Preparation method of catalyst for catalyzing directional polycondensation of acetone to produce mesitylene and isophorone

Abstract

The invention discloses a preparation method of a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone, and belongs to the technical field of catalysis, a magnesium-aluminum-zinc composite oxide is prepared by adopting a coprecipitation method, an active component and a metal modification additive component are synchronously introduced in the coprecipitation process, drying and roasting are performed, and the finished product catalyst is prepared. According to the invention, the efficient synergistic effect of the active metal component and the additive metal component on the composite alkaline oxide is realized, and the distribution of acid-base sites of the catalyst is modulated, so that the effect of co-production of isophorone and mesitylene by directional polycondensation of acetone is achieved. The catalyst prepared by the method is suitable for catalyzing acetone polycondensation to co-produce isophorone and mesitylene, and has the advantages of simple preparation process, high catalytic activity, good stability and the like.

Description

Technical Field

[0001] The invention relates to the technical field of organic catalysts, and more specifically to a method for preparing a catalyst for catalyzing directional polycondensation of acetone to produce mesitylene and isophorone. Background Art

[0002] Isophorone has a high boiling point and low hygroscopicity. It has good solubility, dispersibility and leveling properties. It is a good solvent for polymer materials and can dissolve nitrocellulose, acrylates, alkyd resins, polyesters and epoxy resins. It is an intermediate for various important products such as alcohols, acids, amines, esters and isocyanates, and has a wide range of uses in industries such as plastics, pesticides, medicines, and coatings.

[0003] At present, the preparation methods of isophorone mainly include the mesityl oxide method and the acetone condensation method. Among them, the mesityl oxide method has the characteristics of mild reaction conditions, simple process, and convenient operation, but its raw material price is relatively expensive and difficult to promote and apply. The acetone gas-solid multiphase condensation method has low raw material cost and broad industrialization prospects, and is the most advantageous synthesis method.

[0004] Mesitylene is an important chemical raw material, which can be used to prepare a variety of fine chemical products such as dye intermediate mesitylene amine, antioxidant Lonox330 and anti-ultraviolet oxidation stabilizer mesitylene phenol. It is also an important raw material for the production of alkyd resin and high-temperature plasticizer.

[0005] The synthesis method of mesitylene is relatively mature. The traditional synthesis methods mainly include: extractive distillation method, heavy aromatic hydrocarbon distillation separation method, gas phase isomerization reaction of mesitylene, atmospheric pressure liquid phase isomerization reaction of mesitylene, atmospheric pressure liquid phase alkylation of mesitylene to produce mesitylene and co-production of mesitylene, and combined isomerization and alkylation of mesitylene to produce high-purity mesitylene and co-production of mesitylene, etc.

[0006] The process route of preparing mesitylene from acetone by heterogeneous catalysis has the advantages of environmental protection and easy industrialization. However, due to the complexity of the acetone condensation process, it has many by-products and low selectivity for mesitylene. At present, the catalysts for condensation trimer of acetone are mainly divided into two categories. One category is mainly based on solid alkaline magnesium-aluminum composite oxides, which are used to catalyze the condensation of acetone to produce dimer isoacetone alcohol or further trimerized phorone and isophorone. US5153156 patent reports a catalyst that sprays synthetic clay on the surface of MgO-Al2O3 by spraying. The selectivity for catalyzing condensation of acetone to mesitylene oxide and isophorone is low at 27.3%. In CN109926040A patent, a template agent is used to prepare a composite oxide of modified metal and magnesium-aluminum by precipitation method. In the reaction of condensation of acetone to prepare isophorone, the reaction temperature is 250℃~300℃, and the mass space velocity of acetone is 1~8h under normal pressure. -1, the highest acetone conversion rate is 45%, the selectivity of isophorone is 75%, and the selectivity of isophorone and mesityl oxide is 90%. Another type of solid acid mainly composed of modified aluminosilicate zeolites loaded with metal oxides can be used to catalyze the condensation of acetone with mesitylene and benzene ring-containing compounds. US2917561A patent reports an active component loaded with metal tantalum, and the carrier uses a zeolite with a porous structure as a catalyst for the heterogeneous acetone condensation process. US5087781A patent reports a metal Nb catalyst loaded on a silica-alumina carrier. When the loading amount of Nb is 2wt%, a 30% acetone conversion rate is achieved, and the selectivity for mesitylene is 65%.

[0007] According to the existing research and patents, the catalyst for acetone polycondensation mainly focuses on achieving the conversion of a single target product, mesitylene or isophorone, and has the disadvantages of low acetone conversion rate, short catalyst life, low catalytic efficiency, low selectivity of mesitylene and isophorone. There is still a large technical gap in the technology of catalyzing acetone polycondensation to co-produce isophorone and mesitylene. At present, there is a lack of a catalyst that can simultaneously and efficiently catalyze the condensation of acetone to co-produce isophorone and mesitylene. In order to further improve the conversion rate of acetone polycondensation and the yield of isophorone and mesitylene, the key technology of this patented process adopts the coprecipitation method of the base catalyst for improving the acetone catalytic polycondensation of isophorone, and the acid catalytic active metal component and the auxiliary metal component are introduced in the coprecipitation process to develop a new type of catalyst for realizing the directional polycondensation of acetone to co-produce isophorone and mesitylene with an acid-base position distribution with efficient synergistic effect. Summary of the invention

[0008] Based on previous research and existing problems, the present invention proposes a preparation method for a catalyst for catalyzing the directional polycondensation of acetone to produce mesitylene and isophorone after further research and analysis. The magnesium-aluminum-zinc composite oxide is prepared by a coprecipitation method, and the active component and the metal modification auxiliary component are simultaneously introduced during the coprecipitation process, so that the efficient synergistic effect of the active metal component and the auxiliary metal component on the composite alkaline oxide and the distribution of the acid and base positions of the catalyst are adjusted, thereby achieving the effect of directional polycondensation of acetone to produce isophorone and mesitylene.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A method for preparing a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone, comprising the following steps:

[0011] S1. Preparing composite basic oxide by coprecipitation method;

[0012] S2. During the co-precipitation process, active components and metal modification auxiliary components are simultaneously introduced, dried and calcined to obtain a finished catalyst.

[0013] Preferably, the composite alkaline oxide is a mixture of magnesium oxide, aluminum oxide and zinc oxide, wherein the molar ratio of each oxide as metal element is 1:1 to 3:1 for Mg / Al, 1:1 to 5:1 for Mg / Zn and 1:1 to 3:1 for Al / Zn.

[0014] Preferably, the active component is one or more oxides of Group IVB Ti, Zr, Hf or Group VB V, Nb, Ta or their precursors, and the content of the oxide in the catalyst is 0.5-15 wt%.

[0015] Preferably, the metal modification auxiliary component is one or more oxides of Group VIB Cr, Mo, W or transition metals Fe, Co, Ni, Cu, Zn or their precursors, and the content of the oxide in the catalyst is 1 to 10 wt%.

[0016] Preferably, the specific steps in S1 are as follows:

[0017] Prepare a soluble mixed salt solution of magnesium, aluminum and zinc and dissolve it in water. Add the mixed salt solution and ammonia water dropwise into distilled water at 70-85° C. under stirring, and keep the pH of the reaction system at 9-10.

[0018] Preferably, the specific steps in S2 are as follows:

[0019] S21, prepare a mixed solution of active components and metal modification auxiliary component precursor salts of required concentrations, add the mixed solution to the reaction system of S1, continue stirring for 15 to 20 hours, and then stand for 4 to 8 hours;

[0020] S22, filtering the cooled precipitate, washing with water until neutral, drying, and calcining to obtain a finished catalyst.

[0021] Preferably, the soluble salts of magnesium, aluminum and zinc are magnesium nitrate, aluminum nitrate and zinc nitrate.

[0022] Preferably, the drying conditions in S22 are: drying at 100-120° C. for 10-12 hours; and the calcination conditions are: calcination at 550-600° C. for 6-10 hours.

[0023] The present invention also provides a catalyst prepared by the above-mentioned method, which is used for catalyzing the directional polycondensation of acetone to produce mesitylene and isophorone. The applicable reaction conditions are: the inert gas pressure in the reactor is 0.1-10MPa, the reaction temperature is 250-400°C, and the liquid hourly volume space velocity is 0.5-2.5h -1 .

[0024] Compared with the existing technology, the present invention provides a preparation method of a catalyst for producing mesitylene and isophorone by catalyzing the directional polycondensation of acetone, which has the following beneficial effects:

[0025] (1) The preparation method proposed in the present invention uses a composite alkaline oxide as the catalyst base, and simultaneously introduces an active metal component and an auxiliary component that produces more mesitylene during the co-precipitation preparation process, thereby adjusting the acidity and base position of the catalyst, achieving a highly efficient synergistic effect of the acidity and base of the catalyst, and avoiding the deep polycondensation of acetone to form carbon deposits that lead to a decrease in catalyst activity.

[0026] (2) The catalyst of the present invention can reasonably adjust the amount of active metal components and auxiliary components introduced to achieve the overall distribution of acid and base sites in the catalyst, thereby achieving the production requirements of acetone polycondensation to produce isophorone and mesitylene.

[0027] (3) In addition, the acetone polycondensation production equipment is simple, the boiling point difference between isophorone and mesitylene is large, and the separation cost is low. Compared with the traditional acetone polycondensation process for producing isophorone, the conversion rate of the method proposed in the present invention is greatly improved.

[0028] (4) The prepared catalyst has good activity and selectivity. Under normal pressure conditions, the total selectivity of isophorone and mesitylene can reach more than 90%, and the acetone conversion rate can reach more than 65%.

[0029] (5) The catalyst preparation method is simple, and the catalyst has high activity, strong resistance to carbon deposition, and good stability. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] The present invention provides a preparation method of a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone, comprising the following steps:

[0032] S1. Preparing composite basic oxide by coprecipitation method;

[0033] S2. During the co-precipitation process, active components and metal modification auxiliary components are simultaneously introduced, dried and calcined to obtain a finished catalyst.

[0034] The catalyst is composed of composite alkaline oxide, active component and metal modification auxiliary agent, wherein the composite alkaline oxide is a mixture of magnesium oxide, aluminum oxide and zinc oxide, wherein the molar ratio of each oxide in terms of metal element is 1:1-3:1 for Mg / Al, 1:1-5:1 for Mg / Zn and 1:1-3:1 for Al / Zn. The active component is one or more oxides of Ti, Zr, Hf of group IVB or V, Nb, Ta of group VB or their precursors, and the content of the oxide in the catalyst is 0.5-15wt%. The metal modification auxiliary agent component is one or more oxides of Cr, Mo, W of group VIB or transition metals Fe, Co, Ni, Cu, Zn or their precursors, and the content of the oxide in the catalyst is 1-10wt%.

[0035] In the preparation process, the specific steps are as follows:

[0036] Prepare a soluble mixed salt solution of magnesium, aluminum and zinc and dissolve it in water. Add the mixed salt solution and ammonia water to distilled water at 70-85°C simultaneously under stirring, and keep the pH of the reaction system at 9-10. Continue stirring after the addition is completed. Then prepare a mixed solution of active components and metal modification auxiliary component precursor salts of the required concentration, add the mixed solution to the reaction system of S1, continue stirring for 15-20 hours, and then let it stand for 4-8 hours. Filter the cooled precipitate, wash with water until neutral, dry, and calcine to obtain a finished catalyst.

[0037] The soluble salts of magnesium, aluminum and zinc are magnesium nitrate, aluminum nitrate and zinc nitrate. The drying conditions are: drying at 100-120°C for 10-12 hours; the roasting conditions are: roasting at 550-600°C for 6-10 hours.

[0038] It should be noted that the following embodiments and features in the embodiments may be combined with each other in the absence of conflict; and, based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making any creative work are within the scope of protection of the present disclosure.

[0039] Various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement a device and / or practice a method. In addition, other structures and / or functionality other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0040] Example 1

[0041] Weigh 128g of magnesium nitrate hexahydrate, 250g of aluminum nitrate nonahydrate, and 16g of zinc nitrate hexahydrate and dissolve them in 1000ml of deionized water. Add the mixed salt solution and ammonia water to 80°C distilled water at the same time, and adjust the dropping speed so that the pH value of the solution is about 9.0. After the addition is completed, maintain stirring for 20 hours, and simultaneously add a certain amount of niobium oxalate and zirconium acetate mixed solution under mechanical stirring, and let it stand and cool for 6 hours. Filter and cool to precipitate, and wash with water to a pH of about 7.0. Dry at 110°C for 10 hours and then roast at 550°C for 10 hours. Catalyst precursor A-1 is obtained.

[0042] Example 2

[0043] Weigh 128g of magnesium nitrate hexahydrate, 250g of aluminum nitrate nonahydrate, and 16g of zinc nitrate hexahydrate and dissolve them in 1000ml of deionized water. Add the mixed salt solution and ammonia water to 80°C distilled water at the same time, and adjust the dropping speed so that the pH value of the solution is about 9.0. After the addition is completed, keep stirring for 20 hours, and add a certain amount of niobium oxalate and ammonium metatungstate mixed solution simultaneously under mechanical stirring, and let it stand and cool for 6 hours. Filter and cool to precipitate, and wash with water to a pH of about 7.0. Dry at 110°C for 10 hours and then roast at 550°C for 10 hours. Catalyst precursor A-2 is obtained.

[0044] Example 3

[0045] Weigh 128g of magnesium nitrate hexahydrate, 250g of aluminum nitrate nonahydrate, and 16g of zinc nitrate hexahydrate and dissolve them in 1000ml of deionized water. Add the mixed salt solution and ammonia water to 80°C distilled water at the same time, and adjust the dropping speed so that the pH value of the solution is about 9.0. After the addition is completed, keep stirring for 20 hours, and add a certain amount of tantalum chloride and ammonium molybdate tetrahydrate mixed solution simultaneously under mechanical stirring, and let it stand and cool for 6 hours. Filter and cool the precipitate, and wash with water to a pH of about 7.0. Dry at 110°C for 10 hours and then roast at 550°C for 10 hours. Catalyst precursor A-3 is obtained.

[0046] Example 4

[0047] Weigh 170g of magnesium nitrate hexahydrate, 125g of aluminum nitrate nonahydrate, and 16g of zinc nitrate hexahydrate and dissolve them in 1000ml of deionized water. Add the mixed salt solution and ammonia water to 80°C distilled water at the same time, and adjust the dropping speed so that the pH value of the solution is about 9.0. After the addition is completed, keep stirring for 20 hours, and add a certain amount of niobium oxalate and ammonium metatungstate mixed solution simultaneously under mechanical stirring, and let it stand and cool for 6 hours. Filter and cool to precipitate, and wash with water to a pH of about 7.0. Dry at 110°C for 10 hours and then roast at 550°C for 10 hours. Catalyst precursor A-4 is obtained.

[0048] Example 5

[0049] Weigh 170g of magnesium nitrate hexahydrate, 250g of aluminum nitrate nonahydrate, and 31g of zinc nitrate hexahydrate and dissolve them in 1000ml of deionized water. Add the mixed salt solution and ammonia water to 80°C distilled water at the same time, and adjust the dropping speed so that the pH value of the solution is about 9.0. After the addition is completed, keep stirring for 20 hours, and add a certain amount of niobium oxalate and ammonium metatungstate mixed solution simultaneously under mechanical stirring, and let it stand and cool for 6 hours. Filter and cool to precipitate, and wash with water to a pH of about 7.0. Dry at 110°C for 10 hours and then roast at 550°C for 10 hours. Catalyst precursor A-6 is obtained.

[0050] Evaluation of the catalysts prepared in Examples 1 to 5 for catalyzing the directional polycondensation of acetone to produce isophorone and mesitylene. The specific evaluation process is as follows: Grind the catalyst obtained in the example, take 20g of the catalyst and load it into a fixed bed reactor, inject acetone with a micro pump, and maintain a weight space velocity of 1.0h-1. The reaction temperature is 380℃ and the reaction pressure is 0.1MPa. The reaction product is analyzed by gas chromatography after cooling.

[0051] The reaction evaluation results of the above five catalysts are shown in Table 1:

[0052] Table 1

[0053]

[0054] From the results in Table 1, it can be seen that the catalyst for catalyzing the directional polycondensation of acetone to co-produce isophorone and mesitylene prepared by the method of the present invention has higher trimerization aromatization performance than the conventional catalytic acetone condensation catalyst, produces isophorone and mesitylene at the same time, has a higher conversion rate of raw materials, and has a stronger ability to resist carbon deposition.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A method for preparing a catalyst for catalyzing the directional polycondensation of acetone to produce mesitylene and isophorone, characterized in that: The following steps are involved: S1. Preparing composite basic oxide by coprecipitation method; S2. During the co-precipitation process, active components and metal modification auxiliary components are simultaneously introduced, dried and calcined to obtain a finished catalyst.

2. The method for preparing a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone according to claim 1, characterized in that: The composite alkaline oxide is a mixture of magnesium oxide, aluminum oxide and zinc oxide, wherein the molar ratio of each oxide in terms of metal element is 1:1-3:1 for Mg / Al, 1:1-5:1 for Mg / Zn and 1:1-3:1 for Al / Zn.

3. The method for preparing a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone according to claim 1, characterized in that: The active component is one or more oxides of Ti, Zr, Hf of Group IVB or V, Nb, Ta of Group VB or their precursors, and the content of the oxide in the catalyst is 0.5-15wt%.

4. The method for preparing a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone according to claim 1, characterized in that: The metal modification auxiliary component is one or more oxides of Group VIB Cr, Mo, W or transition metals Fe, Co, Ni, Cu, Zn or their precursors, and the content of the oxide in the catalyst is 1-10wt%.

5. The method for preparing a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone according to claim 2, characterized in that: The specific steps in S1 are as follows: Prepare a soluble mixed salt solution of magnesium, aluminum and zinc and dissolve it in water. Add the mixed salt solution and ammonia water dropwise into distilled water at 70-85° C. under stirring, and keep the pH of the reaction system at 9-10.

6. The method for preparing a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone according to claim 4, characterized in that: The specific steps in S2 are as follows: S21, prepare a mixed solution of active components and metal modification auxiliary component precursor salts of required concentrations, add the mixed solution to the reaction system of S1, continue stirring for 15 to 20 hours, and then stand for 4 to 8 hours; S22, filtering the cooled precipitate, washing with water until neutral, drying, and calcining to obtain a finished catalyst.

7. The method for preparing a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone according to claim 5, characterized in that: The soluble salts of magnesium, aluminum and zinc are magnesium nitrate, aluminum nitrate and zinc nitrate.

8. The method for preparing a catalyst for producing mesitylene and isophorone by catalyzing directional polycondensation of acetone according to claim 5 or 6, characterized in that: The drying conditions in S22 are: drying at 100-120°C for 10-12 hours; the calcination conditions are: calcination at 550-600°C for 6-10 hours.

9. A catalyst prepared by the method according to any one of claims 1 to 8, characterized in that: The catalyst is used to catalyze the directional polycondensation of acetone to produce mesitylene and isophorone. The applicable reaction conditions are: the inert gas pressure in the reactor is 0.1-10MPa, the reaction temperature is 250-400℃, and the liquid hourly volume space velocity is 0.5-2.5h -1 .

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