Catalyst as well as preparation method and application thereof

Abstract

The invention relates to the field of catalysts, and discloses a catalyst for preparing dimethyl 1, 4-cyclohexanedicarboxylate through dimethyl terephthalate hydrogenation as well as a preparation method and application of the catalyst. According to the catalyst, gamma-aluminum oxide serves as a carrier, five-element high-entropy alloy particles are loaded, five elements including Co, Ni, Zr, Nb and Pd are contained, and the usage amount of precious metal is effectively reduced. The catalyst is simple in preparation method, mild in reaction condition, high in dimethyl terephthalate conversion rate, good in 1, 4-cyclohexanedicarboxylic acid dimethyl ester selectivity and suitable for industrial production and use. The catalyst provided by the invention has high catalytic activity, strong stability and high selectivity, significantly reduces the production cost, and has significant economic benefits and industrial application values.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a catalyst for preparing dimethyl 1,4-cyclohexanedicarboxylate by hydrogenating dimethyl terephthalate, and a preparation method and application thereof. Background Art

[0002] Dimethyl 1,4-cyclohexanedicarboxylate (DMCD) is an extremely important organic chemical raw material. It can not only be used for polymer modification materials to improve the performance of polymers, but also is an important intermediate for the production of 1,4-cyclohexanedimethanol (CHDM). In addition, it can be used to produce other chemical products such as alkyd resins and plasticizers. It can be widely used in the manufacture of coating resins, polyester resins, alkyd resins and plasticizers to meet the needs of different industrial fields. Therefore, it plays an important role in the industrial field.

[0003] Palladium metal is often used as a catalyst for DMCD. The literature (Zhang F, Chen J, Chen P. Pd Nanoparticles Supported on Hydrotalcite-modified Porous Alumina Spheres as Selective Hydrogenation Catalyst [J]. AIChE Journal, 2012 (6): 58.) reported a supported Pd / HTC-Al2O3 catalyst with excellent conversion rate and selectivity. The required pressure range for the reaction is 20-40 MPa, and the reaction temperature range is 180-250°C. The reaction conditions are relatively harsh and will generate huge economic costs and resource consumption in industrial production. Literature (Li XF, Sun ZY, Chen JL, Zhu Y, Zhang F Z. One-pot conversion of dimethyl terephthalate into 1,4-cyclohexanedimethanol with supported trimetallic PdPtSn catalysts. Ind. Eng. Chem. Res. 2014, 53 (2): 619-625.) reports a modification treatment of catalyst Pd / Al2O3 with two metals Pt and Sn. The obtained product can convert DMT into DMCD in an environment of 100° C. and 2 MPa. However, the disadvantages are that there are many side reaction products and the cost of catalyst raw materials is high.

[0004] The literature (Chen JL, Liu X, Zhang F Z. Composition regulation of bimetallicRuPd catalysts supported on porous alumina spheres for selective hydrogenation. Chem. Eng. J. 2015, 259: 43-52) used the impregnation method to prepare a low-loaded RuCu bimetallic catalyst. At 180°C and 8MPa, the selectivity of DMCD and the conversion rate of MDT were 96.2% and 88.5%, respectively. However, the preparation method of this catalyst is relatively complicated.

[0005] In summary, Pd-based catalysts are expensive and require harsh conditions of high temperature and high pressure to achieve high selectivity and conversion rate. Therefore, this patent provides a catalyst preparation method with a simple preparation method and low cost. The catalyst can significantly reduce the amount of Pd used and has excellent conversion rate and selectivity under mild reaction conditions. It can be used for the hydrogenation of dimethyl terephthalate to produce dimethyl 1,4-cyclohexanedicarboxylate. Summary of the invention

[0006] One of the technical problems to be solved by the present invention is to provide a low-cost catalyst for hydrogenation of dimethyl terephthalate to solve the problem of excessively high production and use costs of existing catalysts.

[0007] The second technical problem to be solved by the present invention is to provide a low-cost preparation method for a dimethyl terephthalate hydrogenation catalyst corresponding to the first problem to be solved. The method can be used to produce a catalyst for the hydrogenation of dimethyl terephthalate, overcoming the shortcomings of the existing catalyst preparation process being cumbersome, and having low conversion rate and selectivity.

[0008] The third technical problem to be solved by the present invention is to provide a catalyst for hydrogenation of dimethyl terephthalate which can be used under mild conditions, corresponding to the first problem to be solved, thereby overcoming the disadvantage of harsh reaction conditions.

[0009] In order to solve one of the above technical problems, the technical solution adopted by the present invention is as follows: a catalyst for preparing dimethyl 1,4-cyclohexanedicarboxylate by hydrogenation of dimethyl terephthalate, comprising γ-alumina as a carrier, and a five-element high entropy alloy uniformly distributed on the carrier. Wherein, the five-element high entropy alloy is calcined to contain five elements of Co, Ni, Zr, Nb, and Pd, and the doped metals are calculated by mass percentage, wherein the doping amount of Co is 0.1-25wt%, the doping amount of Ni is 0.1-30wt%, the doping amount of Zr is 30-80wt%, the doping amount of Nb is 10-35wt%, the doping amount of Pd is 1-5wt%, and the sum of the five metal elements is 100wt%.

[0010] Preferably, the doping amount of Co in the catalyst is 8.5-23.5wt%, the doping amount of Ni is 12.5-26.3wt%, the doping amount of Zr is 35.8-64.1wt%, the doping amount of Nb is 13.3-31.9wt%, and the doping amount of Pd is 1.2-4.6wt%.

[0011] In order to solve the second technical problem mentioned above, the technical solution adopted by the present invention is as follows: the preparation method of the catalyst for preparing dimethyl 1,4-cyclohexanedicarboxylate by hydrogenating dimethyl terephthalate comprises the following steps:

[0012] (a) taking a certain amount of pseudo-boehmite and calcining it at a constant temperature in a muffle furnace to obtain a carrier γ-alumina, which is used as a precursor;

[0013] (b) Dissolve metal salts of cobalt salt, zirconium salt, nickel salt, niobium salt and palladium salt in 50 ml of alcohol solution and mix them evenly. After adding the precursor to the metal salt solution, add 15 ml of oleylamine to the solution and react in an 80°C oil bath for 10 hours. After the reaction, add 100 ml of deionized water and transfer to a reactor and react at 150°C for 12 hours. After cooling, filter the product in the reactor and dry it at 120°C. After it is completely dried, calcine it in a N2 environment at a temperature of 500-900°C for 1-5 hours.

[0014] Preferably, in step (1), the amount of pseudo-boehmite is 15-35 g; the calcination temperature is 400-750° C., and the calcination time is 3-5 h; the heating rate is 2-5° C. / min, and the calcination time is 2-5 h.

[0015] Preferably, in step (2), the cobalt salt is one or more of cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt acetate, cobalt carbonate, and cobalt oxalate, and the doping amount of cobalt is 0.1-25wt%, and cobalt acetate is further preferred, and the doping amount is 8.5-23.5wt%; the nickel salt is one or more of nickel chloride, nickel sulfate, nickel nitrate, nickel acetate, nickel carbonate, and nickel oxalate, and the doping amount of nickel is 0.1-30wt%, and nickel acetate is further preferred, and the doping amount is 12.5-26.3wt%; the zirconium salt is one or more of zirconium chloride, zirconium sulfate, zirconium nitrate, and zirconium acetate, and the doping amount of zirconium is 30-80wt%, and chloride is further preferred. The zirconium salt has a doping amount of 35.8-64.1wt%; the niobium salt is one or more of niobium chloride, niobium sulfate, and niobium nitrate, and the doping amount of niobium is 10-35wt%, and niobium chloride is further preferred, and the doping amount is 13.3-31.9wt%; the palladium salt is one or more of palladium chloride, palladium nitrate, and palladium sulfate, and the doping amount of palladium is 1-5wt%, and palladium chloride is further preferred, and the doping amount is 1.2-4.6wt%; the alcohol is one of anhydrous ethanol, isopropanol, and methanol; during the N2 roasting process, the heating rate is 3-7℃ / min, the roasting temperature is 550-800℃, and the roasting time is 2-5h.

[0016] In order to solve the third technical problem mentioned above, the technical solution adopted by the present invention is as follows: a method for producing dimethyl 1,4-cyclohexanedicarboxylate, using a catalyst for solving one of the technical problems, adding a catalyst and dimethyl terephthalate in a mass ratio of (1-3):30, and a reaction solvent cyclohexane to a reactor, filling hydrogen to replace the air in the reactor, and then pressurizing to 0.5-5MPa, reacting at 120-250°C for 3h, and reacting to generate a product containing dimethyl 1,4-cyclohexanedicarboxylate, the conversion rate of dimethyl terephthalate is 83.29-99.96%, and the selectivity of dimethyl 1,4-cyclohexanedicarboxylate is 84.24-99.99%.

[0017] The five-element high entropy alloy catalyst supported by γ-alumina prepared by the present invention uses γ-alumina with large specific surface area and large pore size as a carrier, and the high entropy alloy selected by the catalyst is an active site, which is composed of five metals of Co, Ni, Zr, Ni, and Pd. Due to its homogeneity and microscopic uniformity, its microstructure is more stable and not prone to phase change and deactivation. And compared with traditional precious metal catalysts, the precious metal content in the catalyst is low, which effectively reduces the overall cost of the catalytic process. At the same time, the carrier of this catalyst is γ-alumina, and the interaction and synergistic reaction between this carrier and the active site effectively inhibit the migration and aggregation problems during the formation of the high entropy alloy, improve the activity of the catalyst, and overcome the problems of cumbersome and high cost of preparing the catalyst in the existing production technology. The five-element high entropy alloy catalyst supported by γ-alumina can be used in the production field of preparing dimethyl terephthalate by hydrogenation of dimethyl terephthalate to improve the conversion rate and the selectivity of dimethyl 1,4-cyclohexanedicarboxylate.

[0018] The catalyst provided by the present invention and its preparation method and application have the following significant technical effects:

[0019] (1) The catalyst provided by the present invention uses γ-alumina as a carrier and is loaded with five-element high entropy alloy particles. The catalyst has excellent catalytic performance and can achieve efficient hydrogenation conversion of dimethyl terephthalate to produce 1,4-cyclohexanedicarboxylic acid dimethyl ester under mild conditions.

[0020] (2) The catalyst preparation method provided by the present invention is simple, easy to operate, and easy to industrialize. By adjusting the type and doping amount of the metal salt, catalysts with different catalytic properties can be prepared to meet the needs of different industrial fields.

[0021] (3) The catalyst provided by the present invention has a high conversion rate and selectivity in the reaction of hydrogenating dimethyl terephthalate to prepare dimethyl 1,4-cyclohexanedicarboxylate, and the reaction conditions are mild, without the need for high temperature and high pressure, thereby reducing production costs and resource consumption.

[0022] (4) The catalyst provided by the present invention has a low content of precious metals, which effectively reduces the overall cost of the catalytic process and has significant economic benefits. DETAILED DESCRIPTION

[0023] The present invention is described below by means of specific embodiments, but the present invention is not limited thereto.

[0024] The preparation methods and conditions used in the following examples are conventional methods unless otherwise specified; the reagents and materials used in the following examples are commercially available unless otherwise specified.

[0025] 1. Catalyst

[0026] The catalyst provided by the present invention uses γ-alumina as a carrier and is loaded with five-element high entropy alloy particles containing five elements: Co, Ni, Zr, Nb, and Pd. The doping amount (in mass percentage) of each metal element in the catalyst is as follows:

[0027] The doping amount of Co is 0.1-25wt%,

[0028] The doping amount of Ni is 0.1-30wt%,

[0029] The doping amount of Zr is 30-80wt%,

[0030] The doping amount of Nb is 10-35wt%,

[0031] The doping amount of Pd is 1-5wt%.

[0032] As a preferred embodiment, the doping amount (in mass percentage) of each metal element in the catalyst can be further adjusted as follows:

[0033] The doping amount of Co is 8.5-23.5wt%,

[0034] The doping amount of Ni is 12.5-26.3wt%,

[0035] The doping amount of Zr is 35.8-64.1wt%,

[0036] The doping amount of Nb is 13.3-31.9wt%,

[0037] The doping amount of Pd is 1.2-4.6wt%.

[0038] And the sum of the five metal elements should be 100wt%.

[0039] 2. Preparation method of catalyst

[0040] The catalyst preparation method provided by the present invention comprises the following steps:

[0041] Step (a): Preparation of γ-alumina carrier

[0042] Take a certain amount of pseudo-boehmite and calcine it at a constant temperature in a muffle furnace to obtain a carrier γ-alumina as a precursor. The calcination temperature range is 300-900°C, the calcination time range is 1-6h, and the heating rate range is 1-6°C / min. Preferably, the calcination temperature range is 400-750°C, the calcination time range is 3-5h, and the heating rate range is 2-5°C / min. The amount of pseudo-boehmite used ranges from 15-35g.

[0043] Step (b): Preparation of five-element high entropy alloy catalyst

[0044] Dissolve the metal salts of cobalt salt, zirconium salt, nickel salt, niobium salt and palladium salt in an alcohol solution and mix them evenly. After adding the precursor, add oleylamine to the solution and react in an 80°C oil bath for 10 hours. After the reaction is completed, add deionized water and transfer to a reactor to react at 100-180°C for 12 hours. After cooling, filter the product in the reactor and dry it, then calcine it in a N2 atmosphere to obtain a catalyst.

[0045] Specifically, the volume of the alcohol solution is 50 ml, the amount of oleylamine added is 15 ml, and the amount of deionized water added is 100 ml. The drying temperature is preferably 120° C., the calcination temperature range is 500-900° C., the calcination time range is 1-5 h, and the heating rate range is 1-6° C. / min. Preferably, the calcination temperature range is 550-800° C., the calcination time range is 2-5 h, and the heating rate range is 3-7° C. / min.

[0046] The cobalt salt may be one or more of cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt acetate, cobalt carbonate, and cobalt oxalate; the nickel salt may be one or more of nickel chloride, nickel sulfate, nickel nitrate, nickel acetate, nickel carbonate, and nickel oxalate; the zirconium salt may be one or more of zirconium chloride, zirconium sulfate, zirconium nitrate, and zirconium acetate; the niobium salt may be one or more of niobium chloride, niobium sulfate, and niobium nitrate; the palladium salt may be one or more of palladium chloride, palladium nitrate, palladium sulfate, and sodium tetrachloropalladate.

[0047] As a preferred embodiment, the cobalt salt is cobalt acetate, the nickel salt is nickel acetate, the zirconium salt is zirconium chloride, the niobium salt is niobium chloride, and the palladium salt is palladium chloride.

[0048] 3. Application of Catalyst

[0049] The catalyst provided by the present invention exhibits excellent catalytic performance in the reaction of preparing dimethyl 1,4-cyclohexanedicarboxylate by hydrogenation of dimethyl terephthalate. The specific application method is as follows:

[0050] Add dimethyl terephthalate, catalyst and reaction solvent into the reactor, fill with hydrogen to replace the air in the reactor, pressurize to 0.5-5MPa, and react at 120-250°C for 3h. The mass ratio of catalyst to dimethyl terephthalate is preferably 1:(3-30). After the reaction, the conversion rate of dimethyl terephthalate can reach 83.29-99.96%, and the selectivity of dimethyl 1,4-cyclohexanedicarboxylate can reach 84.24-99.99%.

[0051] The present invention is described below by means of specific embodiments, but the present invention is not limited thereto.

[0052] [Example 1]

[0053] 1. Preparation of carrier γ-alumina:

[0054] 25 g of pseudo-boehmite was taken and placed in a muffle furnace with a heating rate of 5° C. / min. After calcination at 500° C. for 3 hours, a carrier γ-alumina was obtained, which was used as a precursor.

[0055] 2. Preparation of catalyst:

[0056] Dissolve 0.34 g of cobalt chloride, 0.51 g of nickel acetate, 1.6 g of zirconium sulfate, 0.9 g of niobium nitrate, and 0.18 g of palladium chloride in 50 ml of ethanol solution and mix well.

[0057] After the precursor was added to the metal salt solution, 15 ml of oleylamine was added to the solution and reacted in an oil bath at 80° C. for 10 hours.

[0058] After the reaction was completed, 100 ml of deionized water was added, and the mixture was transferred to a reactor and placed at 150° C. for reaction for 12 hours.

[0059] After cooling, the product in the reactor was filtered and dried at 120°C. After being completely dried, it was calcined in a N2 environment at 800°C, with a heating rate of 5°C / min and a calcination time of 2 hours.

[0060] 3. Application of catalyst:

[0061] 1.5 g of catalyst, 20 g of dimethyl terephthalate and 20 ml of cyclohexane as a reaction solvent were weighed and added to the reactor.

[0062] The reaction was carried out at a hydrogen pressure of 2.5 MPa and a reaction temperature of 150° C. for 3 hours. The conversion rate of dimethyl terephthalate was 99.96%, and the selectivity of 1,4-cyclohexane dimethyl ester was 99.99%.

[0063] [Example 2]

[0064] 1. Preparation of carrier γ-alumina:

[0065] 30 g of pseudo-boehmite was taken and placed in a muffle furnace with a heating rate of 5° C. / min. After being calcined at 700° C. for 3 hours, a carrier γ-alumina was obtained, which was used as a precursor.

[0066] 2. Preparation of catalyst:

[0067] Dissolve 0.42 g of cobalt carbonate, 0.5 g of nickel chloride, 1.4 g of zirconium acetate, 0.8 g of niobium sulfate, and 0.05 g of palladium nitrate in 50 ml of ethanol solution and mix well.

[0068] The precursor was added to the metal salt solution, 15 ml of oleylamine was added to the solution, and the mixture was reacted in an oil bath at 80° C. for 10 hours.

[0069] After the reaction was completed, 100 ml of deionized water was added, and the mixture was transferred to a reactor and placed at 120° C. for reaction for 12 hours.

[0070] After cooling, the product in the reactor was filtered and dried at 120°C. After being completely dried, it was calcined in a N2 environment at 750°C with a heating rate of 5°C / min and a calcination time of 2 hours.

[0071] 3. Application of catalyst:

[0072] 1.2 g of catalyst, 20 g of dimethyl terephthalate and 20 ml of cyclohexane as a reaction solvent were weighed and added to the reactor.

[0073] The reaction was carried out at a hydrogen pressure of 2.5 MPa and a reaction temperature of 150° C. for 3 hours, and the conversion rate of dimethyl terephthalate was 98.93% and the selectivity of 1,4-cyclohexane dimethyl ester was 99.12%.

[0074] [Example 3]

[0075] 1. Preparation of carrier γ-alumina:

[0076] 25 g of pseudo-boehmite was taken and placed in a muffle furnace with a heating rate of 5° C. / min. After being calcined at 700° C. for 1.5 hours, a carrier γ-alumina was obtained, which was used as a precursor.

[0077] 2. Preparation of catalyst:

[0078] 0.68 g of cobalt oxalate, 0.75 g of nickel nitrate, 1.2 g of zirconium chloride, 0.7 g of niobium chloride and 0.17 g of palladium sulfate were dissolved in 50 ml of ethanol solution and mixed evenly.

[0079] The precursor was added to the metal salt solution, 15 ml of oleylamine was added to the solution, and the mixture was reacted in an oil bath at 80° C. for 10 hours.

[0080] After the reaction was completed, 100 ml of deionized water was added, and the mixture was transferred to a reactor and placed at 120° C. for reaction for 12 hours.

[0081] After cooling, the product in the reactor was filtered and dried at 120°C. After being completely dried, it was calcined in a N2 environment at 750°C with a heating rate of 5°C / min and a calcination time of 2 hours.

[0082] 3. Application of catalyst:

[0083] 2 g of catalyst, 20 g of dimethyl terephthalate and 20 ml of cyclohexane as a reaction solvent were weighed and added to the reactor.

[0084] The reaction was carried out at a hydrogen pressure of 2.5 MPa and a reaction temperature of 150° C. for 3 hours, and the conversion rate of dimethyl terephthalate was 97.93% and the selectivity of 1,4-cyclohexane dimethyl ester was 98.9%.

[0085] [Example 4-24]

[0086] According to the preparation conditions listed in Table 1 and the detailed steps in the implementation scheme, the γ-alumina supported high entropy alloy catalyst described in Table 2 can be prepared. Subsequently, according to the catalyst application conditions proposed in Table 2, the reaction results shown in Table 2 can be obtained.

[0087] [Comparative Example 1]

[0088] Comparative Example 1 is compared with the five-element high entropy alloy catalyst supported by γ-alumina, which shows that the five-element high entropy alloy supported by γ-alumina has better catalytic performance in the reaction of hydrogenating dimethyl terephthalate to prepare dimethyl 1,4-cyclohexanedicarboxylate.

[0089] (1) The catalyst was prepared by the method of Example 1, except that the metal salts selected in step (2) were 0.42 g of cobalt carbonate, 0.5 g of nickel chloride, 1.4 g of zirconium acetate, and 0.8 g of niobium sulfate. The catalyst was prepared under the same other conditions.

[0090] (2) Catalyst evaluation: 1.5 g of catalyst, 20 g of dimethyl terephthalate and 20 ml of cyclohexane as a reaction solvent were weighed and added to a reactor. The reaction was carried out at a hydrogen pressure of 2.5 MPa and a reaction temperature of 150° C. for 3 h. The conversion rate of dimethyl terephthalate was 63.33%, and the selectivity of 1,4-cyclohexanedimethyl ester was 65.71%.

[0091] [Comparative Example 2]

[0092] Comparative Example 2 is a comparison with a five-element high entropy alloy catalyst supported on γ-alumina, which shows that the five-element high entropy alloy supported on γ-alumina has better catalytic performance in the reaction of hydrogenating dimethyl terephthalate to prepare dimethyl 1,4-cyclohexanedicarboxylate.

[0093] (1) The catalyst was prepared by the method of Example 1, except that the metal salt selected in step (2) was 0.42 g of cobalt carbonate, 0.5 g of nickel chloride, and 1.4 g of zirconium acetate. The catalyst was prepared under the other conditions unchanged.

[0094] (2) Catalyst evaluation: 1.5 g of catalyst, 20 g of dimethyl terephthalate and 20 ml of cyclohexane as a reaction solvent were weighed and added to a reactor. The reaction was carried out at a hydrogen pressure of 2.5 MPa and a reaction temperature of 150° C. for 3 h. The conversion rate of dimethyl terephthalate was 45.19%, and the selectivity of 1,4-cyclohexanedimethyl ester was 46.31%.

[0095] Table 1

[0096]

[0097]

[0098] Table 2

[0099]

[0100] By comparing the above examples with the comparative examples, it can be clearly seen that the γ-alumina-supported five-element high entropy alloy catalyst provided by the present invention has excellent catalytic performance in the reaction of preparing dimethyl 1,4-cyclohexanedicarboxylate by hydrogenation of dimethyl terephthalate. The catalyst is not only simple in preparation method and low in cost, but also can achieve high conversion rate and high selectivity under mild reaction conditions, and has significant economic benefits and industrial application value.

[0101] The catalyst of the present invention and its preparation method and application have the following significant technical effects:

[0102] 1. The catalyst provided by the present invention uses γ-alumina as a carrier and is loaded with five-element high-entropy alloy particles. The catalyst has excellent catalytic performance and can achieve efficient hydrogenation conversion of dimethyl terephthalate under mild conditions to produce 1,4-cyclohexanedicarboxylic acid dimethyl ester.

[0103] 2. The catalyst preparation method provided by the present invention is simple, easy to operate, and easy to industrialize. By adjusting the type and doping amount of the metal salt, catalysts with different catalytic properties can be prepared to meet the needs of different industrial fields.

[0104] 3. The catalyst provided by the present invention has high conversion rate and selectivity in the reaction of hydrogenating dimethyl terephthalate to prepare dimethyl 1,4-cyclohexanedicarboxylate, and the reaction conditions are mild, without the need for high temperature and high pressure, thereby reducing production costs and resource consumption.

[0105] 4. The catalyst provided by the present invention has a low content of precious metals, which effectively reduces the overall cost of the catalytic process and has significant economic benefits.

[0106] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0107] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A catalyst for use in the reaction of hydrogenating dimethyl terephthalate to prepare dimethyl 1,4-cyclohexanedicarboxylate, characterized in that: The catalyst uses γ-alumina as a carrier and is loaded with five-element high-entropy alloy particles containing five elements: Co, Ni, Zr, Nb, and Pd. The doping amount of Co is 0.1-25wt%, the doping amount of Ni is 0.1-30wt%, the doping amount of Zr is 30-80wt%, the doping amount of Nb is 10-35wt%, the doping amount of Pd is 1-5wt%, and the total amount of the five metal elements is 100wt%.

2. The catalyst according to claim 1, characterized in that: The doping amount of Co in the catalyst is 8.5-23.5wt%, the doping amount of Ni is 12.5-26.3wt%, the doping amount of Zr is 35.8-64.1wt%, the doping amount of Nb is 13.3-31.9wt%, and the doping amount of Pd is 1.2-4.6wt%.

3. A method for preparing a catalyst, wherein the catalyst is the catalyst according to claim 1 or 2, characterized in that The following steps are involved: (a) taking a certain amount of pseudo-boehmite and calcining it at a constant temperature in a muffle furnace for 1-6 hours to obtain a carrier γ-alumina as a precursor; (b) Dissolving metal salts of cobalt salt, zirconium salt, nickel salt, niobium salt and palladium salt in an alcohol solution and mixing them evenly, adding the precursor, and then adding oleylamine to the solution, and reacting in an 80°C oil bath for 10 hours; after the reaction is completed, adding deionized water, and transferring to a reactor, reacting at a temperature of 100-180°C for 12 hours; after cooling, filtering the product in the reactor and drying it, and then calcining in a N2 atmosphere to obtain a catalyst.

4. The preparation method according to claim 3, characterized in that: The calcination temperature in step (a) is 300-900° C., the calcination time is 3-5 hours, and the heating rate is 1-6° C. / min.

5. The preparation method according to claim 3, characterized in that: The amount of pseudo-boehmite used in step (a) is 15-35 g; the volume of the alcohol solution in step (b) is 50 ml, the amount of oleylamine added is 15 ml, the amount of deionized water added is 100 ml, and the product is dried at 120°C.

6. The preparation method according to claim 3, characterized in that: The alcohol in step (b) is one of anhydrous ethanol, isopropanol and methanol.

7. The preparation method according to claim 3, characterized in that: The cobalt salt in step (b) is one or more of cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt acetate, cobalt carbonate, and cobalt oxalate; the nickel salt is one or more of nickel chloride, nickel sulfate, nickel nitrate, nickel acetate, nickel carbonate, and nickel oxalate; the zirconium salt is one or more of zirconium chloride, zirconium sulfate, zirconium nitrate, and zirconium acetate; the niobium salt is one or more of niobium chloride, niobium sulfate, and niobium nitrate; and the palladium salt is one or more of palladium chloride, palladium nitrate, palladium sulfate, and sodium tetrachloropalladate.

8. The preparation method according to claim 7, characterized in that: The cobalt salt is cobalt acetate, the nickel salt is nickel acetate, the zirconium salt is zirconium chloride, the niobium salt is niobium chloride, and the palladium salt is palladium chloride.

9. The preparation method according to claim 3, characterized in that: The calcination temperature in step (b) is 500-900° C., the calcination time is 1-5 h, and the heating rate is 1-6° C. / min.

10. Use of the catalyst as claimed in claim 1 or 2 in the reaction of preparing dimethyl 1,4-cyclohexanedicarboxylate by hydrogenation of dimethyl terephthalate.

11. The use according to claim 10, characterized in that: Add dimethyl terephthalate, catalyst and reaction solvent into a reactor, fill with hydrogen to replace the air in the reactor, then pressurize to 0.5-5MPa, and react at 120-250°C for 3h; the mass ratio of the catalyst to dimethyl terephthalate is 1:(3-30).

12. The use according to claim 11, characterized in that: The conversion rate of dimethyl terephthalate is 83.29-99.96%, and the selectivity of dimethyl 1,4-cyclohexanedicarboxylate is 84.24-99.99%.

Images