CN-121988331-A - Supported catalyst and application thereof in synthesis of 1, 3-cyclohexanedione

Abstract

The application provides a supported catalyst and application thereof in synthesis of 1, 3-cyclohexanedione, and belongs to the technical field of chemical synthesis. Adding Zr salt, ni salt, ce salt and Cu salt into citric acid aqueous solution in turn under stirring to obtain clear mixed solution, stirring the mixed solution in water bath to gel state, drying to obtain xerogel, calcining the xerogel to obtain precursor, and reducing the precursor in H 2 /Ar gas flow to obtain the supported catalyst. The supported catalyst is used for synthesizing 1, 3-cyclohexanedione and has the advantages of high selectivity, less byproducts and the like.

Inventors

• SHEN YONGMIAO
• LUO JINGYI
• Mei Kaiyu
• XI ZIWEI
• TANG RENHE

Assignees

• 浙江理工大学

Dates

Publication Date

20260508

Application Date

20260409

Claims (10)

1. 1. A supported catalyst is characterized by comprising the following preparation steps: Sequentially adding Zr salt, ni salt, ce salt and Cu salt into a citric acid aqueous solution under a stirring state to obtain a clear mixed solution; step two, stirring the mixed solution in a water bath until the mixed solution is gel, and drying to obtain xerogel; And thirdly, calcining the xerogel to obtain a precursor, and reducing the precursor in H 2 /Ar gas flow to obtain the supported catalyst.
2. 2. The supported catalyst of claim 1, wherein the concentration of the aqueous solution of citric acid is 5-10 g/ml.
3. 3. The supported catalyst of claim 1, wherein the Zr salt, the Ni salt, the Ce salt and the Cu salt are nitrate.
4. 4. The supported catalyst of claim 1, wherein the addition ratio of Zr salt, ni salt, ce salt and Cu salt is 10:0.8-1.2:0.4-0.6:0.4-0.6.
5. 5. The supported catalyst of claim 1, wherein the calcination is divided into two sections, the first section is calcined at 300-360 ℃ for 1-2 hours, and after the first section is calcined, the first section is cooled to room temperature and then is calcined at 480-550 ℃ for 3-6 hours.
6. 6. The supported catalyst of claim 1, wherein the temperature of the reduction is 300-500 ℃.
7. 7. An application of the supported catalyst in the synthesis of 1, 3-cyclohexanedione, which is characterized in that resorcinol, organic base, water and the supported catalyst are added into a high-pressure reaction kettle, argon and hydrogen are introduced for replacement, the supported catalyst is removed after catalytic hydrogenation reaction, and solution obtained by adding protonic acid for stirring reaction is distilled and dried in vacuum to obtain the 1, 3-cyclohexanedione.
8. 8. The application of claim 7, wherein the addition amount of the supported catalyst is 5-10% of the mass of resorcinol, and the molar ratio of resorcinol to organic base is 1:0.5-2.
9. 9. The method of claim 7, wherein the catalytic hydrogenation reaction is carried out at a temperature of 60-100 ℃ and a pressure of 1-3 MPa.
10. 10. The method according to claim 7, wherein the protonic acid is hydrochloric acid, nitric acid or sulfuric acid.

Description

Supported catalyst and application thereof in synthesis of 1, 3-cyclohexanedione Technical Field The application relates to a supported catalyst and application thereof in synthesis of 1, 3-cyclohexanedione, and belongs to the technical field of chemical synthesis. Background 1, 3-Cyclohexanedione is an important chemical intermediate and has a wide variety of applications in the synthesis of valuable compounds, widely used in the synthesis of pharmaceutical, agrochemical, cosmetic and polymeric additives. Depending on the availability of raw materials, it is generally manufactured in two ways: the first is an aldol condensation process, which uses gamma-acyl carboxylic acid or alpha, beta-unsaturated carboxylic acid ester and ketone as raw materials, and produces 1, 3-cyclohexanedione by intramolecular or intermolecular condensation with a strongly basic condensing agent (U.S. Pat. No. 4,4695673 A1; 1987). The second catalytic hydrogenation process, such as selective hydrogenation of resorcinol with Pd/C catalyst to synthesize 1, 3-cyclohexanedione, is also the primary process for the production of 1, 3-cyclohexanedione. However, this process typically produces byproducts such as 3-hydroxycyclohexanone and 1, 3-cyclohexanediol (chem. Commun,2008,8,999) due to the overhydrogenation. Or the Raney nickel catalyst is used for selectively hydrogenating resorcinol to synthesize the 1, 3-cyclohexanedione, but the cycle times are only 2-3 times, and the catalyst recovery problem and the storage problem are problems although the cost is low, so that the Raney nickel catalyst is easy to catch fire in the air. Thus, achieving high selectivity to 1, 3-cyclohexanedione, especially at elevated resorcinol conversions, remains a significant challenge. Disclosure of Invention In view of the above, the application firstly provides a novel catalyst which is used for hydrogenation reaction, reduces the generation of byproducts, and has the advantages of low cost, high cycle times, stable catalytic performance and the like. Specifically, the application is realized by the following scheme: A supported catalyst is prepared by the following steps: Sequentially adding Zr salt, ni salt, ce salt and Cu salt into a citric acid aqueous solution under a stirring state to obtain a clear mixed solution; step two, stirring the mixed solution in a water bath until the mixed solution is gel, and drying to obtain xerogel; And thirdly, calcining the xerogel to obtain a precursor, and reducing the precursor in H 2/Ar gas flow to obtain the supported catalyst. Further, as preferable: The concentration of the citric acid aqueous solution is 5-10 g/ml. The Zr salt, the Ni salt, the Ce salt and the Cu salt are nitrate. The addition ratio of Zr salt, ni salt, ce salt and Cu salt is 10:0.8-1.2:0.4-0.6:0.4-0.6, preferably 10:1:0.5:0.5. The calcination is divided into two sections, wherein the first section is calcined for 1-2 hours at 300-360 ℃, and after the first section is calcined, the first section is cooled to room temperature and then is calcined for 3-6 hours at 480-550 ℃. The temperature of the reduction is 300-500 ℃. The supported catalyst takes nickel as a main component, so that the cost of the catalyst can be obviously reduced, the catalyst has extremely high selectivity, conversion rate and high recycling rate for the catalytic hydrogenation of resorcinol, the byproducts generated by excessive hydrogenation are reduced, the process is simple, the storage is convenient, and the cycle number is far greater than that of Raney nickel. Meanwhile, the application also provides application of the supported catalyst in synthesis of 1, 3-cyclohexanedione, wherein resorcinol, organic base, water and the supported catalyst are added into a high-pressure reaction kettle, argon and hydrogen are introduced for replacement, the supported catalyst is removed after catalytic hydrogenation reaction, and solution obtained by stirring reaction with protonic acid is added for rotary evaporation and vacuum drying, so that 1, 3-cyclohexanedione is obtained. Preferably: The addition amount of the supported catalyst is 5-10% of the mass of resorcinol. And preferably 6%. The mol ratio of the resorcinol to the organic base is 1:0.5-2. And preferably 1:1. The organic base is sodium hydroxide, potassium hydroxide or lithium hydroxide, and sodium hydroxide is preferred. The reaction temperature of the catalytic hydrogenation is 60-100 ℃, and the reaction pressure is 1-3 MPa. And the reaction effect is optimal at 80 ℃ and 1.5 MPa. The protonic acid is hydrochloric acid, nitric acid or sulfuric acid. And hydrochloric acid is preferred. The catalyst provided by the application has high activity on reduction of 1, 3-cyclohexanedione while reducing cost, can realize synthesis of high-yield and high-purity 1, 3-cyclohexanedione, and shows the best economic advantage. Drawings In order to more clearly illustrate the technical solutions of the embodiments of the present ap