A maleic anhydride esterification hydrogenation catalyst, its preparation method and application

Abstract

The application discloses a catalyst for esterification and hydrogenation of maleic anhydride to prepare 1,4-butanediol as well as a preparation method and application thereof. 2n The catalyst is Cu-M-C 2n at least one selected from fullerene and derivative materials, 2n is the number of carbon atoms of the fullerene material, and 60<=2n<=120. The catalyst is used for hydrogenation reaction of dialkyl maleate / dialkyl succinate, can selectively prepare 1,4-butanedioic acid, and can produce tetrahydrofuran and gamma-butyrolactone, and has the advantages of high activity, good selectivity and long running life.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of maleic anhydride hydrogenation, and particularly relates to a maleic anhydride esterification hydrogenation catalyst and a preparation method and application thereof. BACKGROUND

[0002] Maleic anhydride is an important chemical product with C4 as raw material in the chemical industry, which can be prepared by n-butane oxidation method and benzene oxidation method. It is the third largest acid anhydride raw material in the world, only next to acetic anhydride and phthalic anhydride. The n-butane method for preparing maleic anhydride has low energy consumption and small pollution, and is favored by many manufacturers. Maleic anhydride esterification and hydrogenation technology is a key technology for producing degradable material monomer 1,4-butanediol. Maleic anhydride is esterified to form dimethyl maleate, and then hydrogenated to prepare 1,4-butanediol. The reaction is a three-step hydrogenation reaction. The first step is that dimethyl maleate is rapidly hydrogenated to form dimethyl succinate under the action of a catalyst; the second step is that dimethyl succinate is hydrogenated to form gamma-butyrolactone; and the third step is that gamma-butyrolactone is hydrogenated to form 1,4-butanediol.

[0003] The hydrogenation process of dimethyl maleate cannot be carried out without the catalysis of a catalyst. Among many heterogeneous catalyst systems, a copper (Cu) -based catalyst is low in price and has high activity for hydrogenation of dimethyl maleate due to its unique hydrogen activation ability of C=C hydrogenation and C=O bond breaking, and can produce 1,4-butanediol from dimethyl maleate under mild conditions. However, the Tammann temperature of the Cu-based catalyst is low, and Cu nanoparticles are easy to sinter at high temperature, which leads to poor running stability of the catalyst and hinders the industrial application of the Cu-based catalyst.

[0004] Adding an additive to the Cu-based catalyst helps to improve the stability of the catalyst and prolong the service life of the catalyst. CN103769105A discloses a catalyst preparation method for loading Ni and Cu metals by kneading diatomite and silica gel as a carrier. CN101502802A discloses a preparation method of a bimetallic catalyst doped with Cu by using metal Ni and taking SiO2 and / or Al2O3 as a carrier. The above catalysts have certain improvement in stability, but their catalytic activity and stability still need to be further improved. SUMMARY

[0005] The application provides a maleic anhydride esterification hydrogenation catalyst and a preparation method and application thereof. The catalyst of the application is used for hydrogenation reaction of dialkyl maleate / dialkyl succinate, can prepare 1,4-butanediol with high selectivity and produce tetrahydrofuran and y-butyrolactone, and has the advantages of high activity, good selectivity and long running life.

[0006] The first aspect of the application provides a maleic anhydride esterification hydrogenation catalyst for preparing 1,4-butanediol, wherein the catalyst is Cu-M-C 2nThe catalyst, wherein M is one or more of Zn, Al, Ba, Mn, Mg, Ti, Ge, Zr, Cr, Pd, Ag, Au, preferably one or more of Zn and Al; C 2n at least one selected from fullerene and derivative materials thereof, 2n is the number of carbon atoms of the fullerene material, 60≤2n≤120.

[0007] In the catalyst, the content of copper oxide is 20%-59%, the content of M is 40%-79% as calculated in terms of oxide, and the content of C 2n is 0.5%-5%, based on the weight of the catalyst.

[0008] In the catalyst, preferably, the content of copper oxide is 39%-50%, the content of M is 49%-60% as calculated in terms of oxide, and the content of C 2n is 0.8%-1.5%, based on the weight of the catalyst.

[0009] In the catalyst, the fullerene material is selected from at least one of C 60 , C 70 and derivatives thereof (such as PC61BM, PC71BM, etc.).

[0010] The catalyst has the following properties: specific surface area 20-60 m 2 / g, pore volume 0.2-0.4 mL / g, and average pore diameter 15-25 nm.

[0011] The second aspect of the present application provides a preparation method of the above hydrogenation catalyst, comprising:

[0012] (1) uniformly mixing F-127 with C 2n , then mixing with water, and then adding the mixture into a high-pressure homogenizer to perform homogenization, to obtain a mixture;

[0013] (2) co-precipitating a solution containing Cu and M, the mixture obtained in step (1) and a precipitant solution at 20-60°C, keeping the precipitate slurry stirring, the pH value of the system is 4.0-8.0, and after the co-precipitation is completed, the constant-temperature stirring is continued for 30-120 minutes;

[0014] (3) filtering and drying the precipitate obtained in step (2);

[0015] (4) calcining the dried product obtained in step (3) to obtain the catalyst.

[0016] In the method, in step (1), the polyoxyethylene polyoxypropylene (F-127) is a polyadduct of polypropylene glycol and ethylene oxide, and the average molecular weight is 11000-13000.

[0017] In the method, in step (1), the particle size of the C 2n is 200-900 nm.

[0018] In the method, in step (1), the mass ratio of F-127 to C 2n is 5-50, preferably 10-20.

[0019] In the method, in step (1), the water is preferably deionized water. The concentration of C 2n in the mixed solution is 1-40 g / L, preferably 5-10 g / L.

[0020] In the method, the homogenization conditions in step (1) are as follows: the pressure is 35-45 MPa, the time is 1-10 hours, preferably 2-5 hours, the temperature is 20-50℃, preferably 25-35℃, and the homogenization is performed 3-10 times.

[0021] In the method, the mixture obtained in step (1) can be filtered before step (2). The screen used for filtering is more than 50 mesh, further 50-90 mesh, preferably 70-80 mesh.

[0022] In the method, in step (2), the total concentration of Cu and M metal ions in the solution containing Cu and M is 0.1-4.0 mol / L, preferably 0.5-2.0 mol / L. The concentration of the precipitant solution is 1.0-5.0 mol / L, preferably 2.0-3.0 mol / L. The precipitant can be selected from at least one of potassium bicarbonate, potassium carbonate, ammonia, etc.

[0023] In the method, when preparing the solution containing Cu and M, soluble salts of Cu and M can be used, which can be at least one of nitrate, acetate or oxalate. The used soluble salts and precipitants preferably do not contain Na + , Cl - , SO4 2- ions.

[0024] In the method, in step (2), the pH value of the parallel flow precipitation is 4-8, and the reaction time is 0.5-1.5 hours.

[0025] In the method, in step (3), the drying conditions are as follows: the drying temperature is 100-130℃, and the drying time is 2-15 hours.

[0026] In the method, in step (3), the precipitate obtained in step (2) is directly filtered without intermediate treatment such as washing, and the solid phase obtained by filtering is dried.

[0027] In the method, the step (4) roasting preferably adopts two-stage roasting, wherein the first stage is low-temperature roasting, the roasting temperature is 240-400 DEG C, the roasting time is 6-10 hours, the second stage is high-temperature roasting, the roasting temperature is 500-700 DEG C, and the roasting time is 2-6 hours, preferably, the roasting needs programmed temperature rising, and the temperature rising rate is 1-5 DEG C / min.

[0028] The third aspect of the application provides application of the above-mentioned catalyst in maleic acid dialkyl ester / succinic acid dialkyl ester hydrogenation reaction.

[0029] In the application, the maleic acid dialkyl ester / succinic acid dialkyl ester is generally C1-C4 dialkyl ester, such as dimethyl maleate (dimethyl maleate) / dimethyl succinate, diethyl maleate / succinate, diethyl succinate, dibutyl maleate / succinate and the like.

[0030] In the application, the catalyst needs to be reduced and activated before use, preferably, the reducing gas is hydrogen, and the conditions are as follows: the pressure is 1-4 MPa, the temperature is 150-190 DEG C, the time is 5-20 h, and the hydrogen volume space velocity is 70-120 h -1 .

[0031] In the application, the hydrogenation reaction conditions are as follows: the reaction pressure is 1-6 MPa, the reaction temperature is 160-240 DEG C, preferably, the reaction temperature is 180-200 DEG C, the hydrogen-ester molar ratio is 50:1-400:1, preferably, the hydrogen-ester molar ratio is 100:1-300:1, and the liquid hourly space velocity is 0.1-2 h -1 , preferably, the liquid hourly space velocity is 0.2-0.5 h -1 .

[0032] Compared with the prior art, the application has the following advantages:

[0033] 1、The preparation method of the catalyst in the application adopts F127 which has hydrophilic and lipophilic groups, can form 200-900 nm nanomicelles with fullerene materials and be uniformly dispersed in the aqueous phase, solves the problem that fullerene is difficult to uniformly disperse in an aqueous solution, and improves the Cu-M-C 2nThe dispersity of the fullerene additive in the catalyst is beneficial to the interaction between the fullerene material and the active metal Cu, so that the content of cuprous in the ternary catalyst can be stabilized, and the stability of the active metal copper nanoclusters in the catalyst at high temperature can be ensured. The two-stage roasting is preferred in the application, so that the F127 polymer can be fully pyrolyzed, and the slow release of CO2 gas can avoid the damage to the structure of the fullerene, and the stability of the fullerene in the catalyst preparation process can be improved. The catalyst preparation method in the application takes the environment-friendly polymer material F127 as a dispersion medium, the solution is aqueous phase, the F127 material is decomposed in roasting, and no pollutants are generated, so that the preparation process is environmentally friendly and pollution-free.

[0034] 2. The catalyst in the application is used for the hydrogenation reaction of dialkyl maleate / dialkyl succinate, and can be used to prepare 1,4-succinic acid with high selectivity and produce tetrahydrofuran and gamma-butyrolactone, and has the advantages of high activity, good selectivity and long running life, that is, the conversion rate is greater than 99%, the total selectivity is greater than 98%, and the running life is more than 5000 hours. DETAILED DESCRIPTION

[0035] The catalyst preparation process for producing 1,4-butanediol co-produced tetrahydrofuran and gamma-butyrolactone is further described in the following specific embodiments. In the application, wt% is the mass fraction.

[0036] In the application, the determination of metal ions is that 60 mL of acetic acid (concentration of 10 wt%) and 5 g of catalyst powder are stirred at room temperature for 30 minutes, and then the solution is separated, filtered and washed, and the content of metal ions in the solution is quantitatively analyzed by the ICP method. In the application, the specific surface area, pore volume and pore size are determined by the low-temperature liquid nitrogen adsorption (BET) method.

[0037] The catalyst activity provided by the application can be evaluated by the following method:

[0038] The catalyst activity is evaluated in a micro fixed bed reactor. The roasting catalyst powder is granulated to 50 mesh by a granulator, and is loaded into a micro reactor reaction tube, and is reduced and activated by diluted H2 gas, and the conditions are as follows: pressurized to 2 MPa, and the catalyst is activated at 160℃ for 10 h by hydrogen (volume space velocity is 90 h -1 ) of the raw material dimethyl maleate is pumped into the reaction tube by a feeding pump, and then the reaction is carried out by pressurizing and heating.

[0039] Example 1

[0040] (1) 108 g of F-127 is mixed with 7.2 g of fullerene C 60(100-380 nm in size) were mixed well, then 500 mL of deionized water was added for mixing, and the mixed solution was added into a high-pressure homogenizer for homogenization, with a pressure of 40 MPa, a homogenization time of 3 hours, a temperature of 25 °C, and 3 times of homogenization, to obtain a mixed solution, which was filtered through a 60-mesh screen to obtain C 60 @F127 mixture;

[0041] (2) At 20 °C, 2000 mL of a mixed solution containing 843 g of Cu(NO3) 2· 3H2O and 859 g of Zn(NO3)2·6H2O and 500 mL of a precipitant ammonia water (3.52 mol / L in molar concentration) were added into a co-precipitation system with C 60 @F127 (C 60 14.4 g / L in concentration) mixture, and the pH value of the precipitation system was maintained at 5.8, and constant-temperature stirring was continued for 50 minutes after the addition was completed;

[0042] (3) The product obtained in step (2) was rapidly evaporated at 120 °C, then the temperature was increased to 300 °C at a rate of 2 °C / min, and the temperature was maintained for 8 hours, then the temperature was increased to 600 °C at a rate of 4 °C / min, and the temperature was maintained for 2 hours. The obtained catalyst was granulated into 50 mesh by tabletting, and was loaded into a micro-reactor for activity evaluation.

[0043] Example 2

[0044] (1) 89 g of F-127 was mixed with 8.9 g of fullerene C 70 (200-350 nm in size) were mixed well, then 600 mL of deionized water was added for mixing, and the mixed solution was added into a high-pressure homogenizer for homogenization, with a pressure of 40 MPa, a homogenization time of 5 hours, a temperature of 30 °C, and 3 times of homogenization, to obtain a mixed solution C 70 @F127 mixture;

[0045] (2) At 50 °C, 1900 mL of a mixed solution containing 993.13 g of Cu(NO3)2·3H2O and 881.74 g of Al(NO3)3·9H2O and 600 mL of a precipitant ammonia water (3.52 mol / L in molar concentration) were added into a co-precipitation system with C 70 @F127 (C 70 14.83 g / L in concentration) mixture, and the pH value of the precipitation system was maintained at 6.3, and constant-temperature stirring was continued for 60 minutes after the addition was completed;

[0046] (3) The product obtained in step (2) was rapidly evaporated at 110°C, then heated to 300°C at a rate of 1°C / min and held at that temperature for 6 hours, and then heated to 600°C at a rate of 5°C / min and held at that temperature for 3 hours. The resulting catalyst was granulated to 50 mesh and loaded into a microreactor for activity evaluation.

[0047] Example 3

[0048] (1) Mix 34g F-127 with 1.7g [6,6]-phenyl-C71-butyric acid isomethyl ester (PC71BM) (particle size 170-320nm) evenly, then add 750mL of deionized water and mix. Then add the mixture to a high-pressure homogenizer for homogenization at a pressure of 40MPa for 2 hours at a temperature of 25℃. Homogenize 3 times. Filter the solution through a 70-mesh sieve to obtain the PC71BM@F127 mixture.

[0049] (2) At 60℃, 1750 mL of a mixed solution containing 251 g Cu(NO3)2·3H2O and 364.6 g Zr(NO3)4·5H2O and a mixture of precipitant ammonia water (molar concentration of 3.52 mol / L) and PC71BM@F127 (concentration of 2.3 g / L) were added dropwise in parallel to co-precipitate the mixture, while maintaining the pH of the precipitation system at 7.2. After the addition was completed, the mixture was stirred at a constant temperature for 40 minutes.

[0050] (3) The product obtained in step (2) was rapidly evaporated at 130°C, then heated to 300°C at a rate of 3°C / min and held at that temperature for 4 hours, and then heated to 600°C at a rate of 5°C / min and held at that temperature for 3 hours. The resulting catalyst was granulated to 50 mesh and loaded into a microreactor for activity evaluation.

[0051] Example 4

[0052] (1) Mix 108g of F-127 with 7.2g of fullerene C 60 Mix the particles (100-380nm) thoroughly, then add 500mL of deionized water and mix. Then add the mixture to a high-pressure homogenizer for homogenization at a pressure of 40MPa for 3 hours at a temperature of 25℃. Homogenize 3 times to obtain a mixed solution. Filter the solution through a 60-mesh sieve to obtain the C60@F127 mixture.

[0053] (2) At 20°C, 2000 mL of mixed solution containing 843 g Cu(NO3)2-3H2O and 859 g Zn(NO3)2-6H2O and 500 mL of precipitant ammonia water (molar concentration of 3.52 mol / L) and C60@F127 (C60 concentration of 14.4 g / L) mixture were co-precipitated by dropwise adding in parallel, and the pH value of the precipitation system was kept at 5.8, and after the dropwise adding was completed, constant temperature stirring was continued for 50 minutes;

[0054] (3) The product obtained in step (2) was quickly evaporated dry at 120°C, and the obtained product was heated to 600°C at a rate of 2°C / min, and kept constant temperature for 2 hours. The obtained catalyst was granulated to 50 mesh, and loaded into a micro-reactor for activity evaluation.

[0055] Comparative Example 1

[0056] (1) At 20°C, 2000 mL of mixed solution containing 843 g Cu(NO3) 2· 3H2O and 859 g Zn(NO3)2-6H2O and 500 mL of precipitant ammonia water (molar concentration of 3.52 mol / L) and C60@F127 (C60 concentration of 14.4 g / L) mixture were co-precipitated by dropwise adding in parallel, and the pH value of the precipitation system was kept at 5.8, and after the dropwise adding was completed, constant temperature stirring was continued for 50 minutes;

[0057] (2) The product obtained in step (1) was quickly evaporated dry at 120°C, and then heated to 300°C at a rate of 2°C / min, and kept constant temperature for 8 hours, and then heated to 600°C at a rate of 4°C / min, and kept constant temperature for 2 hours. The obtained catalyst was granulated to 50 mesh, and loaded into a micro-reactor for activity evaluation.

[0058] Comparative Example 2

[0059] At 20°C, 843 g Cu(NO3) 2· 3H2O, 859 g Zn(NO3)2-6H2O were added to a fullerene C 60 (100-380 nm in particle size) suspension (concentration of 14.4 g / L) to form a mixed solution and precipitant ammonia water (molar concentration of 3.52 mol / L) to carry out parallel precipitation, and the pH value was adjusted to 5.8, and stirring was continued for 50 minutes. The precipitate was filtered, and then quickly evaporated dry at 120°C, and then heated to 300°C at a rate of 2°C / min, and kept constant temperature for 8 hours, and then heated to 600°C at a rate of 4°C / min, and kept constant temperature for 2 hours. The obtained catalyst was granulated to 50 mesh, and loaded into a micro-reactor for activity evaluation.

[0060] Comparative Example 3

[0061] (1) 108 g F-127 and 7.2 g fullerene C 60(100-380 nm) was added into 500 mL deionized water to obtain a mixed solution, which was filtered through a 60 mesh screen to obtain C 60 @F127 mixture;

[0062] (2) A mixed solution containing 843 g Cu(NO3) 2· 3H2O and 859 g Zn(NO3)2·6H2O 2000 mL and a precipitant ammonia water (molar concentration of 3.52 mol / L) were added into 500 mL C 60 @F127 (C 60 mixture 500 mL at a flow rate, and the pH value of the precipitation system was maintained at 5.8; after the addition was completed, the stirring was continued for 50 minutes at constant temperature;

[0063] (3) The product obtained in step (2) was rapidly evaporated at 120℃, then heated to 300℃ at a rate of 2℃ / min, and kept at 300℃ for 8 hours, then heated to 600℃ at a rate of 4℃ / min, and kept at 600℃ for 2 hours. The obtained catalyst was granulated to 50 mesh, and loaded into a micro-reactor for activity evaluation.

[0064] Table 1 Composition and physicochemical properties of the catalysts obtained in each example

[0065] Composition, wt% Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 CuO 42.5 44.2 43.7 42.5 43.0 42.5 42.5 M, as oxide 56.4 54.6 55.4 56.4 57 56.4 56.4 C 2n ]]> 1.1 1.2 0.9 1.1 0 1.1 1.1 Specific surface area, m 2 / g]]> 48 43 45 39 40 38 46 Pore volume, ml / g 0.28 0.23 0.24 0.17 0.15 0.18 0.21 Average pore diameter, nm 23 21 21 17 15 19 18

[0066] Table 2 Process conditions

[0067] Raw material Dimethyl maleate Reaction temperature / °C 190 Liquid hourly space velocity / h -1 ]] 0.25 Reaction pressure / MPa 6 Hydroester molar ratio 300

[0068] Table 3 Activity evaluation results of the catalysts in each example

[0069]

[0070]

[0071] Table 4 Catalyst evaluation results at different running times

[0072]

[0073] Note: The conversion in the table is in mole fraction, and the total selectivity of the product is in mole fraction, which refers to the sum of the selectivity of 1,4-butanediol, tetrahydrofuran, γ-butyrolactone and n-butanol obtained after esterification and hydrogenation of maleic anhydride.

Claims

1. A catalyst for the hydrogenation of maleic anhydride to 1,4-butanediol, wherein the catalyst is Cu-MC 2n Catalyst, wherein M is one or more of Zn, Al, Ba, Mn, Mg, Ti, Ge, Zr, Cr, Pd, Ag, and Au, and C 2n Selected from at least one of fullerenes and their derivatives, where 2n is the number of carbon atoms in the fullerene material, and 60≤2n≤120; Based on the weight of the catalyst, the copper oxide content is 39%-50%, the M content (calculated as oxides) is 49%-60%, and the C content is... 2n The content is 0.8%-1.5%; The method for preparing the hydrogenation catalyst includes: (1) The F-127 and C 2n Mix thoroughly, then mix with water, and then add the mixture to a high-pressure homogenizer for homogenization to obtain a mixture; (2) At 20-60℃, the solution containing Cu and M, the mixture obtained in step (1) and the precipitant solution are co-precipitated in parallel flow. The precipitate slurry is stirred and the pH value of the system is 4.0-8.

0. After the co-flow is completed, the mixture is stirred at a constant temperature for 30-120 minutes. (3) Filter and dry the precipitate obtained in step (2); (4) The dried material obtained in step (3) is calcined to obtain the catalyst; In step (1), the C 2n The particle size is 200-900 nanometers; F-127 and C 2n The mass ratio is 10-20; the C in the mixture 2n The concentration is 5-15 g / L; The homogenization conditions described in step (1) are as follows: pressure 35-45 MPa, time 2-5 hours, temperature 25-35℃, homogenization 3-10 times; Step (4) involves two stages of roasting. The first stage is low-temperature roasting at 240-400℃ for 6-10 hours, while the second stage is high-temperature roasting at 500-700℃ for 2-6 hours.

2. The catalyst according to claim 1, characterized in that, The fullerene material is selected from C 60 C 70 At least one of its derivatives.

3. The catalyst according to claim 1, characterized in that, The catalyst has the following properties: specific surface area of ​​20-60 m² 2 / g, pore volume is 0.2-0.4mL / g, and average pore size is 15-25nm.

4. A method for preparing the hydrogenation catalyst according to any one of claims 1-3, comprising: (1) The F-127 and C 2n Mix thoroughly, then mix with water, and then add the mixture to a high-pressure homogenizer for homogenization to obtain a mixture; (2) At 20-60℃, the solution containing Cu and M, the mixture obtained in step (1) and the precipitant solution are co-precipitated in parallel flow. The precipitate slurry is stirred and the pH value of the system is 4.0-8.

0. After the co-flow is completed, the mixture is stirred at a constant temperature for 30-120 minutes. (3) Filter and dry the precipitate obtained in step (2); (4) The dried material obtained in step (3) is calcined to obtain the catalyst; In step (1), the C 2n The particle size is 200-900 nanometers; F-127 and C 2n The mass ratio is 10-20; the C in the mixture 2n The concentration is 5-15 g / L; The homogenization conditions described in step (1) are as follows: pressure 35-45 MPa, time 2-5 hours, temperature 25-35℃, homogenization 3-10 times; Step (4) involves two stages of roasting. The first stage is low-temperature roasting at 240-400℃ for 6-10 hours, while the second stage is high-temperature roasting at 500-700℃ for 2-6 hours.

5. The method according to claim 4, characterized in that, The mixture obtained in step (1) is filtered before step (2), and the sieve used for filtration is 50 mesh or larger.

6. The method according to claim 4, characterized in that, The mixture obtained in step (1) is filtered before step (2). The sieve used for filtration is 50-90 mesh.

7. The method according to claim 4, characterized in that, The mixture obtained in step (1) is filtered before step (2). The sieve used for filtration is 70-80 mesh.

8. The method according to claim 4, characterized in that, In step (2), the total concentration of Cu and M metal ions in the Cu and M solution is 0.5-2.0 mol / L; the concentration of the precipitant solution is 2.0-3.0 mol / L; and the precipitant is selected from at least one of potassium bicarbonate, potassium carbonate, and ammonia water.

9. The method according to claim 4, characterized in that, The pH value of the co-current precipitation in step (2) is 4-8, and the reaction time is 0.5-1.5 hours; and / or, the drying conditions in step (3) are as follows: the drying temperature is 100-130℃, and the drying time is 2-15 hours.

10. The method according to claim 4, characterized in that, In step (4), the roasting process requires programmed heating at a rate of 1-5℃ / minute.

11. The use of the catalyst according to any one of claims 1-3 in the hydrogenation reaction of dialkyl maleate / dialkyl succinate.

12. The application according to claim 11, characterized in that, The dialkyl maleate / dialkyl succinate is a C1-C4 dialkyl ester.

13. The application according to claim 11, characterized in that, The hydrogenation reaction conditions are as follows: reaction pressure 1-6 MPa, reaction temperature 160-240℃, hydrogen-ester molar ratio 50:1-400:1, and liquid hourly space velocity 0.1-2 h⁻¹. -1 .

14. The application according to claim 13, characterized in that, The hydrogenation reaction conditions are as follows: reaction temperature 180-200℃, hydrogen-ester molar ratio 100:1-300:1, and liquid hourly space velocity (LISH) 0.2-0.5 h⁻¹. -1 .

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