A method for preparing a catalyst for the catalytic directional polycondensation of acetone to produce mesitylene and isophorone

Abstract

The application discloses a preparation method of a catalyst for catalyzing directional polycondensation of acetone to produce mesitylene and isophorone, and belongs to the field of catalysis technology. The catalyst is prepared by using a co-precipitation method to prepare magnesium-aluminum-zinc composite oxides, and simultaneously introducing active components and metal modified additive components in the co-precipitation process, and then drying and calcining to obtain a finished catalyst. The application realizes efficient synergistic effect of the active metal components and the additive metal components on the composite basic oxides and adjustment of the distribution of acid and base sites of the catalyst, so that the effect of co-producing isophorone and mesitylene through directional polycondensation of acetone is achieved. The catalyst prepared by the method is suitable for catalyzing polycondensation of acetone to co-produce isophorone and mesitylene, and has the advantages of simple preparation process, high catalytic activity and good stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic catalysts, and more particularly to a preparation method of a catalyst for catalyzing the directional polycondensation of acetone to produce mesitylene and isophorone. BACKGROUND

[0002] Isophorone has a high boiling point, low hygroscopicity, good solubility, dispersibility and leveling property, and is a good solvent for high polymer materials, which can dissolve nitrocellulose, acrylate, alkyd resin, polyester and epoxy resin, etc. Isophorone is an important intermediate product of various alcohols, acids, amines, esters and isocyanate, etc., and has a wide range of applications in the plastics, pesticide, medicine and paint industries.

[0003] At present, the preparation methods of isophorone mainly include isopropylidene acetone method and acetone condensation method. The isopropylidene acetone method has the characteristics of mild reaction conditions, simple process and convenient operation, but the raw material price is relatively high, which is difficult to popularize and apply. The acetone gas-solid heterogeneous condensation method has low raw material cost and broad industrialization prospect, and is the most advantageous synthesis method.

[0004] Mesitylene is an important chemical raw material, which can be used to prepare dye intermediate mesitylene aniline, antioxidant Lonox330 and anti-ultraviolet oxidation stabilizer mesitylene phenol and other fine chemical products. It is also an important raw material for producing alkyd resin and high-temperature plasticizer.

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

[0006] The process route of preparing mesitylene from acetone by heterogeneous catalysis method has the advantages of environmental protection and easy industrialization, but due to the complexity of acetone condensation process, there are many by-products, and the selectivity of mesitylene is not high. At present, the catalysts for acetone trimerization are mainly divided into two categories. One is mainly based on solid alkaline magnesium-aluminum composite oxides, which are used to catalyze the condensation of acetone to produce dimer isopropyl ketone or further trimerization of isophorone. US5153156 patent reports a catalyst in which synthetic clay is sprayed on the surface of MgO-Al2O3, which has a low selectivity of 27.3% for catalyzing the condensation of acetone to produce isopropyl ketone and isophorone. In the patent CN109926040A, a modified metal and magnesium-aluminum composite oxide is prepared by a template agent through a precipitation method, which is used in the reaction of acetone condensation to produce isophorone. The reaction temperature is 250-300℃, and the acetone mass space velocity is 1-8h -1, the highest conversion rate of acetone is 45%, the selectivity of isophorone is 75%, and the selectivity of isopropylidene acetone and isophorone is 90%. Another type mainly uses solid acids such as modified silica-alumina zeolite loaded with metal oxides to catalyze the condensation of acetone to trimethylbenzene and compounds containing benzene rings. US2917561A patent reports that a metal tantalum is used as the active component, and a zeolite with a porous structure is used as the carrier to catalyze the heterogeneous condensation of acetone. US5087781A patent reports that a metal Nb catalyst is loaded on a silica-alumina carrier. When the loading amount of Nb is 2wt%, a 30% conversion rate of acetone is achieved, and the selectivity of trimethylbenzene is 65%.

[0007] From the existing research and patents, the catalyst for acetone condensation mainly focuses on achieving single target product trimethylbenzene or isophorone conversion. There are disadvantages such as low conversion rate of acetone, short catalyst life, low catalytic efficiency, and low selectivity of trimethylbenzene and isophorone. There is still a great technical gap in the technology of catalyzing acetone condensation to co-produce isophorone and trimethylbenzene. At present, there is a lack of a catalyst that can simultaneously and efficiently catalyze acetone condensation to co-produce isophorone and trimethylbenzene. In order to further improve the conversion rate of acetone condensation and the yield of isophorone and trimethylbenzene, the key process technology of this patent is to improve the co-precipitation method of the base catalyst for catalyzing acetone to isophorone. Acid-catalyzed active metal components and auxiliary metal components are introduced during the co-precipitation process, and a new type of catalyst with high-efficiency synergistic effect and acid-base site distribution is developed for realizing the directional condensation of acetone to co-produce isophorone and trimethylbenzene. SUMMARY

[0008] Based on the previous research and existing problems, after further research and analysis, a preparation method of a catalyst for catalyzing acetone directional condensation to produce trimethylbenzene and isophorone is proposed. The magnesium-aluminum-zinc composite oxide is prepared by the co-precipitation method, and the active component and metal modification auxiliary component are introduced simultaneously during the co-precipitation process. The high-efficiency synergistic effect of the active metal component and the auxiliary metal component on the composite basic oxide and the adjustment of the acid-base site distribution of the catalyst are realized, so as to achieve the effect of directional condensation of acetone to co-produce isophorone and trimethylbenzene.

[0009] To achieve the above purpose, the technical scheme provided by the present application is as follows:

[0010] A preparation method of a catalyst for catalyzing acetone directional condensation to produce trimethylbenzene and isophorone, comprising the following steps:

[0011] S1, preparing a composite basic oxide by the co-precipitation method;

[0012] S2, introducing the active component and the metal modification auxiliary component simultaneously during the co-precipitation process, drying and calcining to obtain the finished catalyst.

[0013] Preferably, the composite basic oxide is a mixture of magnesium oxide, aluminum oxide and zinc oxide, wherein the molar ratio of Mg / Al is 1:1 to 3:1, the molar ratio of Mg / Zn is 1:1 to 5:1, and the molar ratio of Al / Zn is 1:1 to 3:1, in terms of metal elements.

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

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

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

[0017] A soluble mixed salt solution of magnesium, aluminum and zinc is prepared and dissolved in water, and the mixed salt solution and ammonia are simultaneously added dropwise to distilled water at 70 to 85°C under stirring, and the pH of the reaction system is maintained at 9 to 10.

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

[0019] S21. A mixed solution of active component and metal-modifying auxiliary component precursor salts of a desired concentration is prepared, and the mixed solution is added to the reaction system of S1 and stirred for 15 to 20 hours, and then left to stand for 4 to 8 hours;

[0020] S22. The precipitate after cooling is filtered, washed with water until neutral, dried, and calcined 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 condition in S22 is drying at 100 to 120°C for 10 to 12 hours, and the calcining condition is calcining at 550 to 600°C for 6 to 10 hours.

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

[0024] Compared with the prior art, the present application provides a preparation method of a catalyst for catalyzing the directional condensation polymerization of acetone to produce mesitylene and isophorone, which has the following beneficial effects:

[0025] (1) The preparation method provided by the present application uses a composite basic oxide as a base for the catalyst, and simultaneously introduces active metal components and auxiliary components for producing mesitylene during the co-precipitation preparation process, so as to adjust the acid-base site of the catalyst, realize the efficient synergistic effect of the acid-base of the catalyst, and avoid the formation of coke due to deep polycondensation of acetone, thereby reducing the activity of the catalyst.

[0026] (2) The catalyst in the present application can reasonably adjust the amount of the introduced active metal components and auxiliary components to realize the distribution of the overall acid-base site in the catalyst, thereby realizing the production requirements of acetone polycondensation co-production of 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 production process of isophorone, the conversion rate of the method provided by the present application is greatly improved.

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

[0029] (5) The preparation method of the catalyst is simple, and the catalyst has high activity, strong anti-coking ability, and good stability. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0031] The present application provides a preparation method of a catalyst for catalytic acetone directional polycondensation to produce mesitylene and isophorone, comprising the following steps:

[0032] S1, preparing a composite basic oxide by a co-precipitation method;

[0033] S2, simultaneously introducing active components and metal modification auxiliary components during the co-precipitation process, drying and calcining to obtain a finished catalyst.

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

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

[0036] A soluble mixed salt solution of magnesium, aluminum and zinc is dissolved in water, and the mixed salt solution and ammonia are simultaneously added to distilled water at 70-85°C under stirring, and the pH of the reaction system is maintained at 9-10, after the addition is completed, the stirring is continued, then a mixed solution of the required concentration of the active component and the metal modification auxiliary agent precursor salt is prepared and added to the reaction system of S1 for continuous stirring for 15-20 hours, and then standing for 4-8 hours; the precipitate after cooling is filtered, washed with water to neutral, dried, and calcined to obtain the finished catalyst.

[0037] Among them, the soluble salt of magnesium, aluminum and zinc is magnesium nitrate, aluminum nitrate and zinc nitrate. The drying condition is 100-120°C for 10-12 hours; the calcination condition is 550-600°C for 6-10 hours.

[0038] It should be noted that, in the case of no conflict, the following embodiments and the features in the embodiments can be combined with each other; and based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present disclosure.

[0039] Various aspects of embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms and that any specific structure and / or function described herein is merely illustrative. Based on the disclosure provided herein, one skilled in the art should appreciate that an aspect described herein can be implemented independently of any other aspects and that two or more of these aspects can be combined in any suitable manner. For example, an apparatus can be implemented using any number of the aspects described herein. In addition, an apparatus can be implemented or a method can be practiced using other structure and / or functionality in addition to or other than one or more of the aspects described herein.

[0040] Example 1

[0041] Take 128g magnesium nitrate hexahydrate, 250g aluminum nitrate nonahydrate, 16g zinc nitrate hexahydrate and dissolve them in 1000ml deionized water. The mixed salt solution and ammonia are simultaneously dropped into 80°C distilled water, and the dropping speed is adjusted to make the pH value of the solution about 9.0. After the dropping is completed, the stirring is maintained for 20 hours, and a mixed solution of a certain content of niobium oxalate and zirconium acetate is synchronously added under mechanical stirring, and it is cooled for 6 hours. The precipitate is filtered and washed with water until the pH value is about 7.0. After being dried at 110°C for 10 hours, it is calcined at 550°C for 10 hours. Catalyst precursor A-1 is obtained.

[0042] Example 2

[0043] Take 128g magnesium nitrate hexahydrate, 250g aluminum nitrate nonahydrate, 16g zinc nitrate hexahydrate and dissolve them in 1000ml deionized water. The mixed salt solution and ammonia are simultaneously dropped into 80°C distilled water, and the dropping speed is adjusted to make the pH value of the solution about 9.0. After the dropping is completed, the stirring is maintained for 20 hours, and a mixed solution of a certain content of niobium oxalate and ammonium metatungstate is synchronously added under mechanical stirring, and it is cooled for 6 hours. The precipitate is filtered and washed with water until the pH value is about 7.0. After being dried at 110°C for 10 hours, it is calcined at 550°C for 10 hours. Catalyst precursor A-2 is obtained.

[0044] Example 3

[0045] Take 128g magnesium nitrate hexahydrate, 250g aluminum nitrate nonahydrate, 16g zinc nitrate hexahydrate and dissolve them in 1000ml deionized water. The mixed salt solution and ammonia are simultaneously dropped into 80°C distilled water, and the dropping speed is adjusted to make the pH value of the solution about 9.0. After the dropping is completed, the stirring is maintained for 20 hours, and a mixed solution of a certain content of niobium oxalate and ammonium metatungstate is synchronously added under mechanical stirring, and it is cooled for 6 hours. The precipitate is filtered and washed with water until the pH value is about 7.0. After being dried at 110°C for 10 hours, it is calcined at 550°C for 10 hours. Catalyst precursor A-2 is obtained.

[0046] Example 4

[0047] Take 128g magnesium nitrate hexahydrate, 250g aluminum nitrate nonahydrate, 16g zinc nitrate hexahydrate and dissolve them in 1000ml deionized water. The mixed salt solution and ammonia are simultaneously dropped into 80°C distilled water, and the dropping speed is adjusted to make the pH value of the solution about 9.0. After the dropping is completed, the stirring is maintained for 20 hours, and a mixed solution of a certain content of niobium oxalate and ammonium metatungstate is synchronously added under mechanical stirring, and it is cooled for 6 hours. The precipitate is filtered and washed with water until the pH value is about 7.0. After being dried at 110°C for 10 hours, it is calcined at 550°C for 10 hours. Catalyst precursor A-2 is obtained.

[0048] Example 5

[0049] Example 5

[0050] The catalysts prepared in Examples 1-5 were evaluated for catalyzing the directional condensation of acetone to coproduce isophorone and mesitylene. The evaluation was carried out as follows: the catalyst obtained in the examples was ground and 20 g of the catalyst was loaded into a fixed bed reactor. Acetone was injected into the reactor by means of a micro pump, and the weight hourly space velocity was maintained at 1.0 h-1. The reaction temperature was 380°C, and the reaction pressure was 0.1 MPa. The reaction products were analyzed by gas chromatography after cooling.

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

[0052] Table 1

[0053]

[0054] As shown in Table 1, the catalyst for catalyzing the directional condensation of acetone to coproduce isophorone and mesitylene prepared according to the method of the present application has higher trimerization aromaticity than the conventional catalyst for catalyzing the condensation of acetone, and can produce isophorone and mesitylene simultaneously, has higher conversion of raw materials, and has stronger resistance to carbon deposition.

[0055] The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, the technical solutions described in the foregoing examples can still be modified by those of ordinary skill in the art, or some of the technical features can be replaced by equivalent features; and such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present application.

Claims

1. A method for preparing a catalyst for the directional polycondensation of acetone to produce mesitylene and isophorone, characterized in that, Includes the following steps: S1. Composite basic oxides were prepared by co-precipitation method; S2. Active components and metal-modified additives are introduced simultaneously during the co-precipitation process, followed by drying and calcination to obtain the finished catalyst. The composite alkaline oxide is a mixture of magnesium oxide, aluminum oxide and zinc oxide, wherein the molar ratio of each oxide based on metal element is Mg / Al 1:1 to 3:1, Mg / Zn 1:1 to 5:1, and Al / Zn 1:1 to 3:

1. The active component is one or more oxides or precursors of Group IVB Ti, Zr, Hf or Group VB V, Nb, Ta, and the content in the catalyst, calculated as oxide, is 0.5~15 wt%. The metal-modifying additive component is one or more of the oxides or precursors of Group VIB Cr, Mo, W or transition metals Fe, Co, Ni, Cu, Zn, and the content in the catalyst, calculated as oxide, is 1~10 wt%; The roasting conditions in S2 are 550~600°C.

2. The method for preparing a catalyst for the directional polycondensation of acetone to produce mesitylene and isophorone according to claim 1, characterized in that, The specific steps in S1 are as follows: Prepare a soluble mixed salt solution of magnesium, aluminum, and zinc by dissolving it in water. Under stirring conditions, add the mixed salt solution and ammonia water dropwise to distilled water at 70-85°C, and maintain the pH of the reaction system at 9-10.

3. The method for preparing a catalyst for the directional polycondensation of acetone to produce mesitylene and isophorone according to claim 1, characterized in that, The specific steps in S2 are as follows: S21. Prepare a mixed solution of active component and metal modifier precursor salt of the required concentration. Add the mixed solution to the reaction system of S1 and continue stirring for 15-20 hours, then let it stand for 4-8 hours. S22. After filtering and cooling, the precipitate is washed with water until neutral, dried, and calcined to obtain the finished catalyst.

4. The method for preparing a catalyst for the directional polycondensation of acetone to produce mesitylene and isophorone according to claim 3, characterized in that, Soluble salts of magnesium, aluminum, and zinc are magnesium nitrate, aluminum nitrate, and zinc nitrate.

5. A method for preparing a catalyst for the directional polycondensation of acetone to produce mesitylene and isophorone according to claim 3 or 4, characterized in that, The drying conditions for S22 are: drying at 100~120°C for 10~12 hours; and calcination in S2 for 6~10 hours.

6. A catalyst, prepared by the method according to any one of claims 1-5, characterized in that, The catalyst is used for the directional polycondensation of acetone to produce mesitylene and isophorone. Suitable reaction conditions include an inert gas pressure of 0.1–10 MPa in the reactor, a reaction temperature of 250–400 °C, and a liquid hourly space velocity of 0.5–2.5 h⁻¹. -1 .

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