Catalyst for producing mesitylene from C9 aromatic hydrocarbon and preparation method thereof

Abstract

The invention relates to the technical field of mesitylene production, in particular to a catalyst for producing mesitylene from C9 aromatic hydrocarbon and a preparation method of the catalyst. A silicon-aluminum molecular sieve is subjected to ammonium exchange treatment, and the molecular sieve is filtered and dried; grinding the dried molecular sieve, uniformly mixing the ground molecular sieve with a required amount of binder, adding a required amount of acid, mixing, kneading, carrying out extrusion molding, and drying to obtain a catalyst precursor; roasting the catalyst precursor; impregnating the roasted catalyst precursor with a salt solution of a non-noble metal element, and drying after impregnation to obtain a catalyst intermediate; and roasting the catalyst intermediate to obtain the catalyst for producing mesitylene from C9 aromatic hydrocarbon. The molecular sieve is modified by loading the non-noble metal element, so that the production cost of the catalyst can be reduced, the mesitylene selectivity, the mesitylene yield, the methyl-ethylbenzene conversion rate and the trimethylbenzene yield are improved, and the comprehensive performance of the catalyst and the utilization value of C9 aromatic hydrocarbon are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of trimethylbenzene production, and relates to a catalyst for producing trimethylbenzene from carbon nine aromatics and a preparation method thereof. Background Art

[0002] C9 (carbon nine) aromatics in refining enterprises are mainly from reformed gasoline or pyrolysis gasoline (after hydroprocessing), of which C9 aromatics from reforming units account for about 15% to 20% of their unit capacity. Among C9 aromatics from reforming units, the content of partial trimethylol is 30% to 50%, the content of mesitylene is 5% to 12%, and it contains almost no olefins, with good stability, which is conducive to further processing and separation of high value-added components. Due to the difficulty of separating mesitylene from C9 aromatics, the price has remained high for a long time.

[0003] Mesitylene is a valuable fine chemical raw material. Its main uses include synthetic dyes (weakly acidic Praline RAW, Reactive Brilliant Blue K-3R and RAN), wheat field herbicides, plasticizers, antioxidants, fungicides, mildew inhibitors, crosslinking agents, photosensitizers, and for the production of sedatives, antidotes and other pharmaceutical products. Nanjing Refinery in China has been researching the industrial production of mesitylene for more than 30 years.

[0004] At present, the methods for preparing mesitylene from C9 aromatics mainly include direct separation method and synthesis-separation and purification method. The direct separation and purification method uses C9 mixed aromatics as raw materials and directly distills and separates the mesitylene contained therein. However, since C9 aromatics contain o-methylethylbenzene, which has a boiling point close to that of mesitylene, the direct separation method not only has high energy consumption, but also the purity of mesitylene is difficult to meet the requirements. The synthesis method is divided into alkylation method and isomerization method: the alkylation method uses C9 aromatics and propylene to undergo multiple alkylation reactions to obtain mesitylene. This method requires multiple reactions and requires the use of alkylating agents. The production process is cumbersome and the subsequent treatment is complicated; the isomerization method is to make the unsemantic trimethylol and trimethylol in C9 mixed aromatics undergo isomerization reaction to produce mesitylene.

[0005] A Chinese patent document with publication number CN111039742A discloses a hydrogen-type EUO structure molecular sieve for isomerizing unsymmetrical trimethylbenzene to produce mesitylene. By loading Group VIII platinum and palladium and Group VIB molybdenum elements, under the conditions of 360°C, pressure 0.5 MPa, hydrogen-to-hydrocarbon ratio 600 v / v, and mass space velocity 3.0 h-1, the unsymmetrical trimethylbenzene conversion rate can be 42.46%, the mesitylene selectivity can reach 57.64%, and the mesitylene content in the product can reach a reaction equilibrium of 24.31%.

[0006] Patent publication number CN1102360A discloses a composite zeolite catalyst loaded with precious metal platinum. The catalyst can be used for isomerization of C8 aromatics to produce p-xylene and isomerization of C9 aromatics to produce mesitylene. When used for isomerization of para-xylene, the catalyst is heated to 430°C, the pressure is 0.8 MPa, and the volume space velocity is 3.1 h -1 Under the condition of hydrogen-to-oil molar ratio of 1.5, the conversion rate of partial trimethylolene can reach 40.45%, and the content of mesitylene in the product is 19.69%. Both of the above patents use precious metals, which are relatively expensive, and there is no example of their application in the preparation of mesitylene from C9 mixed aromatics.

[0007] A Chinese patent document with publication number CN102746091A discloses a method for producing mesitylene by hydrogenation and cracking of heavy aromatics. The method uses C9 mixed aromatics as a raw material and a hydrogen-type binderless ten-membered ring zeolite containing 0.005 to 0.5% platinum or palladium as a catalyst. Among them, the hydrogen-type binderless ZSM-5 catalyst loaded with 0.05% Pt and 0.25% Zn by mass ratio can increase the mass fraction of mesitylene in the raw material from 5.03% to 5.26% at 360°C, pressure 2.8MPa, hydrogen-to-hydrocarbon ratio 500v / v, mass space velocity 2.1h-1 and no circulating feed conditions. After calculation, the mesitylene selectivity of the catalyst is 2.88%, the mesitylene yield is 1.56%, and the total mesitylene yield is 49.11%, all of which are relatively low, especially the total mesitylene yield is less than 50%, the content of non-aromatic hydrocarbons with less than 6 carbon atoms is greater than 10%, and the high-value utilization of C9 aromatics is not high. Since it uses precious metal catalysts, it is expensive, the mesitylene yield is low, and there are many by-products, so the production cost of mesitylene is relatively high.

[0008] Therefore, if C9 aromatics with trimethylol as the main component can be converted into isotrimethylol and separated at a lower cost, the company's profits can be greatly improved. Summary of the invention

[0009] The present invention provides a catalyst for producing mesitylene from nine-carbon aromatics and a preparation method thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of low mesitylene yield, large number of by-products and low utilization value of nine-carbon aromatics in the existing production of nine-carbon aromatics.

[0010] One of the technical solutions of the present invention is achieved by the following measures: A method for preparing a catalyst for producing mesitylene from carbon nine aromatics is carried out according to the following steps: The first step is to perform ammonium exchange treatment on the silica-alumina molecular sieve, filter and dry the molecular sieve; The second step is to grind the dried molecular sieve and mix it evenly with the required amount of binder, add the required amount of acid, knead and extrude into strips, and dry them to obtain a catalyst precursor; The third step is to calcine the catalyst precursor; The fourth step is to impregnate the calcined catalyst precursor with a salt solution of a non-precious metal element, and then dry it after the impregnation to obtain a catalyst intermediate; The fifth step is to calcine the catalyst intermediate to obtain a catalyst for producing mesitylene from nine-carbon aromatics.

[0011] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: In the first step, the silica-alumina molecular sieve is one or more of ZSM type, mordenite type, and β type molecular sieve.

[0012] In the above first step, during the ammonium exchange treatment, the ammonium salt is ammonium chloride or ammonium nitrate, and the exchange conditions are: 50°C to 90°C, ammonium salt concentration is 0.5 mol / L to 2.5 mol / L, liquid-solid ratio is 6:1 to 10:1, exchange time is 2h to 6h, and the number of exchanges is 1 to 3 times.

[0013] In the second step, the mass ratio of the dried molecular sieve to the binder is 10:1 to 1:1, and the binder is one of pseudo-boehmite, alumina, and silica sol.

[0014] In the second step, the acid is one of dilute nitric acid, citric acid and glacial acetic acid, the drying temperature is 100° C. to 150° C., and the drying time is 2 hours to 12 hours.

[0015] In the third step, the calcination temperature is 450° C. to 650° C., the calcination atmosphere is air, and the calcination time is 2 hours to 10 hours.

[0016] In the fourth step, the non-precious metal element is one or more of magnesium, iron, nickel, cobalt, ruthenium, molybdenum, chromium and tungsten, wherein the mass of the non-precious metal element accounts for 0.1% to 10.0% of the mass of the catalytic precursor.

[0017] In the fourth step, the immersion conditions are 25°C to 80°C, the liquid-to-solid ratio is 0.5 to 2.0, the immersion time is 8 hours to 48 hours, the drying temperature is 100°C to 150°C, and the drying time is 2 hours to 12 hours.

[0018] In the fifth step, the calcination temperature is 450° C. to 650° C., the calcination atmosphere is air, and the calcination time is 2 hours to 10 hours.

[0019] The second technical solution of the present invention is achieved through the following measures: a catalyst obtained by a preparation method of a catalyst for producing mesitylene from nine-carbon aromatics.

[0020] The present invention modifies the molecular sieve by loading non-precious metal elements, which can reduce the catalyst production cost, improve the mesitylene selectivity, mesitylene yield, methyl and ethyl benzene conversion rate and trimethylbenzene yield, and significantly improve the comprehensive performance of the catalyst and the utilization value of carbon nine aromatics. DETAILED DESCRIPTION

[0021] The present invention is not limited by the following embodiments, and specific implementation methods can be determined according to the technical scheme of the present invention and actual conditions. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all known and commonly used chemical reagents and chemicals in the prior art.

[0022] The present invention will be further described below in conjunction with embodiments: Example 1: The preparation method of the catalyst for producing mesitylene from carbon nine (C9) aromatics is carried out according to the following steps: The first step is to perform ammonium exchange treatment on the silica-alumina molecular sieve, filter and dry the molecular sieve; The second step is to grind the dried molecular sieve and mix it evenly with the required amount of binder, add the required amount of acid, knead and extrude into strips, and dry them to obtain a catalyst precursor; The third step is to calcine the catalyst precursor; The fourth step is to impregnate the calcined catalyst precursor with a salt solution of a non-precious metal element, and then dry it after the impregnation to obtain a catalyst intermediate; The fifth step is to calcine the catalyst intermediate to obtain a catalyst for producing mesitylene from nine-carbon aromatics.

[0023] The catalyst obtained by the invention does not use precious metals and can be used in the reaction of producing mesitylene from C9 aromatic hydrocarbons to significantly improve the yield of mesitylene, reduce by-products such as BTX, and improve the utilization value of C9 aromatic hydrocarbons.

[0024] When the catalyst obtained by the present invention is used to produce mesitylene from C9 aromatic hydrocarbons, when unsymmetrical trimethylolene is used as the raw material, the liquid product yield is 93% to 99%, and the mesitylene yield is 15% to 25%; when C9 mixed aromatic hydrocarbons are used as the raw material, the mesitylene selectivity is 70% to 80%, the liquid product yield is 93% to 99.5%, the mesitylene yield is 10% to 15%, the trimethylolene yield is 85% to 96%, and the methylethylbenzene conversion rate is 90% to 99%. Liquid chromatography is used to perform full component analysis on the reaction raw materials and products, and the mesitylene selectivity, mesitylene yield, trimethylolene yield, liquid product yield, and o-methylethylbenzene conversion rate are calculated according to the following formulas (1) to (5): Embodiment 2: As an optimization of the above embodiment, in the first step, the silica-alumina molecular sieve is one or more of ZSM type, mordenite type, and β type molecular sieve.

[0025] Example 3: As an optimization of the above example, in the first step, during the ammonium exchange treatment, the ammonium salt is ammonium chloride or ammonium nitrate, and the exchange conditions are: 50°C to 90°C, ammonium salt concentration is 0.5 mol / L to 2.5 mol / L, liquid-solid ratio is 6:1 to 10:1, exchange time is 2h to 6h, and the number of exchanges is 1 to 3 times.

[0026] Example 4: As an optimization of the above example, in the second step, the mass ratio of the dried molecular sieve to the binder is 10:1 to 1:1, and the binder is one of pseudo-boehmite, alumina, and silica sol.

[0027] Example 5: As an optimization of the above example, in the second step, the acid is one of dilute nitric acid, citric acid, and glacial acetic acid, the drying temperature is 100° C. to 150° C., and the drying time is 2 hours to 12 hours.

[0028] Example 6: As an optimization of the above example, in the third step, the calcination temperature is 450°C to 650°C, the calcination atmosphere is air, and the calcination time is 2 hours to 10 hours.

[0029] Example 7: As an optimization of the above example, in the fourth step, the non-precious metal element is one or more of magnesium, iron, nickel, cobalt, ruthenium, molybdenum, chromium, and tungsten, wherein the mass of the non-precious metal element accounts for 0.1% to 10.0% of the mass of the catalytic precursor.

[0030] Example 8: As an optimization of the above example, in the fourth step, the impregnation conditions are 25°C to 80°C, the liquid-to-solid ratio is 0.5 to 2.0, the impregnation time is 8 hours to 48 hours, the drying temperature is 100°C to 150°C, and the drying time is 2 hours to 12 hours.

[0031] Example 9: As an optimization of the above example, in the fifth step, the calcination temperature is 450°C to 650°C, the calcination atmosphere is air, and the calcination time is 2 hours to 10 hours.

[0032] Example 10: A catalyst obtained by a method for preparing a catalyst for producing mesitylene from nine-carbon aromatics.

[0033] Example 11: The preparation method of the catalyst for producing mesitylene from carbon nine (C9) aromatics is carried out according to the following steps: In the first step, 50 g of commercially available mordenite molecular sieve raw powder was exchanged with 400 g of 1 mol / L ammonium chloride solution at 80°C for 3 hours, the filter cake was washed with deionized water until the pH value was neutral, and the washed filter cake was dried at 100°C for 4 hours; In the second step, the molecular sieve after drying is ground and evenly mixed with 12.5g pseudo-boehmite, and 1.25g sesbania powder and 1g citric acid are added at the same time, and appropriate amount of deionized water is added to knead and extrude into strips. The catalyst after extrusion is dried at 100°C for 8 hours to obtain a catalyst precursor; The third step is to place the dried catalyst precursor in a muffle furnace for calcination. The temperature is raised from 20°C for 6 hours to 530°C for 6 hours. After the calcination is completed, the catalyst precursor is taken out after the temperature is naturally cooled and crushed into particles of 1 mm to 3 mm. The fourth step is to prepare a mixed solution of nickel nitrate and ammonium molybdate of the same volume as the catalyst precursor according to 0.5% nickel and 1.0% molybdenum by mass of the catalyst precursor, and place the crushed catalyst precursor in the mixed solution of nickel and molybdenum of the same volume at room temperature for immersion diffusion for 12 hours, then immersion diffusion at 60° C. for 4 hours, and then drying at 110° C. for 6 hours to obtain a catalyst intermediate; The fifth step is to place the dried catalyst precursor in a muffle furnace for calcination. The heating program is: heating from 20°C for 6 hours to 550°C for 4 hours. After the calcination is completed, the temperature is naturally cooled to obtain a catalyst for producing mesitylene from nine-carbon aromatics. The sample is recorded as S1.

[0034] Example 12: The preparation method of the catalyst for producing mesitylene from carbon nine (C9) aromatics is carried out according to the following steps: In the first step, 80 g of commercially available β-zeolite molecular sieve raw powder was exchanged with 800 g of 1 mol / L ammonium chloride solution at 80°C for 3 hours, the filter cake was washed with deionized water until the pH value was neutral, and the washed filter cake was dried at 100°C for 4 hours; The second step is to grind the dried molecular sieve and mix it evenly with pseudo-boehmite at a mass ratio of 4:1, and add 2% of the total mass of the molecular sieve and pseudo-boehmite and 1% of citric acid, add appropriate amount of deionized water, knead and extrude into strips, and dry the extruded catalyst at 100° C. for 8 hours to obtain a catalyst precursor; The third step is to place the dried catalyst precursor in a muffle furnace for calcination. The temperature is raised from 20°C for 6 hours to 530°C for 6 hours. After the calcination is completed, the catalyst precursor is taken out after the temperature is naturally cooled and crushed into particles of 1 mm to 3 mm. The fourth step is to prepare a mixed solution of nickel nitrate and tungsten phosphate with an equal volume of the catalyst precursor according to 0.5% nickel and 0.5% tungsten by mass of the catalyst precursor, and place the crushed catalyst precursor in the equal volume of the nickel-tungsten mixed solution for immersion diffusion at room temperature for 12 hours, then immersion diffusion at 60°C for 4 hours, and then drying at 110°C for 6 hours to obtain a catalyst intermediate; The fifth step is to place the dried catalyst precursor in a muffle furnace for calcination. The heating program is: heating from 20°C for 6 hours to 550°C for 4 hours. After the calcination is completed, the temperature is naturally cooled to obtain a catalyst for producing mesitylene from nine-carbon aromatics. The sample is recorded as S2.

[0035] Example 13: The preparation method of the catalyst for producing mesitylene from carbon nine (C9) aromatics is carried out according to the following steps: In the first step, 80 g of commercially available mordenite molecular sieve raw powder was exchanged with 800 g of 1 mol / L ammonium chloride solution at 80°C for 3 hours, the filter cake was washed with deionized water until the pH value was neutral, and the washed filter cake was dried at 100°C for 4 hours; The second step is to grind the dried molecular sieve and mix it evenly with pseudo-boehmite at a mass ratio of 4:1, and add 2% of the total mass of the molecular sieve and pseudo-boehmite, add appropriate amount of deionized water, knead and extrude into strips, and dry the extruded catalyst at 100° C. for 8 hours to obtain a catalyst precursor; The third step is to place the dried catalyst precursor in a muffle furnace for calcination. The temperature is raised from 20°C for 6 hours to 530°C for 6 hours. After the calcination is completed, the catalyst precursor is taken out after the temperature is naturally cooled and crushed into particles of 1 mm to 3 mm. The fourth step is to prepare a mixed solution of magnesium nitrate and ammonium molybdate of the same volume as the catalyst precursor according to 0.5% magnesium and 2.5% molybdenum by mass of the catalyst precursor, and place the crushed catalyst precursor in the mixed solution of magnesium and molybdenum of the same volume at room temperature for immersion diffusion for 12 hours, then immersion diffusion at 60° C. for 4 hours, and then drying at 110° C. for 6 hours to obtain a catalyst intermediate; The fifth step is to place the dried catalyst precursor in a muffle furnace for calcination. The heating program is: heating from 20°C for 6 hours to 550°C for 4 hours. After the calcination is completed, the temperature is naturally cooled to obtain a catalyst for producing mesitylene from nine-carbon aromatics. The sample is recorded as S3.

[0036] Example 14: The preparation method of the catalyst for producing mesitylene from carbon nine (C9) aromatics is carried out according to the following steps: The first step is to take 70g of commercially available mordenite molecular sieve raw powder, exchange it with 700g of 1mol / L ammonium chloride solution at 80°C for 3 hours, wash the filter cake with deionized water until the pH value is neutral and repeat the exchange once, and dry the washed filter cake at 120°C for 3 hours; The second step is to place the dried molecular sieve in a muffle furnace for calcination, and the temperature program is: 20°C for 6 hours and then heated to 550°C for 6 hours. The calcined molecular sieve is ground and mixed with pseudo-boehmite at a mass ratio of 4:1. At the same time, 3% of the total mass of the molecular sieve and pseudo-boehmite and 4% of dilute nitric acid are added to knead and extrude into strips. The extruded catalyst is dried at 120°C for 4 hours to obtain a catalyst precursor. The third step is to crush the catalyst precursor into particles of 1 mm to 3 mm; The fourth step is to prepare a mixed solution of iron nitrate and tungsten phosphate with an equal volume of the catalyst precursor according to 0.5% iron and 1.25% tungsten by mass of the catalyst precursor, and place the crushed catalyst precursor in the mixed solution of iron and tungsten with an equal volume at room temperature for immersion and diffusion for 24 hours, and then dry it at 120° C. for 2 hours to obtain a catalyst intermediate; The fifth step is to place the dried catalyst precursor in a muffle furnace for calcination. The heating program is: heating from 20°C for 6 hours to 550°C for 4 hours. After the calcination is completed, the temperature is naturally cooled to obtain a catalyst for producing mesitylene from nine-carbon aromatics. The sample is recorded as S4.

[0037] Example 15: The preparation method of the catalyst for producing mesitylene from carbon nine (C9) aromatics is carried out according to the following steps: In the first step, 80 g of commercially available ZSM-5 molecular sieve raw powder was exchanged with 800 g of 1 mol / L ammonium chloride solution at 80 ° C for 3 hours, the filter cake was washed with deionized water until the pH value was neutral, the washed filter cake was dried at 120 ° C for 3 hours, and the dried molecular sieve was placed in a muffle furnace for calcination. The heating program was: 20 ° C for 6 hours and then heated to 540 ° C for 6 hours. In the second step, the calcined molecular sieve is ground and evenly mixed with 20g pseudo-boehmite, and 3g sesbania powder and an appropriate amount of 4% dilute nitric acid are added to knead and extrude into strips. The extruded catalyst is dried at 120°C for 3 hours to obtain a catalyst precursor; The third step is to crush the catalyst precursor into particles of 1 mm to 3 mm; The fourth step is to prepare a mixed solution of nickel nitrate and ammonium molybdate of equal volume to the catalyst precursor according to 0.5% nickel and 1.0% molybdenum by mass of the catalyst precursor, and place the crushed catalyst precursor in the mixed solution of equal volume of nickel and molybdenum at room temperature for immersion diffusion for 24 hours, and then dry it at 120° C. for 2 hours to obtain a catalyst intermediate; The fifth step is to place the dried catalyst precursor in a muffle furnace for calcination. The heating program is: heating from 20°C for 6 hours to 550°C for 4 hours. After the calcination is completed, the temperature is naturally cooled to obtain a catalyst for producing mesitylene from nine-carbon aromatics. The sample is recorded as S5.

[0038] Example 16: The preparation method of the catalyst for producing mesitylene from carbon nine (C9) aromatics is carried out according to the following steps: In the first step, 80 g of commercially available ZSM-5 molecular sieve raw powder was exchanged with 700 g of 1 mol / L ammonium chloride solution at 80 ° C for 3 hours, the filter cake was washed with deionized water until the pH value was neutral, the washed filter cake was dried at 120 ° C for 3 hours, and the dried molecular sieve was placed in a muffle furnace for calcination. The heating program was: 20 ° C for 6 hours and then heated to 540 ° C for 6 hours. The second step is to grind the calcined molecular sieve and mix it evenly with pseudo-boehmite at a mass ratio of 4:1, and add 3% of the total mass of the molecular sieve and pseudo-boehmite and an appropriate amount of 4% dilute nitric acid to knead and extrude into strips. The extruded catalyst is dried at 120° C. for 3 hours to obtain a catalyst precursor; The third step is to crush the catalyst precursor into particles of 1 mm to 3 mm; The fourth step is to prepare a mixed solution of cobalt sulfate and ammonium molybdate of the same volume as the catalyst precursor according to 0.5% cobalt and 2.5% molybdenum by mass of the catalyst precursor, and place the crushed catalyst precursor in the mixed solution of cobalt and molybdenum of the same volume at room temperature for immersion and diffusion for 24 hours, and then dry it at 120° C. for 2 hours to obtain a catalyst intermediate; The fifth step is to place the dried catalyst precursor in a muffle furnace for calcination. The heating program is: heating from 20°C for 6 hours to 550°C for 4 hours. After the calcination is completed, the temperature is naturally cooled to obtain a catalyst for producing mesitylene from nine-carbon aromatics. The sample is recorded as S6.

[0039] Example 17: The catalyst for producing mesitylene from carbon nine aromatics prepared in Examples 11 to 16 was used, and mesitylene (purity ≥ 98%) purchased from Fuchen (Tianjin) Chemical Reagent Co., Ltd. was used as raw material. The catalyst prepared in the above steps was first reduced and activated using a fixed bed evaluation device with a catalyst loading of 100 mL, and then the reaction activity and selectivity were evaluated. The reaction temperature was 240°C to 360°C, the reaction pressure was 1.5 MPa, and the mass space velocity of mesitylene was 1.0 h -1 , (taking samples S1 and S5 as examples) the reaction results are shown in Table 1.

[0040] Example 18: The catalyst for producing mesitylene from carbon nine aromatics prepared in Examples 11 to 16 was used, and mesitylene (purity ≥ 98%) purchased from Fuchen (Tianjin) Chemical Reagent Co., Ltd. was used as raw material. The catalyst prepared in the above steps was first reduced and activated using a fixed bed evaluation device with a catalyst loading of 100 mL, and then the reaction activity and selectivity were evaluated. The reaction temperature was 260°C to 360°C, the reaction pressure was 1.5 MPa, and the mass space velocity of mesitylene was 1.0 h -1 Up to 2.0h -1(Except S6 airspeed is 2.0h -1 Except for the above, the other reaction space velocities are all 1.0h -1 ), wherein the composition of the reaction raw material C9 mixed aromatics is shown in Table 2, and the reaction results are shown in Table 3.

[0041] Example 19: The catalyst S5 for producing mesitylene from C9 aromatics prepared in Example 15 was used. The C9 mixed aromatics reformed in the refinery were used as the raw material. The reaction activity and selectivity of the catalyst prepared in the above steps were evaluated using a fixed bed evaluation device with a catalyst loading of 100 mL. The reaction temperature was 340°C, the reaction pressure was 1.5 MPa, and the mass space velocity of C9 mixed aromatics was 1.0 h -1 Up to 4.0h -1 The reaction results are shown in Table 4.

[0042] According to Table 1, Table 3 and Table 4, the catalyst for producing mesitylene from C9 aromatics prepared by the present invention, when used for producing mesitylene from C9 aromatics, when using unisex trimethylolbenzene as raw material, the liquid product yield is 95% to 99.5%, and the mesitylene yield is 9% to 25%; when using C9 mixed aromatics as raw material, the mesitylene selectivity is 50% to 80%, the liquid product yield is 93% to 99.5%, the mesitylene yield is 1.5% to 13%, the trimethylolbenzene yield is 70% to 96%, and the methyl and ethylbenzene conversion rate is 18% to 99% (because the methyl and ethylbenzene content in the unisex trimethylolbenzene raw material is less than 2%, and the methyl and ethylbenzene content in the C9 mixed aromatics raw material is generally above 10%, therefore, when using unisex trimethylolbenzene as raw material, the focus is on the mesitylene yield, the trimethylolbenzene yield and the liquid product yield; when using C9 mixed aromatics as raw material, the focus is on the mesitylene yield, the methyl and ethylbenzene conversion rate and the trimethylolbenzene yield).

[0043] In summary, the present invention modifies the molecular sieve by loading non-precious metal elements, which can reduce the catalyst production cost, improve the mesitylene selectivity, mesitylene yield, methyl and ethyl benzene conversion rate and trimethylbenzene yield, and significantly improve the comprehensive performance of the catalyst and the utilization value of carbon nine aromatics.

[0044] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for preparing a catalyst for producing mesitylene from nine-carbon aromatics. Features Follow the steps below: The first step is to perform ammonium exchange treatment on the silica-alumina molecular sieve, filter and dry the molecular sieve; The second step is to grind the dried molecular sieve and mix it evenly with the required amount of binder, add the required amount of acid, knead and extrude into strips, and dry them to obtain a catalyst precursor; The third step is to calcine the catalyst precursor; The fourth step is to impregnate the calcined catalyst precursor with a salt solution of a non-precious metal element, and then dry it after the impregnation to obtain a catalyst intermediate; The fifth step is to calcine the catalyst intermediate to obtain a catalyst for producing mesitylene from nine-carbon aromatics.

2. The method for preparing the catalyst for producing mesitylene from carbon nine aromatics according to claim 1, Features In the first step, the silica-alumina molecular sieve is one or more of ZSM type, mordenite type, and β type molecular sieve.

3. The method for preparing a catalyst for producing mesitylene from carbon nine aromatics according to claim 1 or 2, Features In the first step, during the ammonium exchange treatment, the ammonium salt is ammonium chloride or ammonium nitrate, and the exchange conditions are: 50°C to 90°C, ammonium salt concentration is 0.5 mol / L to 2.5 mol / L, liquid-solid ratio is 6:1 to 10:1, exchange time is 2h to 6h, and the number of exchanges is 1 to 3 times.

4. The method for preparing a catalyst for producing mesitylene from nine-carbon aromatics according to claim 1, 2 or 3, Features In the second step, the mass ratio of the dried molecular sieve to the binder is 10:1 to 1:1, and the binder is one of pseudo-boehmite, alumina, and silica sol.

5. A method for preparing a catalyst for producing mesitylene from nine-carbon aromatics according to any one of claims 1 to 4, Features In the second step, the acid is one of dilute nitric acid, citric acid, and glacial acetic acid, the drying temperature is 100° C. to 150° C., and the drying time is 2 hours to 12 hours.

6. A method for preparing a catalyst for producing mesitylene from nine-carbon aromatics according to any one of claims 1 to 5, Features In the third step, the calcination temperature is 450° C. to 650° C., the calcination atmosphere is air, and the calcination time is 2 hours to 10 hours.

7. A method for preparing a catalyst for producing mesitylene from nine-carbon aromatics according to any one of claims 1 to 6, Features In the fourth step, the non-precious metal element is one or more of magnesium, iron, nickel, cobalt, ruthenium, molybdenum, chromium, and tungsten, wherein the mass of the non-precious metal element accounts for 0.1% to 10.0% of the mass of the catalytic precursor.

8. A method for preparing a catalyst for producing mesitylene from nine-carbon aromatics according to any one of claims 1 to 7, Features In the fourth step, the impregnation conditions are 25° C. to 80° C., the liquid-to-solid ratio is 0.5 to 2.0, the impregnation time is 8 hours to 48 hours, the drying temperature is 100° C. to 150° C., and the drying time is 2 hours to 12 hours.

9. The method for preparing the catalyst for producing mesitylene from carbon nine aromatics according to any one of claims 1 to 8, Features In the fifth step, the calcination temperature is 450° C. to 650° C., the calcination atmosphere is air, and the calcination time is 2 hours to 10 hours.

10. A catalyst for producing mesitylene from nine-carbon aromatics obtained by the preparation method according to any one of claims 1 to 9.

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