Catalyst, process for its preparation and use

Abstract

The application provides a catalyst and a preparation method and application thereof, the catalyst comprising a carrier and an active component supported on the carrier through chemical bonding; wherein the carrier is aminated polystyrene; and the active component is metal palladium. The catalyst prepared by using the application has excellent catalytic effect when applied to a hydrogenation reaction process of (2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal), is easy to separate for repeated use, and can still maintain excellent catalytic performance in the repeated application process.

Description

Technical Field

[0001] This invention relates to the field of catalytic hydrogenation technology, and more specifically, to a catalyst, its preparation method, and its application. Background Technology

[0002] Ambergris, as one of the most valuable animal-derived fragrances, is considered one of the four major animal fragrances, along with musk, civet, and sea hyacinth. It possesses a balanced aroma and long-lasting fixative properties, and also has medicinal effects such as tonic, anti-inflammatory, and analgesic effects. Because ambergris is essentially a stone formed in the intestines of sperm whales after disease, its availability is extremely limited due to the limited number of sperm whales, making it expensive and in high demand. Based on this, researchers have studied the main components and aroma of ambergris tincture, a substitute for ambergris. They found that it mainly includes (-)-α-ambromide, (+)-γ-dihydroionone, γ-ambromide aldehyde, γ-cyclosporine chloride, and (-)-ambromide ether. Among them, (-)-ambromide ether has a mild, delicate, and long-lasting animalic aroma, accompanied by a distinct woody scent, exhibiting the same fragrance as ambergris. Therefore, (-)-ambroxan has become a substitute for ambergris and is used as a fragrance in perfumes, flavorings and daily chemical products.

[0003] The industrial synthesis of ambroxol primarily uses perillaldehyde (which has a similar carbon skeleton structure to ambroxol) as a raw material. Through oxidation, reduction, and cyclization reactions, perillaldehyde is oxidized to perillyl lactone, then reduced to the corresponding diol, and finally dehydrated and cyclized to form (-)-ambroxol. However, because perillaldehyde is mainly derived from perilla leaves, its preparation involves solvent extraction, steam distillation, residue dewaxing, and recrystallization, making the process complex and costly, thus resulting in its high price.

[0004] In recent years, many scholars have explored synthetic methods for ambroxol, aiming to develop a green and efficient synthetic route. For example, European patent EP0550889B1 discloses a method using β-ionone as a raw material, which involves catalytic hydrogenation, Grignard reaction, esterification, and hydrolysis to generate β-monocyclic high-harmonic acid, followed by cyclization and hydrolysis to generate (±)-2,5,5,8a-tetramethyl-1-carboxymethyl-2-hydroxydecahydronaphthalene, and finally reduction and dehydration to generate racemic ambroxol. Harmonic acid is an important intermediate in the synthesis of ambroxol. European patent EP3060546B1 discloses a method using 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)butanal as a raw material, which reacts with malonic acid to generate β-monocyclic high-harmonic acid. Compared with patent EP0550889B1, this synthetic process significantly shortens the process route.

[0005] 2-Methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)butanal, an important raw material for the production of hyaluronic acid, is prepared by selectively hydrogenating 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal (an α-β-unsaturated aldehyde). While supported Pd / C catalysts are commonly used for the selective hydrogenation of C=C in α-β-unsaturated aldehydes, the hydrogenation process is challenging. The Pd / C catalyst contains numerous micropores, and the reactant 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal diffuses slowly and faces high resistance within these micropores. This leads to blockage of the activated carbon channels during reactant-product exchange, resulting in reduced catalyst activity, difficulty in catalyst separation, and inability to be reused.

[0006] Given the aforementioned problems with existing supported Pd / C catalysts, there is a need to provide a catalyst and its preparation method for application in the selective hydrogenation reaction of 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal, which is expected to exhibit good catalytic performance, and be easy to separate and reusable. Summary of the Invention

[0007] The main objective of this invention is to provide a catalyst, its preparation method, and its application, in order to solve the problems in the prior art where the catalyst has low or no catalytic activity in the catalytic hydrogenation reaction of 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal, or where the catalyst is difficult to separate from the reaction system for reuse.

[0008] To achieve the above objectives, according to one aspect of the present invention, a catalyst is provided, the catalyst comprising a support and an active component loaded on the support by chemical bonding; wherein the support is aminated polystyrene; and the active component is palladium metal.

[0009] Furthermore, the carrier is prepared by the following method: a raw material solution including styrene monomer, crosslinking agent, amino functionalizing agent and water is prepared, and an initiator is added to the raw material solution to carry out emulsion polymerization reaction to obtain the carrier.

[0010] Further, the amino-functionalizing agent is selected from one or more of allylamine, diallylamine, triallylamine or oleylamine; the crosslinking agent is preferably triallylamine and / or divinylbenzene; more preferably divinylbenzene; the initiator is preferably an inorganic peroxide; more preferably one or more of ammonium persulfate, potassium persulfate or sodium persulfate; the emulsion polymerization reaction is preferably carried out in an inert atmosphere, and the inert gas of the inert atmosphere is preferably selected from one or more of nitrogen, argon or helium, more preferably nitrogen; the temperature of the emulsion polymerization reaction is preferably 80~85℃, and the reaction time is 6~10h; the weight ratio of water to crosslinking agent, amino-functionalizing agent, styrene monomer and initiator is preferably 1:(0.006~0.01):(0.005~0.015):(0.10~0.25):(0.00075~0.00095).

[0011] Furthermore, in the catalyst, the weight ratio of the support to the active component is 1:(0.010~0.050).

[0012] Furthermore, the active component is in the form of particles; more preferably, the D50 particle size of the active component is 4.3~6.2 nm; more preferably, the shape of the support is spherical or near-spherical; more preferably, the average radius of the support is 810.2~920.3 nm.

[0013] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a catalyst is provided, the method comprising: coordinating a support with a palladium source, then adding a reducing agent to the reaction system to carry out a reduction reaction, thereby obtaining a catalyst.

[0014] Further, the palladium source is preferably selected from one or more of palladium chloride, palladium acetate, palladium nitrate or palladium sulfate, and more preferably palladium acetate; the reducing agent is preferably selected from one or more of organic alkali metal salts, and more preferably sodium borohydride, potassium borohydride or sodium formate, and more preferably sodium formate.

[0015] Furthermore, the preferred temperature for the coordination reaction is 20~30℃, and the preferred reaction time is 4~18h; the preferred temperature for the reduction reaction is 80~85℃, and the preferred reaction time is 1~3h.

[0016] Furthermore, after the reduction reaction, the preparation method also includes sequentially filtering, washing and drying the reduction product; preferably, the drying is carried out in a vacuum environment; more preferably, the drying temperature is 40~60℃ and the drying time is 4~8h; preferably, the washing agent is selected from one or more of water, ethanol, dichloromethane or acetone.

[0017] According to another aspect of the present invention, the above-described catalyst, or the catalyst prepared by the above-described catalyst preparation method, is provided for use in the catalytic hydrogenation reaction of 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal.

[0018] The catalyst prepared by this invention not only exhibits excellent catalytic performance in the hydrogenation reaction of (2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal, but is also easy to separate and reuse, and can maintain excellent catalytic performance even during repeated applications. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A TEM image (magnification of 65,000x) of the catalyst prepared according to Example 1 of the present invention is shown. Figure 2 A TEM image (magnification 39,000x) of the catalyst support prepared according to Example 1 of the present invention is shown. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] As described in the background section of this invention, existing catalysts in the prior art suffer from problems such as low catalytic activity or difficulty in separating the catalyst from the reaction system for reuse in the catalytic hydrogenation reaction of 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal. To address this problem, this invention provides a catalyst comprising a support and an active component chemically bonded to the support; wherein the support is aminated polystyrene; and the active component is palladium.

[0022] In the catalyst used in this invention, the catalyst support is amino-modified polystyrene and the active component is palladium metal. In the process of preparing 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal from (2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal by hydrogenation, this catalyst not only has excellent catalytic effect, but is also easy to separate for reuse, and can still maintain excellent catalytic performance during repeated applications.

[0023] In particular, this invention creatively employs aminated polystyrene as a catalyst support. Firstly, the presence of amino functional groups on the polystyrene surface allows the palladium active component to be firmly and uniformly loaded onto the catalyst support surface via coordination bonds, thereby improving the catalyst's activity and stability, and consequently enhancing its catalytic performance in the catalytic reaction, specifically manifested as higher conversion and selectivity. Secondly, the aforementioned catalytic reaction is carried out in an alkaline aqueous solvent. Since the raw materials (2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal and the product 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)butanal) are both organic compounds insoluble in alkaline aqueous solvents; simultaneously, the catalyst with an aminated polystyrene support used in this invention is hydrophobic and also insoluble in the aforementioned alkaline aqueous solvent. Therefore, the entire reaction system forms a microemulsion system under stirring. Moreover, according to the principle of "like dissolves like," the catalyst and reactants can further and fully contact each other in the above system, improving catalytic activity. Based on this... Since hydrogen is more soluble in organic phases than in aqueous phases, it can further promote the smooth progress of the catalytic reaction and improve reactant conversion and product yield in the above-mentioned hydrogenation catalysis process. Thirdly, compared to conventional Pd / C catalysts which contain a large number of micropores, reactants tend to diffuse slowly and encounter high resistance within these micropores during catalysis, leading to blockage of activated carbon channels during reactant-product exchange, making catalyst separation difficult and unusable. In contrast, the aminated polystyrene prepared in this invention, as a catalyst support without surface pores, makes product separation from the catalyst surface easier and allows for reuse.

[0024] In a preferred embodiment, the carrier is prepared by the following method: a raw material solution comprising styrene monomer, crosslinking agent, amino functionalizing agent and water is prepared, and an initiator is added to the raw material solution to carry out a batch emulsion polymerization reaction to obtain the carrier.

[0025] Those skilled in the art can prepare the support using the following method: First, a feedstock solution comprising styrene monomer, crosslinking agent, amino-functionalizing reagent, and water is prepared. Then, an initiator is added to the feedstock solution to carry out a batch emulsion polymerization reaction, finally obtaining the support. The above-mentioned method for preparing the support has the advantages of mild reaction conditions, convenient operation, and simple process, and has broad prospects for industrial application. Furthermore, the catalyst support prepared by this method can maintain a high dispersion of the active component palladium metal, while also possessing strong mechanical strength, thereby further improving the catalytic performance of the catalyst.

[0026] In a preferred embodiment, the amino functionalizing agent is selected from one or more of allylamine, diallylamine, triallylamine, or oleylamine; thereby giving the surface of the prepared amino-functionalized polystyrene abundant amino functional groups, further improving the activity and stability of the catalyst; in order to further improve the degree of crosslinking of the amino-functionalized polystyrene and further improve its mechanical properties, the crosslinking agent is preferably triallylamine and / or divinylbenzene; more preferably divinylbenzene.

[0027] To further improve the polymerization reaction of aminated polystyrene and increase its degree of polymerization, the initiator is preferably an inorganic peroxide; more preferably, it is one or more of ammonium persulfate, potassium persulfate, or sodium persulfate. To further promote the polymerization reaction and improve the thermal stability of the polymer, the emulsion polymerization reaction is preferably carried out in an inert atmosphere, and more preferably, the inert gas in the inert atmosphere is one or more of nitrogen, argon, or helium, more preferably nitrogen. The weight ratio of water to crosslinking agent, aminofunctionalizing agent, styrene monomer, and initiator is preferably 1:(0.006~0.01):(0.005~0.015):(0.10~0.25):(0.075~0.095), which can further improve the strength and thermal stability of aminated polystyrene, and thus further improve the catalytic performance of the catalyst.

[0028] To further improve the activity and stability of the catalyst, thereby enhancing its catalytic performance and increasing its conversion and selectivity in the catalytic hydrogenation of 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal to prepare 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)butanal, the preferred weight ratio of support to active component is 1:(0.010~0.050).

[0029] In a preferred embodiment, the support is spherical or near-spherical in shape, and more preferably, the average radius of the support is 810.2~920.3 nm. This allows the palladium active component to be more firmly and uniformly loaded onto the catalyst support surface through coordination bonds, thereby improving the catalyst's activity and stability, and thus enhancing its catalytic performance in the catalytic reaction. More preferably, the active component is particulate, and more preferably, the D50 particle size of the active component is 4.3~6.2 nm. This further promotes easier contact between the reactants and the palladium active centers on the catalyst support surface, thus better facilitating the catalytic reaction and resulting in excellent catalytic performance.

[0030] Another aspect of the present invention provides a method for preparing a catalyst, the method comprising: coordinating a support with a palladium source, then adding a reducing agent to the reaction system to carry out a reduction reaction, thereby obtaining a catalyst.

[0031] Those skilled in the art can prepare catalysts using the following method: first, the support undergoes a coordination reaction with a palladium source; then, a reducing agent is added to the reaction system for a reduction reaction, ultimately yielding the catalyst. The above-described method for preparing the support has the advantages of mild conditions, convenient operation, and simple process, making it suitable for large-scale production and possessing broad prospects for industrial application. Furthermore, the catalyst prepared using this method not only exhibits excellent catalytic performance but is also easily separated and reusable.

[0032] In a preferred embodiment, the weight ratio of the support to the palladium source is 1:(0.01~0.1), which further promotes the enrichment of more amino functional groups on the polystyrene surface. This allows the active palladium component to be firmly and uniformly loaded onto the catalyst support surface through coordination bonds, thereby improving the catalyst's activity and stability, and thus enhancing its catalytic performance in catalytic reactions. Preferably, the palladium source is selected from one or more of palladium chloride, palladium acetate, palladium nitrate, or palladium sulfate, and more preferably palladium acetate. To further promote the complete reduction of divalent palladium ions, the reducing agent is preferably selected from organometallic salts, more preferably one or more of sodium borohydride, potassium borohydride, or sodium formate, and more preferably sodium formate. The concentration of the reducing agent is preferably 0.5~1 mol / L, thereby further improving the catalyst's catalytic activity.

[0033] To further promote the full progress of the coordination reaction, improve the activity and stability of the active component palladium on the catalyst support surface, and thus improve the catalytic performance of the catalyst, the preferred temperature for the coordination reaction is 20~30℃ and the preferred reaction time is 4~18h; to further promote the full reduction reaction, the preferred temperature for the reduction reaction is 80~85℃ and the preferred reaction time is 1~3h.

[0034] In a preferred embodiment, after the reduction reaction, the preparation method further includes filtering, washing and drying the reduction product in sequence. The drying is carried out in a vacuum environment, which can further remove impurities on the surface of the reduction product and improve the catalytic performance of the catalyst. More preferably, the drying temperature is 40~60℃ and the drying time is 4~8h. In order to further avoid the influence of impurities on the surface of the reduction product on the catalytic performance, the washing agent is preferably selected from one or more of water, ethanol, dichloromethane or acetone.

[0035] Another aspect of the present invention provides the application of a catalyst in the catalytic hydrogenation reaction of 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal. As mentioned above, the catalyst has excellent catalytic activity stability, exhibits high conversion rate and selectivity, and is not only easy to separate but also reusable.

[0036] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0037] Example 1

[0038] 200 g of deionized water, 20 g of styrene, 1.22 g of divinylbenzene, and 1 g of triallylamine were added to a 500 mL three-necked flask. Nitrogen gas was bubbled through the flask to purge air from the solution, and the mixture was sonicated for 1 h. Under nitrogen protection, 0.15 g of ammonium persulfate was added. The weight ratio of water to crosslinking agent, amino-functionalizing reagent, styrene monomer, and initiator was 1:0.0061:0.005:0.1:0.00075. The mixture was stirred at 80 °C for 7 h. After filtration, the mixture was vacuum dried at 50 °C for 12 h to obtain amino-functionalized polystyrene carrier A.

[0039] 1g of the amino-functionalized polystyrene support A obtained above was dispersed in 50g of anhydrous ethanol and sonicated for 0.5h to obtain a support dispersion system. Then, 0.0532g of palladium acetate was dissolved in 26g of acetonitrile to obtain a palladium acetate solution. The weight ratio of support to palladium acetate was 1:0.0532. This palladium acetate solution was slowly added dropwise to the support dispersion system, and the reaction was carried out at 25℃ with stirring for 12h. As the reaction proceeded, the solution color changed from pale yellow to grayish-black, indicating that palladium acetate had undergone a coordination reaction with the support. Then, under nitrogen protection, the temperature was raised to 80℃. 0.0312g of sodium formate dissolved in 10g of water in another beaker was slowly added dropwise to the above mixed solution. After stirring for another 1h, the solution was filtered, washed with deionized water and ethanol, and dried under vacuum at 50℃ for 6h to obtain the catalyst, denoted as Cat.A, which was then subjected to catalytic performance testing.

[0040] Figure 1 A TEM image of the catalyst is shown (magnification 65,000). Figure 2 A TEM image of the catalyst support is shown (magnification 39,000x).

[0041] Example 2

[0042] 200g of deionized water, 20g of styrene, 1.22g of divinylbenzene, and 2.33g of triallylamine were added to a 500mL three-necked flask. Nitrogen gas was bubbled through the flask to purge air from the solution, and the mixture was sonicated for 1 hour. Under nitrogen protection, 0.15g of ammonium persulfate was added. The weight ratio of water to crosslinking agent, amino-functionalizing reagent, styrene monomer, and initiator was 1:0.0061:0.005:0.1:0.00075. The mixture was stirred at 80℃ for 4 hours. After filtration, the mixture was vacuum dried at 50℃ for 12 hours to obtain amino-functionalized polystyrene carrier B.

[0043] 1g of the amino-functionalized polystyrene support B obtained above was dispersed in 50g of anhydrous ethanol and sonicated for 0.5h to obtain a support dispersion system. Then, 0.0532g of palladium acetate was dissolved in 26g of acetonitrile to obtain a palladium acetate solution. The weight ratio of support to palladium acetate was 1:0.0532. This palladium acetate solution was slowly added dropwise to the support dispersion system, and the reaction was carried out at 25℃ with stirring for 12h. As the reaction proceeded, the solution color changed from pale yellow to grayish-black, indicating that palladium acetate had undergone a coordination reaction with the support. Then, under nitrogen protection, the temperature was raised to 80℃. 0.0312g of sodium formate dissolved in 10g of water in another beaker was slowly added dropwise to the above mixed solution. The reaction was continued with stirring for 1h. After filtration, washing with deionized water and anhydrous ethanol, and drying under vacuum at 50℃ for 6h, the catalyst, denoted as Cat.B, was obtained and its catalytic performance was tested.

[0044] Example 3

[0045] 200g of deionized water, 20g of styrene, 1.22g of divinylbenzene, and 2.33g of triallylamine were added to a 500mL three-necked flask. Nitrogen gas was bubbled through the flask to purge air from the solution, and the mixture was sonicated for 1 hour. Under nitrogen protection, 0.15g of ammonium persulfate was added. The weight ratio of water to crosslinking agent, amino-functionalizing reagent, styrene monomer, and initiator was 1:0.0061:0.005:0.1:0.00075. The mixture was stirred at 80℃ for 4 hours. After filtration, the mixture was vacuum dried at 50℃ for 12 hours to obtain amino-functionalized polystyrene carrier B.

[0046] 1 g of amino-functionalized polystyrene support B was dispersed in 50 g of anhydrous ethanol and sonicated for 0.5 h to obtain a support dispersion system. Then, 0.1064 g of palladium acetate was dissolved in 52 g of acetonitrile to obtain a palladium acetate solution. The weight ratio of support to palladium acetate was 1:0.1064. This palladium acetate solution was slowly added dropwise to the support dispersion system, and the mixture was stirred at 25 °C for 12 h. As the reaction proceeded, the solution color changed from pale yellow to grayish-black, indicating that palladium acetate had undergone a coordination reaction with the support. Then, under nitrogen protection, the temperature was raised to 80 °C. 0.0625 g of sodium formate dissolved in 10 g of water was taken from another beaker and slowly added dropwise to the above mixed solution. The mixture was stirred for another h, and then filtered, washed with deionized water and anhydrous ethanol, and dried under vacuum at 50 °C for 6 h to obtain the catalyst, denoted as Cat.C. Its catalytic performance was then tested.

[0047] Example 4

[0048] The difference from Example 3 is that the catalyst used was Cat.C, which was cyclically catalyzed 5 times before the catalytic performance was tested for the 6th time.

[0049] Example 5

[0050] The difference from Example 1 is that the catalyst used was Cat.A, which was cyclically catalyzed 5 times before the catalytic performance was tested for the 6th time.

[0051] Example 6

[0052] The difference from Example 2 is that the catalyst used was Cat.B, which was cyclically catalyzed 5 times before the catalytic performance was tested for the 6th time.

[0053] Example 7

[0054] The difference from Example 1 is that the amino-functionalizing reagent used is allylamine, and the resulting catalyst is denoted as Cat.D.

[0055] Example 8

[0056] The difference from Example 1 is that the amino-functionalizing reagent used is diallylamine, and the resulting catalyst is denoted as Cat.E.

[0057] Example 9

[0058] The difference from Example 1 is that the amino functionalizing agent used is oleylamine, and the resulting catalyst is denoted as Cat.F.

[0059] Comparative Example 1

[0060] Pd / C catalyst.

[0061] Comparative Example 2

[0062] The difference from Example 1 is that no amino-functionalizing agent is added, and the catalyst is designated as Cat.G.

[0063] Catalytic performance test: 1 g of the catalyst prepared in Examples 1 to 3, 7 to 9, Comparative Examples 1 and 2, sodium hydroxide solution, and 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal were sequentially added to a 500 mL high-pressure reactor equipped with a magnetic stirrer and sealed. The air inside the reactor was replaced with low-pressure hydrogen gas. The initial pressure was set to 2.5 MPa, the reaction temperature to 75 °C, and the reaction time to 5 h with a stirring speed of 1000 rpm. After the reaction was completed, the reactor temperature was allowed to drop to room temperature, the pressure was released, the mixture was filtered, and washed with water to generate 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)butenal. The conversion rate and selectivity of 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)butenal were determined by gas chromatography.

[0064] The physical properties of the catalysts prepared in the examples are shown in Table 1.

[0065] Table 1

[0066] The catalytic performance test results of the examples and comparative examples are shown in Table 2.

[0067] Table 2

[0068] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: The test data from Examples 1, 2, and 3 and Comparative Example 1 show that when the catalyst of the present invention is used for catalytic reaction, the conversion rate of reactants and the selectivity of products are high, and the catalytic performance is superior; while when conventional Pd / C is used as catalyst, the catalytic effect is poor and the conversion rate is significantly reduced.

[0069] The test results of Examples 1, 7, 8, 9 and Comparative Example 2 show that when the catalyst of the present invention is used, especially in the catalyst preparation process, the amino functionalizing agent is selected from one or more of allylamine, diallylamine, triallylamine or oleylamine, and the technical effect of the present invention can be achieved. When applied to catalytic reactions, the conversion rate of reactants and the selectivity of products are high, and the catalytic performance is better. However, the catalyst prepared without the addition of amino functionalizing agent has poor effect.

[0070] The test results of Examples 4, 5, and 6 show that when the catalyst of the present invention is used for catalytic reaction, not only is the conversion rate of reactants and the selectivity of products high, but the catalytic performance is still good after 5 cycles, and it is easy to separate and reuse.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A catalyst, characterized in that, The catalyst comprises a support and an active component loaded on the support by chemical bonding; wherein... The carrier is aminated polystyrene; The active component is palladium metal; The carrier was prepared by the following method: A raw material solution comprising styrene monomer, crosslinking agent, amino functionalizing agent and water is prepared, and an initiator is added to the raw material solution to carry out an emulsion polymerization reaction to obtain the carrier; The amino-functionalizing agent is selected from one or more of allylamine, diallylamine, triallylamine, or oleylamine.

2. The catalyst according to claim 1, characterized in that, The crosslinking agent is triallylamine and / or divinylbenzene.

3. The catalyst according to claim 2, characterized in that, The crosslinking agent is divinylbenzene.

4. The catalyst according to claim 1, characterized in that, The initiator is an inorganic peroxide.

5. The catalyst according to claim 4, characterized in that, The initiator is one or more of ammonium persulfate, potassium persulfate, or sodium persulfate.

6. The catalyst according to claim 1, characterized in that, The emulsion polymerization reaction is carried out under an inert atmosphere.

7. The catalyst according to claim 6, characterized in that, The inert gas in the inert atmosphere is selected from one or more of nitrogen, argon, or helium.

8. The catalyst according to claim 6, characterized in that, The inert gas in the inert atmosphere is nitrogen.

9. The catalyst according to claim 1, characterized in that, The emulsion polymerization reaction is carried out at a temperature of 80-85°C for 6-10 hours.

10. The catalyst according to claim 1, characterized in that, The weight ratio of water to the crosslinking agent, the amino-functionalized reagent, the styrene monomer, and the initiator is 1:(0.006~0.01):(0.005~0.015):(0.10~0.25):(0.00075~0.00095).

11. The catalyst according to claim 1, characterized in that, In the catalyst, the weight ratio of the support to the active component is 1:(0.010~0.050).

12. The catalyst according to claim 1, characterized in that, The active component is in the form of particles.

13. The catalyst according to claim 12, characterized in that, The D50 particle size of the active component is 4.3~6.2 nm.

14. The catalyst according to claim 1, characterized in that, The carrier is spherical or near-spherical in shape.

15. The catalyst according to claim 14, characterized in that, The average radius of the carrier is 810.2~920.3 nm.

16. A method for preparing a catalyst according to any one of claims 1 to 15, characterized in that, The preparation method includes: After the support and palladium source undergo a coordination reaction, a reducing agent is added to the reaction system to carry out a reduction reaction, thereby obtaining the catalyst.

17. The method for preparing the catalyst according to claim 16, characterized in that, The palladium source is selected from one or more of palladium chloride, palladium acetate, palladium nitrate, or palladium sulfate.

18. The method for preparing the catalyst according to claim 17, characterized in that, The palladium source is palladium acetate.

19. The method for preparing the catalyst according to claim 16, characterized in that, The reducing agent is selected from organic alkali metal salts.

20. The method for preparing the catalyst according to claim 19, characterized in that, The reducing agent is one or more of sodium borohydride, potassium borohydride, or sodium formate.

21. The method for preparing the catalyst according to claim 20, characterized in that, The reducing agent is sodium formate.

22. The method for preparing the catalyst according to claim 16, characterized in that, The coordination reaction is carried out at a temperature of 20-30°C for 4-18 hours.

23. The method for preparing the catalyst according to claim 16, characterized in that, The reduction reaction is carried out at a temperature of 80-85°C for 1-3 hours.

24. The method for preparing the catalyst according to claim 16, characterized in that, Following the reduction reaction, the preparation method further includes sequentially filtering, washing, and drying the reduction product.

25. The method for preparing the catalyst according to claim 24, characterized in that, The drying process is carried out under vacuum.

26. The method for preparing the catalyst according to claim 24, characterized in that, The drying process is carried out at a temperature of 40-60°C for 4-8 hours.

27. The method for preparing the catalyst according to claim 24, characterized in that, The detergent used for washing is selected from one or more of water, ethanol, dichloromethane, or acetone.

28. The use of a catalyst according to any one of claims 1 to 15, or a catalyst prepared by the method of any one of claims 16 to 27, in the catalytic hydrogenation of 2-methyl-4-(2,2,6-trimethyl-1-cyclohexenyl)-2-butenal.

Images