

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Single crystal particles with regular appearance and high crystallinity are selected by an optical microscope (SZ 680, chongqing Ott optical instruments, ltd.). At 296K, the colorless bulk crystals were irradiated by Mo-Ka radiation of Bruker D8 Venture ((R))

) Testing, single crystal diffraction data of the crystal were obtained, and absorption correction was performed on the collected data using the SCALE3 abspeck program. Using SHELXL-97 package and full matrix through F ² The above least squares method optimizes the data. Simultaneously using SQUEEZE program to make solvents DMF and H in the formed crystal mesopores ₂ And (5) processing the O molecules. All the above calculations were performed in the SHELXTL system.

The characterization result shows that the Sm-MOF is a three-dimensional structure, and an asymmetric unit comprises an independent crystal Sm ³⁺ One of Na ⁺ One BDT ligand, three coordinated water molecules, sm ³⁺ Coordinates with four ligands, two water molecules, see (a) in fig. 1. From this figure it can be seen that the six carboxyl oxygens chelate to Sml, where O5, O7, O1 are used as bridging and O5, O7 are used as bridging oxygens linking Na1 to form heteronuclear bimetallic units. The carboxyl where O1 is positioned is taken 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 junctions form a two-dimensional bilayer plane, see fig. 1 (b), and further expand into a three-dimensional structure, see fig. 1 (c). The Sm-O bond length range in the Sm-MOF is as follows:

the Na-O bond length ranges are: />

While the Na-N bond length ranges: />

The bond angle range of O-Sm-O is as follows: 51.3 (2) ° -159.9 (3) °, and the bond angle range of O-Na-O is: 76.11 (13) ° -162.5 (4) ° and the bond angle range of O-Na-N is: 89.41 (19) ° -107.9 (3) ° the Sm (Na) -MOF of the heteronuclear bimetallic complex has Sm-O bond lengths and O-Sm-O bond angles comparable to those of the prior art references (Liu, xinfang; zhang, xiaoyu; li, rongfang; du, liyong; feng, xun; ding, yuqiong. A high sensitivity sensitive and selective "tum off-on" fluorine sensor base on Sm-MOF for the detection of tertiary butyl hydroquinoline [ J ] (Na) -MOF]Dyes and Pigments,2020,178, 108347) were reported to be in agreement. The crystallographic data for Sm-MOF of the invention are set forth in tables 2-1, 2-2 and 2-3. (Table 2-1 lists the crystallographic data of the complex, table 2-2 lists the bond lengths of Sm-MOF; table 2-3 lists the bond angles of Sm-MOF). The infrared spectrum of Sm-MOF is shown in figure 3, from which it can be seen that the characteristic absorption peak of carbonyl symmetry vs (COO-) appears at 1413cm-1, and the carbonyl asymmetry vs (COO-) expansion appears at 1560cm-1 and 1627 cm-1. The thermogravimetric analysis curve of the MOF material comprises a first-stage weight loss at 40-220 ℃ and a second-stage weight loss at 480-700 ℃, wherein the first-stage weight loss mainly comprises free water and crystal water of the lost material, and the second-stage weight loss mainly comprises structure collapse.

TABLE 2-1 crystallographic data for the Complex

Tables 2-2 bond lengths of Sm-MOF

Tables 2-3 bond angles of 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

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 of the composite carrier 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) Mixing Sm-MOF with inorganic oxide gamma-Al ₂ O ₃ Mixing according to the proportion of 1:4, adding a proper amount of water, stirring to form viscous fluid, extruding and molding the viscous fluid, and drying to form a trilobal molded body;

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

(3) The prepared composite carrier is soaked in a solution containing 0.0554mol/LH ₂ PtCl ₆ And 0.4mol/L citric acid aqueous solution, filtering the excess solution after adsorption equilibrium, drying and activating to obtain a catalyst finished product XL-1, wherein the load is controlled by the concentration and volume of the impregnation liquid.

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

The synthesized catalyst XL-1 is charged into an isodewaxing reactor (R2); 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 the pre-hydrogenation reactor (R1) from the top thereof and is subjected to aromatic saturation hydrogenation, the reactor is provided with three bed layers, cold hydrogen is arranged between each two sections for temperature regulation, wherein the reaction airspeed is 0.48, and the hydrogen-oil ratio is 200-300. The prehydrogenation product is discharged from the bottom of the prehydrogenation reactor (R1), the temperature is 150-220 ℃, the prehydrogenation product firstly enters an isomeric feeding and discharging heat exchanger (E1) to exchange heat with an isomeric dewaxing product to 252-325 ℃, then enters an isomeric feeding furnace (F1) to be heated to 280-350 ℃, and finally enters an isomeric dewaxing reactor (R2) to carry out an isomeric cracking reaction, the reactor is provided with three beds, cold hydrogen is arranged between two sections to adjust the temperature, wherein the reaction space velocity is 1. The isomerization dewaxing product enters a supplementary refining reactor for refining reaction after being subjected to heat exchange with feed through E1 and cooled to 202-271 ℃. The base oil qualities produced are 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 this example was used for the cumulative 4t of coal tar tail oil catalytic isomerization dewaxing.

Table 3 base oil quality produced

Examples 2 to 4

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

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

Table 4 base oil quality produced by example 2

Table 5 base oil quality produced in example 3

Table 6 base oil quality produced by example 4

Example 5

5.1 catalyst XL-5

The carrier is inorganic oxide gamma-Al ₂ O ₃ The required catalyst is obtained by loading platinum element in the VIII group metal through a conventional impregnation method, and 0.3 percent of noble metal is loaded in the catalyst.

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

(1) Mixing inorganic oxide gamma-Al ₂ O ₃ Adding a proper amount of water, stirring to form viscous fluid, forming the viscous fluid through extrusion molding, and drying to form a trilobal molded body;

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

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

5.2 preparation of a lube base oil using catalyst XL-5 to catalyze coal tar tail oil according to the conditions and procedure of 1.3 of example 1, the base oil quality produced is shown in Table 7 below.

Table 7 base oil quality produced in example 5

Example 6

6.1 Sm-MOF Synthesis

Samarium chloride (SmCl) ₃ ) Dissolving 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole in isopropanol and acetic acid/sodium acetate buffer reagent with pH =6 (preparation method general example 1) according to the proportion of 1: 1, wherein the volume ratio of the isopropanol to the buffer reagent is 1: 6, stirring the obtained solution at room temperature for 14min, adding the solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining, gradually heating to 170 ℃ by using a stepped heating mode, keeping the temperature for 70H, and then cooling to room temperature by using a cooling program at the speed of 2-4 ℃/H. Wherein the temperature rise mode of the gradient section is that the reaction solution is heated from 30 ℃ to 130 ℃ after 5.5 hours, the temperature is kept for 12 hours, then the temperature is raised to 170 ℃ after 2.5 hours, and H is used after the crystal is filtered ₂ And washing, purifying and drying O and ethanol to obtain light yellow rod-shaped crystals (the determined structure is the same as that of the Sm-MOF synthesized in example 1).

6.2 catalyst XL-6

Sm-MOF ({ [ SmNa (BDT) (H) ₂ O) ₃ ]·2H ₂ O } n) and an inorganic oxide of gamma-Al ₂ O ₃ The catalyst is a composite carrier, the ratio of the composite carrier is 1: 9, and the required catalyst is obtained by loading platinum element in VIII group metal through a conventional impregnation method, and 0.5 percent of noble metal is loaded in the catalyst.

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

(1) Mixing Sm-MOF 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 viscous fluid, extruding and molding the viscous fluid, and drying to form a trilobal molded body;

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

(3) Mixing gamma-Al ₂ O ₃ The carrier is soaked in H solution containing 0.06mol/L ₂ PtCl ₆ And 0.5mol/L citric acid, filtering off the excessive solution after adsorption equilibrium, drying, and activating to obtain the catalystFinished product XL-6.

2.3 preparation of lube base stock from coal tar tail oil by catalysis

The process can be used for carrying out isomerization dewaxing on 5t of coal tar tail oil by cumulatively catalyzing the same 1.3,1kg of catalyst XL-6 in example 1, and the catalytic amount is increased in unit time. The base oil quality produced is shown in table 8 below.

Table 8 base oil quality produced in example 6

Example 7

7.1 samarium chloride (SmCl) ₃ ) Dissolving 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole in isopropanol and a buffer reagent (acetic acid/sodium acetate) with pH =6 according to a ratio of 1: 1, wherein the volume ratio of the isopropanol to the buffer reagent is 1:4, stirring the obtained solution at room temperature for 11min, 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 74H, and then cooling to room temperature by using a cooling program at a speed of 2-4 ℃/H. Wherein the temperature rise mode of the gradient section is that the reaction solution is heated from 30 ℃ to 130 ℃ after 5.5 hours, the temperature is raised to 170 ℃ after 2.5 hours after the constant temperature is kept for 12 hours, and H is used after the crystal is filtered ₂ Washing with O and ethanol, purifying, and drying to obtain yellowish flaky crystal (the coordination environment is shown in FIG. 6). The metal elements in the Sm-MOF only comprise Sm elements, do not comprise Na, and have the chemical formula of [ Sm (BDT) (H) ₂ O) ₃ ]·2H ₂ O。

7.2 catalyst Synthesis

To form Sm-MOF ([ Sm (BDT) (H)) containing Na ₂ O) ₃ ].2H ₂ O) and an inorganic oxide gamma-Al ₂ O ₃ The composite carrier was prepared by supporting platinum of group VIII metals in a ratio of 1: 9 by the impregnation method of example 1 to obtain a desired catalyst in which 0.3% of a noble metal was supported.

The synthesis steps of the catalyst are as follows:

(1) Mixing Sm-MOF containing Na 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 viscous fluid, extruding and molding the viscous fluid, and drying to form a trilobal molded body;

(2) Roasting the leaf-shaped formed body for 3 hours at the temperature of 460 ℃ under the condition of air;

(3) Platinum was loaded as in 1.2 of example 1. The synthesized catalyst is designated XL-7.

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

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

Table 9 base oil quality produced in example 7

It can be seen from example 7 that different preparation conditions, especially different amounts of buffering agent, change the amount of reactants in solution, polarity and pH value, resulting in different molecular formulas of Sm coordination polymers, which do not contain Na and cannot form bimetallic units with double-gold heteronuclear structure, although the coordination polymers also form three-dimensional structures, the structure is unstable. Resulting in a decrease in the strength of the synthesized support.

It is well known that long chain monocyclic aromatic compounds have a higher viscosity index than isoparaffins at the same condensation point. Sm-MOF and gamma-Al of the invention ₂ O ₃ The composite carrier not only provides framework support to enhance mechanical strength, but also plays a role in uniformly dispersing active components, and even can be used as an active center for ring opening, cracking, isomerization and the like by extracting acid points such as B acid, L acid and the like. By comparison, it was found (as shown in FIG. 5) that in the production of a lubricant base oil from coal tar tail oil as a raw material, as the Sm-MOF content in the catalyst was reduced, the base oil wasThe viscosity index of the oil is decreasing and when Sm-MOF is absent, the viscosity index is 102. The reason may be that the rare earth Sm-MOF modified gamma-Al is adopted ₂ O ₃ The acid strength of the carrier is greatly improved. The special pore structure of Sm-MOF can not only provide more active sites and slow down the collapse of internal microporous structure, but also increase the isodewaxing activity of the catalyst due to the bifunctional catalyst formed by rare earth elements and noble metals in Sm-MOF.

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

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.

Claims

1. The Sm metal organic framework is an 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.

2. The Sm metal organic framework of claim 1, wherein the Sm metal organic framework is of the monoclinic system and the space group is P2 ₁ /n，

α = γ =90 °, β =93.772 (9). And/or

The Sm metal coordination polymer has a unit cell volume

And/or

The number of molecules in the unit cell of the Sm metal coordination polymer, Z =4.

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

4. The process for making a Sm metal organic framework as claimed in any one of claims 1 to 3, said process comprising the steps of: 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 pH = 6.

5. The method of making a Sm metal organic framework of claim 4,

the hydrothermal synthesis comprises heating the reaction solution in stages, and then cooling in stages, wherein the heating in stages is carried out by heating the reaction solution from room temperature to 100-130 ℃ for 5-7 hours, keeping the temperature for 10-14 hours, then heating to 150-170 ℃ for 2-4 hours, keeping the temperature for 65-80 hours, and the cooling in stages is carried out by cooling the reaction solution from 160-170 ℃ to room temperature at a speed of 2-4 ℃/h, and/or

In the reaction solution, the molar ratio of samarium chloride to 3, 5-bis (3 ',5' -dicarboxyphenyl) -1H-1,2, 4-triazole is 1.0: 0.8-1.2, and/or

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

6. A composite support comprising a Sm metalorganic framework according to any one of claims 1 to 3 and gamma-Al ₂ O ₃ Wherein said Sm metal organic framework and gamma-Al ₂ O ₃ The weight ratio of (A) to (B) is 1: 2 to 15, more preferably 1:4 to 12, most preferably 1: 9.

7. A catalyst comprising the composite support of claim 6 and an active metal selected from platinum, pd, ni, mo, co, or combinations thereof.

Wherein the loading amount of the active metal is 0.1 to 0.8%, more preferably 0.2 to 0.4% by weight.

8. The method for preparing the catalyst according to claim 7, comprising the steps of:

9. Use of the catalyst of claim 7 in the preparation of lubricant base oil from coal tar tail oil as a feedstock.

10. The use of claim 9, wherein the method for preparing the lubricating base oil by using the catalyst and taking coal tar tail oil as a raw material comprises the following steps: