Catalyst for preparing mesitylene and preparation method thereof

Abstract

The invention discloses a catalyst for preparing mesitylene. The catalyst is prepared from the following components: 65%-80% of a molecular sieve, 15%-30% of gamma-Al2O3 and 0.25%-2.5% of a metal element. The preparation method comprises the following steps: uniformly mixing a molecular sieve and a gamma-Al2O3 precursor substance respectively, adding a peptizing agent and an extrusion aid, and kneading to obtain an initial product; carrying out extrusion forming on the initial product, drying and roasting at high temperature to obtain a catalyst body; and carrying out equivalent-volume impregnation on the catalyst body and a metal salt solution for 24-26 hours, taking out and drying, and finally roasting at high temperature to obtain the mesitylene catalyst. The prepared catalyst has acid strength and pore size suitable for isomerization of 1, 2, 4-trimethylbenzene, dealkylation reaction and disproportionation reaction are effectively inhibited, generation of xylene and tetramethylbenzene is reduced, the selectivity of isomerization reaction can reach 67%, the yield of 1, 2, 4-trimethylbenzene can reach 24.5%, and waste of raw materials is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts for preparing mesitylene, and in particular relates to a catalyst for preparing mesitylene and a method for preparing the catalyst. Background Art

[0002] Mesitylene is 1,3,5-trimethylbenzene, with the molecular formula C 9 H 12 , is an organic compound obtained by replacing three hydrogen atoms in the symmetrical position of the benzene ring with a methyl group. It is colorless and has a special smell. It can be separated from coal tar and crude petroleum products. Mesitylene is a high-value fine chemical raw material. It can be used to produce dye intermediates such as reactive brilliant blue and Pra brilliant blue RAW, and to prepare trimesic acid, M acid, mesitylene antioxidant 330, high-efficiency wheat field herbicide, mesitylene polyacetaldehyde resin, epoxy resin, polyester resin stabilizer, alkyd resin plasticizer, etc., and has broad market prospects. According to different technical conditions and raw material sources, mesitylene is currently mainly produced by separation and synthesis. Among them, separation methods include distillation, sulfonation, deep cold crystallization, HF-BF3 extraction, isomerization and alkylation; synthesis methods mainly include acetone and concentrated sulfuric acid synthesis and xylene gas phase synthesis; the current domestic industrial production methods are mainly based on alkylation and mesitylene isomerization. Isomerization catalysts for converting unsimilar trimethylolene into mesitylene have been reported for a long time. The carriers thereof are usually composed of alumina (or silica) and zeolite and loaded with one or more metal components.

[0003] The Chinese invention patent with publication number CN1510017A discloses a method for preparing mesitylene and tetramethylbenzene, wherein the trimethylbenzene is treated with an acid catalyst containing zeolite, and the catalyst used is β zeolite, Y zeolite, ZSM-12 zeolite, MCM-22 zeolite, NU-88 zeolite, needle zeolite or ERS-10 zeolite, and the trimethylbenzene undergoes isomerization reaction and alkyl transfer reaction at the same time to generate mesitylene and tetramethylbenzene, and the conversion rate reaches 50-80%; the Chinese invention patent with publication number CN102746092A discloses a heavy aromatic hydrocarbon A method for producing mesitylene by hydrocracking separation uses a hydrogen-type binderless ten-membered ring zeolite loaded with 0.005-0.5% by mass of platinum or palladium as a catalyst, and uses hydrogen and heavy aromatics as raw materials for hydrocracking treatment, which can increase the production of BTX aromatics and separate and produce mesitylene; Li Zhongming et al. reacted trimethylol with hydrogen on an aluminum-deficient mordenite catalyst impregnated with aluminum and nickel to produce mesitylene, and have achieved industrial production in Nanjing Refinery, but its output does not reach the designed capacity of 200 tons / year, the scale is small, the production cost is high, and the purity is difficult to reach 98.5%.

[0004] Mixed trimethylolene gas phase isomerization uses mixed trimethylolene (from the bottom oil of the distillation separation of mesitylene) instead of pure trimethylolene, and uses nickel-molybdenum mordenite as a catalyst to complete the isomerization reaction, so that mesitylene products with a near thermodynamic equilibrium distribution can be obtained. The reaction conditions obtained by the Nanjing Refinery Research Institute after investigating this method are temperature 320℃-380℃, pressure 0.5MPa-1.5MPa, space velocity 1.0h-1-2.0h-1, and a 400h life test show that the catalyst is almost not deactivated and has good performance.

[0005] The Chinese invention patent with publication number CN111039742A discloses a catalyst for isomerization of trimethylbenzene to mesitylene, which comprises a hydrogen-type EUO structure molecular sieve and a γ-Al 2 O 3 , as well as two metals of Group VIII elements and one metal of Group VIB elements. The catalyst has strong anti-coking ability and the yield of mesitylene in the product reaches 24%.

[0006] However, the above methods all use molecular sieves as catalysts for isomerization reactions. However, the proton acid center of the molecular sieve can not only undergo isomerization reactions, but also disproportionation reactions and dealkylation reactions, resulting in low isomerization selectivity in the reaction process. The above patent documents do not mention the selectivity of the catalyst or the selectivity of the catalyst is low. A higher conversion rate is required to achieve the same single-pass yield, and the amount of by-products is larger, resulting in a waste of the raw material trimethylol and a reduced overall yield. Summary of the invention

[0007] The purpose of the present invention is to provide a catalyst for preparing mesitylene, which solves the problem of large amount of by-products and waste of raw materials.

[0008] Another object of the present invention is to provide a method for preparing the above catalyst.

[0009] The technical solution adopted by the present invention is that the catalyst for preparing mesitylene is composed of the following components in terms of mass percentage: 65% to 80% molecular sieve, γ-Al 2 O 3 15% to 30% of aluminum and 0.25% to 2.5% of metal elements. The sum of the mass percentages of the above components is 100%.

[0010] The present invention is also characterized in that:

[0011] Furthermore, the molecular sieve is composed of MFI molecular sieve and MOR molecular sieve, the mass of MFI molecular sieve accounts for 70% to 100%, the mass of MOR molecular sieve accounts for 0 to 30%, and the SiO contained in MFI molecular sieve and MOR molecular sieve is 20% to 30%. 2 and Al 2 O3 The molar ratio is 10-40:1.

[0012] Furthermore, the metal element is any one or more of Group VIII elements, Group I elements or lanthanide metals, the Group VIII elements are platinum, palladium, iridium, ruthenium, cobalt or nickel, the Group I elements are gold and silver, and the lanthanide metal elements are lanthanum and cerium.

[0013] Furthermore, based on the weight percentage of the catalyst, the loading amount of the Group VIII element is 0.5% to 2.0%, the loading amount of the Group I element is 0 to 0.25%, and the loading amount of the lanthanide metal element is 0 to 0.25%.

[0014] Another technical solution adopted by the present invention is a method for preparing a catalyst for preparing mesitylene, which is specifically implemented according to the following steps:

[0015] S1, take molecular sieve and γ-Al 2 O 3 The precursor materials are mixed evenly, γ-Al 2 O 3 The dry basis weight accounts for 20% to 30%, and then a peptizing agent and an extrusion aid are added for kneading to obtain a primary product;

[0016] S2, extruding the primary product into a shape, drying it at 80°C to 120°C for 4h to 8h to obtain a dried product, and then calcining the dried product at 520°C to 550°C for 4h to 5h to obtain a catalyst body;

[0017] S3. Immerse the catalyst body and the metal salt solution in equal volumes for 24 to 26 hours, take out and dry at 80 to 120°C for 4 to 8 hours, and finally calcine at 520 to 550°C for 4 to 5 hours to obtain a catalyst for preparing mesitylene.

[0018] Another technical solution of the present invention is also characterized in that:

[0019] Furthermore, the molecular sieve is composed of MFI molecular sieve and MOR molecular sieve, the mass of MFI molecular sieve accounts for 70% to 100%, the mass of MOR molecular sieve accounts for 0 to 30%, and the SiO contained in MFI molecular sieve and MOR molecular sieve is 20% to 30%. 2 and Al 2 O 3 The molar ratio is 10 to 40:1

[0020] Furthermore, γ-Al 2 O 3 The precursor material is aluminum sol or pseudo-boehmite.

[0021] Furthermore, in step 1, the peptizing agent is an aqueous solution of any one or more of nitric acid, phosphoric acid, citric acid, oxalic acid and formic acid, and the mass percentage of the aqueous solution of the peptizing agent is 2%-8%, and the mass of the peptizing agent accounts for 2 O 3 25%-50% of the total mass.

[0022] Furthermore, in step 1, the extrusion aid is any one or more of polyol, sesbania powder or graphite, and the mass of the extrusion aid accounts for 2 O 3 2%-15% of total mass.

[0023] Furthermore, in step 3, the metal element is any one or more of Group VIII elements, Group I elements or lanthanide metals, Group VIII elements are platinum, palladium, iridium, ruthenium, cobalt, and nickel, Group I elements are gold and silver, and lanthanide metal elements are lanthanum and cerium. In terms of catalyst weight percentage, the loading amount of platinum, palladium, iridium, ruthenium, cobalt, nickel and other elements is 0.5% to 2.0%, the loading amount of gold and silver elements is 0 to 0.25%, and the loading amount of lanthanum and cerium elements is 0 to 0.25%.

[0024] The beneficial effects of the present invention are:

[0025] (1) The catalyst prepared by the present invention has an acid strength and pore size suitable for the isomerization of mesitylene, effectively inhibits the dealkylation reaction and the disproportionation reaction, reduces the generation of xylene and tetramethylbenzene, and the selectivity of the isomerization reaction can be as high as 67%. The yield of mesitylene can be as high as 24.5%, which is close to the thermodynamic equilibrium composition of the isomerization reaction, reduces the waste of raw materials, and improves the economic benefits.

[0026] (2) The preparation method of the catalyst of the present invention has simple process, easy operation, low cost and is suitable for large-scale industrial production. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with specific implementation modes.

[0028] The catalyst for preparing mesitylene of the present invention is composed of the following components according to mass percentage: 65% to 80% of molecular sieve, γ-Al 2 O 3 15% to 30% of aluminum and 0.25% to 2.5% of metal elements. The sum of the mass percentages of the above components is 100%.

[0029] The molecular sieve is composed of MFI molecular sieve and MOR molecular sieve. The mass of MFI molecular sieve accounts for 70% to 100%, and the mass of MOR molecular sieve accounts for 0 to 30%. The SiO contained in MFI molecular sieve and MOR molecular sieve is 2.34~2.83% and 1.32~1.33% respectively. 2 and Al2 O 3 The molar ratio is 10-40:1.

[0030] The metal element is any one or more of Group VIII elements, Group I elements or lanthanide metals. Group VIII elements are platinum, palladium, iridium, ruthenium, cobalt and nickel. Group I elements are gold and silver. Lanthanide metal elements are lanthanum and cerium.

[0031] Calculated by weight percentage of the catalyst, the loading amount of the Group VIII element is 0.5% to 2.0%, the loading amount of the Group I element is 0 to 0.25%, and the loading amount of the lanthanide metal element is 0 to 0.25%.

[0032] The preparation method of the catalyst of the present invention is specifically implemented according to the following steps:

[0033] S1, take molecular sieve and γ-Al 2 O 3 The precursor materials are mixed evenly, γ-Al 2 O 3 The dry basis weight accounts for 20% to 30%, and then a peptizing agent and an extrusion aid are added for kneading to obtain a primary product;

[0034] Among them, the molecular sieve is composed of MFI molecular sieve and MOR molecular sieve, the mass of MFI molecular sieve accounts for 70% to 100%, and the mass of MOR molecular sieve accounts for 0 to 30%. The SiO contained in MFI molecular sieve and MOR molecular sieve is 2.34~2.83% and 1.32~1.33% respectively. 2 and Al 2 O 3 The molar ratio is 10 to 40:1;

[0035] γ-Al 2 O 3 The precursor material is aluminum sol or pseudo-boehmite;

[0036] The peptizing agent is an aqueous solution of any one or more of nitric acid, phosphoric acid, citric acid, oxalic acid and formic acid. The mass percentage of the peptizing agent aqueous solution is 2%-8%, and the mass of the peptizing agent accounts for 1.3% of the molecular sieve and γ-Al 2 O 3 25%-50% of the total mass.

[0037] S2, extruding the primary product into a shape, drying it at 80°C to 120°C for 4h to 8h to obtain a dried product, and then calcining the dried product at 520°C to 550°C for 4h to 5h to obtain a catalyst body;

[0038] S3. Immerse the catalyst body and the metal salt solution in equal volumes for 24 to 26 hours, take out and dry at 80 to 120°C for 4 to 8 hours, and finally calcine at 520 to 550°C for 4 to 5 hours to obtain a catalyst for preparing mesitylene.

[0039] The metal element is any one or more of the Group VIII elements, the Group I elements or the lanthanide metals, the Group VIII elements are platinum, palladium, iridium, ruthenium, cobalt and nickel, the Group I elements are gold and silver, and the lanthanide metal elements are lanthanum and cerium. Calculated by weight percentage of the catalyst, the loading amount of platinum, palladium, iridium, ruthenium, cobalt, nickel and other elements is 0.5% to 2.0%, the loading amount of gold and silver elements is 0 to 0.25%, and the loading amount of lanthanum and cerium elements is 0 to 0.25%.

[0040] Example 1

[0041] The catalyst for preparing mesitylene of the present invention comprises the following components: molecular sieve 78.44%, γ-Al 2 O 3 19.61%, metal elements 1.95%.

[0042] Weigh 400g of two molecular sieves, MFI molecular sieve and MOR molecular sieve, respectively, and mix them in a mass ratio of 7:3, wherein the molar ratio of silicon to aluminum in the MFI molecular sieve is 40:1, and the molar ratio of silicon to aluminum in the MOR molecular sieve is 10:1; the mixed molecular sieve and pseudo-boehmite are evenly mixed in a dry basis mass ratio of 80:20, and a 2% nitric acid aqueous solution and 50g of sesbania powder are added for kneading to obtain a primary product, and then the primary product is extruded and molded, and placed at 80°C for drying for 8h to obtain a dried product, and then the dried product is placed at 550°C for calcination for 4h to obtain a catalyst body; the catalyst body is impregnated with an equal volume of a metal salt solution of nickel and lanthanum for 24h, wherein the masses of nickel and lanthanum in the metal salt solution are respectively the dry basis mass after molding (molecular sieve and γ-Al 2 O 3 The intermediate material after drying is placed at 120°C for 4 hours, and finally the dried intermediate material is placed at 550°C for 4 hours to obtain catalyst A. The composition of catalyst A is shown in Table 3.

[0043] Example 2

[0044] The catalyst for preparing mesitylene of the present invention comprises the following components: molecular sieve 78.8%, γ-Al 2 O 3 19.7%, metal elements 1.5%.

[0045] Weigh 400g of MFI molecular sieve and MOR molecular sieve respectively, and mix the two in a mass ratio of 8:2, wherein the molar ratio of silicon to aluminum in the MFI molecular sieve is 28:1, and the molar ratio of silicon to aluminum in the MOR molecular sieve is 25:1; the mixed molecular sieve and aluminum sol are evenly mixed in a dry basis mass ratio of 80:20, and a 5% nitric acid aqueous solution and 10g of sesbania powder are added for bonding to obtain a primary product, and then the primary product is extruded and molded, and placed at 80°C for drying for 8h to obtain a dried product, and then the dried product is placed at 530°C for roasting for 5h to obtain a catalyst body; the catalyst body is impregnated with an equal volume of a metal salt solution of nickel and lanthanum for 26h, wherein the masses of nickel and lanthanum in the metal salt solution are respectively the dry basis mass after molding (molecular sieve and γ-Al 2 O 3 The catalyst B is prepared by drying the intermediate material at 80°C for 8 hours and calcining the dried intermediate material at 520°C for 5 hours to obtain the catalyst B. The composition of the catalyst B is shown in Table 3.

[0046] Example 3

[0047] The catalyst for preparing mesitylene of the present invention comprises the following components: molecular sieve 68.6%, γ-Al 2 O 3 29.4%, metal elements 2%.

[0048] Weigh 400g of two molecular sieves, MFI molecular sieve and MOR molecular sieve, respectively, and mix them in a mass ratio of 9:1, wherein the molar ratio of silicon to aluminum in the MFI molecular sieve is 28:1, and the molar ratio of silicon to aluminum in the MOR molecular sieve is 25:1; the mixed molecular sieve and aluminum sol are evenly mixed in a dry basis mass ratio of 70:30, and a 2% nitric acid aqueous solution and 60g of graphite powder are added for kneading to obtain a primary product, and then the primary product is extruded and molded, and placed at 100°C for drying for 6h to obtain a dried product, and then the dried product is placed at 550°C for calcination for 4h to obtain a catalyst body; the catalyst body is impregnated with an equal volume of a metal salt solution of nickel and lanthanum for 25h, wherein the mass of the nickel element in the metal salt solution is the dry basis mass after molding (molecular sieve and γ-Al 2 O 3 The intermediate material after drying was placed at 100°C for 6 hours, and finally the dried intermediate material was placed at 540°C for 4 hours to obtain catalyst C. The composition of catalyst C is shown in Table 3.

[0049] Example 4

[0050] The catalyst for preparing mesitylene of the present invention comprises the following components: molecular sieve 78.36%, γ-Al 2 O3 19.59%, metal elements 2.05%.

[0051] Weigh 400g of MFI molecular sieve, wherein the molar ratio of silicon to aluminum in the MFI molecular sieve is 40:1, mix the molecular sieve and aluminum sol at a dry basis mass ratio of 80:20, add 8% nitric acid aqueous solution and 60g sesbania powder for kneading to obtain a primary product, then extrude the primary product, dry it at 120°C for 4h to obtain a dried product, then calcine the dried product at 520°C for 5h to obtain a catalyst body; impregnate the catalyst body with equal volumes of metal salt solutions of nickel and silver for 26h, wherein the masses of nickel and silver in the metal salt solution are respectively the dry basis mass after molding (molecular sieve and γ-Al 2 O 3 The catalyst D is 2% and 0.05% of the total mass of the catalyst, which is taken out and dried at 120°C for 4 hours. Finally, the dried intermediate material is calcined at 550°C for 4 hours to obtain the catalyst D. The composition of the catalyst D is shown in Table 3.

[0052] Example 5

[0053] The catalyst for preparing mesitylene of the present invention comprises the following components: molecular sieve 78.2%, γ-Al 2 O 3 19.55%, metal elements 2.25%.

[0054] Weigh 400g of two molecular sieves, MFI molecular sieve and MOR molecular sieve, respectively, and mix them in a mass ratio of 9:1, wherein the molar ratio of silicon to aluminum in the MFI molecular sieve is 28:1, and the molar ratio of silicon to aluminum in the MOR molecular sieve is 10:1; the mixed molecular sieve and aluminum sol are evenly mixed in a dry basis mass ratio of 80:20, and a 5% nitric acid aqueous solution and 30g of sesbania powder are added for kneading to obtain a primary product, and then the primary product is extruded and molded, and placed at 120°C for drying for 4h to obtain a dried product, and then the dried product is placed at 520°C for roasting for 5h to obtain a catalyst body; the catalyst body is impregnated with an equal volume of a mixed solution of nickel nitrate, silver nitrate and lanthanum nitrate for 24h, wherein the masses of nickel element, silver element and lanthanum element in the metal salt solution are respectively the dry basis mass after molding (molecular sieve and γ-Al 2 O 3 The intermediate material after drying was immersed in an equal volume of silver nitrate solution for 24 hours, wherein the silver element loading amount in the silver nitrate was 0.25%, and it was taken out and dried at 120°C for 4 hours. Finally, the dried material was calcined at 520°C for 4 hours to obtain catalyst E. The composition of catalyst E is shown in Table 3.

[0055] Comparative Example 1

[0056] Take SiO 2 With Al 2 O 3 The molar ratio of EUO molecular sieve and γ-Al is 30:1 2 O 3 The powders were mixed at a dry weight ratio of 65:35, and then added with a 2% nitric acid aqueous solution to form strips. 2 O 3 The mass ratio of the total mass to nitric acid is 10:3, followed by drying in the shade for 24 hours, drying at 120°C for 3 hours, and calcining at 540°C for 4 hours. The catalyst F was obtained by impregnating with a mixed solution of chloroplatinic acid and palladium chloride for 24 hours, the concentration of the chloroplatinic acid solution was 0.008%, the concentration of the palladium chloride solution was 0.05%, and then drying at 110°C for 5 hours, and then impregnating with an equal volume of 0.1% ammonium molybdate solution for 12 hours, the concentration of the ammonium molybdate solution was 0.1%, and then standing at 60°C for 4 hours, drying at 110°C for 3 hours, and then calcining at 550°C for 4 hours to obtain catalyst F. The composition of catalyst F is shown in Table 4.

[0057] Comparative Example 2

[0058] Take SiO 2 With Al 2 O 3 The molar ratio of EUO molecular sieve and γ-Al is 35:1 2 O 3 The powders were mixed at a dry weight ratio of 60:40, and then added with a 2% nitric acid aqueous solution to form strips. 2 O 3 The mass ratio of the total mass to nitric acid is 10:3, followed by drying in the shade for 24 hours, drying at 120°C for 3 hours, and calcining at 540°C for 4 hours. The catalyst F was obtained by impregnating with a mixed solution of chloroplatinic acid and palladium chloride for 24 hours, the concentration of the chloroplatinic acid solution was 0.008%, the concentration of the palladium chloride solution was 0.05%, and then drying at 110°C for 5 hours, and then impregnating with an equal volume of 0.1% ammonium molybdate solution for 12 hours, the concentration of the ammonium molybdate solution was 0.1%, and then standing at 60°C for 4 hours, drying at 90°C for 5 hours, and then calcining at 550°C for 4 hours to obtain catalyst F. The composition of catalyst F is shown in Table 4.

[0059] Comparative Example 3

[0060] Take SiO 2 With Al 2 O 3 The molar ratio of EUO molecular sieve and γ-Al is 40:1 2 O 3The powders were mixed at a dry weight ratio of 55:45, and then added with a 2% nitric acid aqueous solution to form strips. 2 O 3 The mass ratio of the total mass to nitric acid is 10:3, followed by drying in the shade for 24 hours, drying at 120°C for 3 hours, and calcining at 540°C for 4 hours. The catalyst H was obtained by impregnating with a mixed solution of chloroplatinic acid and palladium chloride for 24 hours, the concentration of the chloroplatinic acid solution was 0.008%, the concentration of the palladium chloride solution was 0.05%, and then drying at 110°C for 5 hours, and then impregnating with an equal volume of 0.1% ammonium molybdate solution for 12 hours, the concentration of the ammonium molybdate solution was 0.1%, and then standing at 60°C for 4 hours, drying at 100°C for 4 hours, and then calcining at 550°C for 4 hours to obtain catalyst H. The composition of catalyst H is shown in Table 4.

[0061] Comparative Example Evaluation Method: Catalyst F, Catalyst G, and Catalyst H were placed in a hydrogen atmosphere and reduced at 500°C for 4 hours, and the isomerization reaction was evaluated in a fixed bed reactor using trimethylol as the raw material. The inner diameter of the reactor was 20 mm, the catalyst loading was 25 g, and the reaction conditions were: temperature 360°C, pressure 0.5 MPa, hydrogen-to-hydrocarbon ratio 600 v / v, and mass space velocity 3.0 h-1. The raw material composition, catalyst composition, and reaction results used in each comparative example are shown in Table 2, Table 4, and Table 5, respectively.

[0062] Example Evaluation method:

[0063] The prepared catalyst was loaded in a fixed bed reactor with an inner diameter of 10 mm and a catalyst loading of 10 ml. The catalyst was first placed in a hydrogen atmosphere at 500 ° C for 4 h for reduction, and then the isomerization reaction was carried out with trimethylol as the raw material. Evaluation: The trimethylol raw material was sent into a fixed bed reactor filled with the catalyst for reaction. Under a hydrogen atmosphere, the reaction temperature was 280-320 ° C, the pressure was 1.0-1.8 MPa, and the volume space velocity was 0.8-1.5 h -1 .

[0064]

[0065]

[0066]

[0067] Evaluation of each example

[0068] The raw material composition, catalyst composition and reaction results used in each example are shown in Table 1, Table 3 and Table 5 respectively.

[0069] Example 1 Evaluation conditions:

[0070] Temperature 280℃, pressure 1.0MPa, volume space velocity 1.5h-1 .

[0071] Example 2 Evaluation conditions:

[0072] Temperature 300℃, pressure 1.5MPa, volume space velocity 1.2h -1 .

[0073] Example 3 Evaluation conditions:

[0074] Temperature 320℃, pressure 1.5MPa, volume space velocity 1.0h -1 .

[0075] Evaluation Example 4 Evaluation conditions:

[0076] Temperature 320℃, pressure 1.2MPa, volume space velocity 0.8h -1 .

[0077] Evaluation Example 5 Evaluation conditions:

[0078] Temperature 320℃, pressure 1.8MPa, volume space velocity 0.8h -1 .

[0079] Table 1 Example Raw Material Composition

[0080] composition Mesitylene o-Methylethylbenzene Trimethylol Trimethylol content / % 0.207 0.172 99.343 0.277

[0081] Table 2 Comparative Example Raw Material Composition

[0082] composition Trimethylol Mesitylene Trimethylol other content / % 98.73 0.13 0.45 0.69

[0083] Table 3 Example catalyst composition

[0084]

[0085]

[0086] Table 4 Comparative Example Catalyst Composition

[0087]

[0088] Table 5 Reaction result data

[0089]

[0090] It can be seen from the above table that: in the comparative examples (E, F, G), when the reaction temperature is high (360°C), the mesitylene selectivity does not exceed 60%. When the mesitylene yield is equivalent, the unsymmetrical trimethylol conversion rate is high and the mesitylene selectivity is low, resulting in waste of heat and raw materials. However, the mesitylene catalyst prepared in the present invention has a low reaction temperature and still has a high mesitylene selectivity, the mesitylene selectivity is above 60%, the highest reaching 67.3%, the mesitylene yield can reach up to 24.5%, the unsymmetrical trimethylol conversion rate is low and the mesitylene selectivity is high, and in the process of raw material recycling, the waste of raw materials is greatly reduced.

[0091] The present invention has been disclosed in the above preferred embodiments, but those skilled in the art should understand that these embodiments are only used to describe the present invention and should not be construed as limiting the scope of the present invention. Further improvements can be made without departing from the principles of the present invention, and these improvements should also be regarded as protections of the present invention.

Claims

1. A catalyst for preparing mesitylene, characterized in that: According to mass percentage, it is composed of the following components: molecular sieve 65% to 80%, γ-Al2O3 15% to 30%, and metal elements 0.25% to 2.5%, and the sum of the mass percentages of the above components is 100%.

2. The catalyst for preparing mesitylene according to claim 1, characterized in that: The molecular sieve is composed of MFI type molecular sieve and MOR type molecular sieve, the mass of the MFI type molecular sieve accounts for 70% to 100%, the mass of the MOR type molecular sieve accounts for 0 to 30%, and the molar ratio of SiO2 and Al2O3 contained in the MFI type molecular sieve and the MOR type molecular sieve is 10 to 40:

1.

3. The catalyst for preparing mesitylene according to claim 1, characterized in that: The metal element is any one or more of a Group VIII element, a Group I element or a lanthanide metal, the Group VIII element is platinum, palladium, iridium, ruthenium, cobalt or nickel, the Group I element is gold or silver, and the lanthanide metal is lanthanum or cerium.

4. The catalyst for preparing mesitylene according to claim 3, characterized in that: Calculated by weight percentage of the catalyst, the loading amount of the Group VIII element is 0.5% to 2.0%, the loading amount of the Group I element is 0 to 0.25%, and the loading amount of the lanthanide metal is 0 to 0.25%.

5. A method for preparing a catalyst for preparing mesitylene, characterized in that: Follow the steps below to implement it: S1, respectively taking molecular sieve and γ-Al2O3 precursor material and mixing them evenly, wherein the dry basis weight of γ-Al2O3 accounts for 20% to 30%, and then adding peptizing agent and extrusion aid to knead them to obtain a primary product; S2, extruding the primary product into a shape, drying it at 80°C to 120°C for 4h to 8h to obtain a dried product, and then calcining the dried product at 520°C to 550°C for 4h to 5h to obtain a catalyst body; S3. Immerse the catalyst body and the metal salt solution in equal volumes for 24 to 26 hours, take out and dry at 80 to 120°C for 4 to 8 hours, and finally calcine at 520 to 550°C for 4 to 5 hours to obtain a catalyst for preparing mesitylene.

6. The method for preparing a catalyst for preparing mesitylene according to claim 5, characterized in that: The molecular sieve is composed of MFI type molecular sieve and MOR type molecular sieve, the mass of the MFI type molecular sieve accounts for 70% to 100%, the mass of the MOR type molecular sieve accounts for 0 to 30%, and the molar ratio of SiO2 and Al2O3 contained in the MFI type molecular sieve and the MOR type molecular sieve is 10 to 40:

1.

7. The method for preparing a catalyst for preparing mesitylene according to claim 5, characterized in that: The γ-Al2O3 precursor material is aluminum sol or pseudo-boehmite.

8. The method for preparing a catalyst for preparing mesitylene according to claim 5, characterized in that: The peptizing agent in step 1 is an aqueous solution of any one or more of nitric acid, phosphoric acid, citric acid, oxalic acid and formic acid, the mass percentage of the aqueous solution of the peptizing agent is 2%-8%, and the mass of the peptizing agent accounts for 25%-50% of the total mass of the molecular sieve and γ-Al2O3.

9. The method for preparing a catalyst for preparing mesitylene according to claim 5, characterized in that: The extrusion aid in step 1 is any one or more of polyol, sesbania powder or graphite, and the mass of the extrusion aid accounts for 2%-15% of the total mass of the molecular sieve and γ-Al2O3.

10. The method for preparing a catalyst for preparing mesitylene according to claim 5, characterized in that: The metal element in step 3 is any one or more of group VIII elements, group I elements or lanthanide metals, the group VIII elements are platinum, palladium, iridium, ruthenium, cobalt, and nickel, the group I elements are gold and silver, and the lanthanide metal elements are lanthanum and cerium. In terms of catalyst weight percentage, the loading amount of the platinum, palladium, iridium, ruthenium, cobalt, and nickel elements is 0.5% to 2.0%, the loading amount of the gold and silver elements is 0 to 0.25%, and the loading amount of the lanthanum and cerium elements is 0 to 0.25%.

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