Preparation method and application of maleic anhydride hydrogenation catalyst

Abstract

The present invention belongs to the technical field of catalytic hydrogenation, and discloses a preparation method and application of a maleic anhydride hydrogenation catalyst. The present invention provides a maleic anhydride hydrogenation catalyst, with Al2O3 as the carrier, Ni as the active component, and a first modifying assistant, alkaline earth metal, added to form a BaAl2O4 spinel film on the surface of the Al2O3 carrier under the condition of high-temperature calcination; then a second modifying assistant, rare earth metal, is added and jointly promoted by a complexing agent to obtain a hydrogenation catalyst with high reaction activity and high stability. This catalyst enables the maleic anhydride conversion rate to reach 100%. When the reaction is carried out at low temperature and low pressure, the selectivity of succinic anhydride is as high as over 99%. When the reaction is carried out at relatively high temperature and pressure, the selectivity of γ-butyrolactone can reach over 90%. Moreover, different product compositions can be controlled by adjusting the reaction conditions, achieving the purpose of simultaneously preparing and producing two products, and reducing equipment costs and production costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical catalysis, and particularly relates to a preparation method and application of a catalyst for hydrogenating maleic anhydride to succinic anhydride and γ-butyrolactone, which is applicable to both batch reactions and continuous reactions. Background Art

[0002] Succinic anhydride, also known as amber acid anhydride, is an important organic synthesis intermediate and fine chemical raw material, and is widely used in the fields of food, surfactants, coatings, medicine, agriculture, plastics, etc. Especially in the plastics industry, the hydrolysis product of succinic anhydride, succinic acid, and butanediol can be polycondensed to obtain a biodegradable plastic with excellent performance - polybutylene succinate (PBS). With the increasingly severe problem of white pollution, the market prospect of the biodegradable plastic PBS is very broad.

[0003] γ-Butyrolactone is an important fine organic chemical intermediate, which has very high solubility and can be miscible with water. It can dissolve common organic substances such as methanol, ethanol, and benzene, and can also dissolve polymers such as epoxy resin and polyvinyl chloride. Due to its excellent physical and chemical properties, γ-butyrolactone is often used as an organic solvent and reaction reagent in chemistry, and it is also used as an extractant and adsorbent. The special molecular structure of γ-butyrolactone makes it have the chemical properties of alicyclic lactones and can undergo a series of ring-opening or non-ring-opening chemical reactions. Its special chemical properties make it widely used in the fields of petrochemistry, agriculture, medicine, textiles, etc.

[0004] The main maleic anhydride hydrogenation catalysts are noble metal catalysts, copper-based catalysts, and nickel-based catalysts. Noble metal catalysts are common hydrogenation reaction catalysts, commonly including palladium, ruthenium, platinum, gold, etc., which have high catalytic activity and comprehensive excellent properties such as antioxidant, high temperature resistance, and corrosion resistance. However, their disadvantage is that the price is relatively expensive. Copper-based catalysts have been widely concerned due to their low price. However, the maleic anhydride hydrogenation reaction conditions of copper-based catalysts are relatively harsh, requiring higher reaction temperature and reaction pressure, and the selectivity of succinic anhydride is relatively low. Therefore, the research mainly focuses on the deep hydrogenation of maleic anhydride. Nickel-based catalysts have a lower price than noble metal catalysts and can show high conversion of maleic anhydride and high selectivity to succinic anhydride at lower reaction temperature and pressure. However, the performance of the catalyst is often affected by various factors such as the nature of the carrier, calcination temperature, and additives. Improving the service life and stability of nickel-based catalysts is the research focus.

[0005] Patent EP0691335 discloses a method for the one-step hydrogenation of maleic anhydride to succinic anhydride in the presence of a solvent. The catalyst used is noble metal Pd, and the noble metal content is as high as 2-10 wt%. Under the reaction pressure of 4.0-6.0 MPa, the yield of succinic anhydride is 90-95%. The noble metal content of this catalyst is relatively large, and the preparation cost of the catalyst is high, which is not conducive to large-scale production. Moreover, this reaction requires a high reaction pressure and high equipment energy consumption. Patent CN113332986A discloses a catalyst for the hydrogenation of maleic anhydride to succinic anhydride containing a spinel structure. The prepared spinel is impregnated in a metal precursor solution, stirred, dried, calcined and reduced to obtain the catalyst. However, the preparation time of the spinel support of this catalyst is relatively long, and there is still room for improvement in catalytic activity and stability. Patent CN104399469A provides a preparation method of a nickel-based catalyst. This catalyst is a nickel-based catalyst supported on alumina. At a reaction temperature of 120 °C, a reaction pressure of 0.5 MPa, and a space velocity of 2 h -1 After running for 50 h under the condition, the selectivity of succinic anhydride is only 86%. The stability of the catalyst is insufficient and the service life is relatively low, which is not suitable for long-term industrial production, and the hydrogenation product is single. Under the existing catalyst reaction, the hydrogenation product of maleic anhydride is often very single and has a high reaction specificity. There are very few reported hydrogenation catalysts for the co-production of γ-butyrolactone by the hydrogenation of maleic anhydride to succinic anhydride. Patent CN114917897A discloses a catalyst for the synthesis of γ-butyrolactone and the co-production of succinic anhydride, its preparation method and application. Although it can achieve the co-production of two different products under certain conditions, its catalyst preparation process is complex. It is necessary to add a flocculant, a carrier and an aqueous solution of a transition metal compound to form a precipitate, and a solid acid precursor compound is also needed for adjustment. The process is cumbersome and the finished product effect is unstable, which is not suitable for industrial production. Summary of the Invention

[0006] In order to solve the problems in the background technology, the purpose of the present invention is to provide a catalyst for the hydrogenation of maleic anhydride to succinic anhydride and γ-butyrolactone. By adjusting the reaction temperature and pressure, this catalyst can realize the generation of different main products of succinic anhydride and γ-butyrolactone. The purpose of using the same catalyst to prepare and produce two products is achieved, reducing equipment costs and production costs. Moreover, the catalyst preparation process is simple, the finished product effect of the catalyst is stable, and it is suitable for industrial application.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a maleic anhydride hydrogenation catalyst, using Al2O3 as the carrier, Ni as the active component, adding a first modifying assistant, alkaline earth metal (taking Ba as an example), to form a BaAl2O4 spinel film on the surface of the Al2O3 carrier under the condition of high-temperature calcination, thereby improving the interaction between the carrier and the active component and the thermal stability of the catalyst; then adding a second modifying assistant, rare earth metal (taking Ce as an example), and preparing a hydrogenation catalyst with high reaction activity and high stability under the co-promotion of the complexing agent citric acid.

[0009] The specific preparation steps of the maleic anhydride hydrogenation catalyst provided by the present invention are as follows:

[0010] (1) Weigh the dried Al2O3 as the carrier, and impregnate the Al2O3 carrier with a barium salt solution by the equal-volume impregnation method. That is, put the weighed Al2O3 carrier into a container, then add the prepared barium salt solution into the container in sequence and stir continuously, impregnate in a constant-temperature water bath at 70 - 80 °C for 1 - 5 h; then dry at a constant temperature in an oven at 105 °C for 2 - 12 h; put the dried catalyst into a muffle furnace at 600 - 1000 °C and program the temperature rise for calcination for 3 - 8 h.

[0011] (2) Add the calcined catalyst in step (1) to an equal-volume mixed solution of nickel salt, cerium salt and complexing agent prepared, and impregnate for 2 - 12 hours. Put the impregnated catalyst into an oven at 105 °C and dry at a constant temperature for 2 - 12 hours. Put the dried catalyst into a muffle furnace at 200 - 600 °C and program the temperature rise for calcination for 2 - 6 hours.

[0012] (3) Reduction treatment: When the product obtained by calcination in step (2) is used, directly introduce hydrogen for reduction in a fixed micro-bed reactor. The reduction temperature is 200 - 600 °C, the best is 450 °C, and the reduction time is 2 - 6 h.

[0013] Further, the specific surface area of the Al2O3 carrier in step (1) is 200 - 250 m 2 / g, the pore volume is 0.5 - 0.8 cm 2 / g, and the average pore diameter is 6 - 10 nm.

[0014] Further, the barium salt is one or several of barium nitrate, barium sulfate, barium chloride, barium carbonate, barium acetate; preferably barium nitrate. The nickel salt is one or several of nickel nitrate, nickel chloride, nickel oxalate, nickel acetate or nickel sulfate. The cerium salt is one or several of cerium carbonate, cerium sulfate, cerium nitrate, cerium chloride, cerium acetate; preferably cerium nitrate. The complexing agent is one or several of citric acid, monoethanolamine, diethanolamine, ethylenediamine, acetylacetone.

[0015] Further, the temperature-programmed conditions in step (2) are as follows: starting from the initial temperature, the temperature is raised to the required calcination temperature at a heating rate of 2 °C / min, maintained at this temperature for 2 to 6 h, and then lowered to room temperature.

[0016] The mass fraction of the active component nickel in the catalyst is 5 to 20% of the mass of the support, the mass fraction of Ba is 1 to 7% of the mass of the support, the mass fraction of Ce is 1 to 5% of the mass of the support, and the rest is the support. The molar ratio of the complexing agent citric acid to Ni is 1:2.

[0017] In the present invention, the addition of the modified first promoter barium forms a BaAl2O4 spinel film on the surface of the support under high-temperature calcination, which not only reduces the surface acidity of the catalyst and enhances the surface basicity, but also the support with a spinel structure can enhance the interaction between the active component and the thermal stability of the catalyst. The addition of the promoter increases the surface basicity, which has an inhibitory effect on the hydrogenation of C=O on maleic anhydride under low-temperature and low-pressure reaction conditions, reduces the formation of polymers, and improves the selectivity of succinic anhydride. Moreover, it also has excellent hydrogenation activity under high-temperature and high-pressure reaction conditions, and has a high selectivity for the deep hydrogenation product γ-butyrolactone. At the same time, due to the high thermal stability of the catalyst, the migration, aggregation, and carbon deposition deactivation problems of the active component are effectively inhibited at high temperatures, greatly improving the service life of the catalyst. The addition of the modified promoter cerium in the present invention improves the dispersion of the active phase on the surface of the support, inhibits the aggregation of the Ni component, makes the active component nickel more uniformly dispersed, strengthens the interaction between the active component and the support, reduces the loss of the active component Ni in the catalyst, improves the anti-carbon deposition ability of the catalyst, and makes the catalyst have high activity and high stability.

[0018] Application of the catalyst in the preparation of succinic anhydride and γ-butyrolactone by maleic anhydride hydrogenation in a fixed bed:

[0019] The maleic anhydride solution and hydrogen are respectively controlled to enter the reaction through a feed pump and a flow meter. Under the action of the catalyst after reduction activation, when the reaction temperature is controlled at 60 to 80 °C and the reaction pressure is 1 to 1.2 MPa, the main hydrogenation product is succinic anhydride (selectivity above 99.5%); when the reaction temperature is controlled above 200 °C and the reaction pressure is 5 MPa, the main hydrogenation product is γ-butyrolactone (selectivity above 95%); when the reaction temperature is controlled at 160 °C and the reaction pressure is 2.5 to 3 MPa, the hydrogenation product is a mixture of both (succinic anhydride selectivity 40 to 60%; γ-butyrolactone selectivity 40 to 60%).

[0020] The maleic anhydride solution is prepared by dissolving maleic anhydride in an organic solvent; the organic solvent is tetrahydrofuran, ethyl acetate, 1,4-dioxane, γ-butyrolactone, N,N-dimethylformamide or dimethyl succinate; preferably 1,4-dioxane. The mass space velocity of the maleic anhydride solution is 0.2 - 1 h -1 , and the hydrogen-oil ratio is 200 - 1000.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The catalyst of the present invention is applicable to the continuous hydrogenation of maleic anhydride to succinic anhydride and γ-butyrolactone in a fixed-bed reactor. By adjusting the reaction conditions, different product compositions can be controlled to achieve the continuous, highly active, and high-yield production of succinic anhydride and γ-butyrolactone, and it has good catalytic stability.

[0023] In the traditional impregnation method, the active component mainly exists in the form of nickel nitrate, and its molecular structure is relatively small, which is prone to crystallization and agglomeration during the drying and calcination processes. Therefore, the prepared catalyst has a relatively large particle size, a small atomic utilization rate, and a low catalytic activity. In the citric acid complex impregnation method, the nickel precursor mainly exists in the form of a complex. During the drying and calcination processes, the nickel complex will play an isolation role. On the one hand, the citric acid complexing agent coats the nickel particles, which is conducive to their highly dispersion. On the other hand, the citric acid complexing agent acts as a reducing agent, which is conducive to the formation of metallic Ni 0 and further improves the hydrogenation activity of the catalyst.

[0024] The maleic anhydride hydrogenation catalyst prepared by the present invention not only has a maleic anhydride conversion rate as high as 99.9% during the batch reaction in a high-pressure reactor, and still has a high conversion rate and selectivity after being continuously applied ten times, but also has a conversion rate still as high as over 99% after continuously reacting in a fixed bed for 500 h. Under low-temperature and low-pressure conditions, the selectivity of succinic anhydride is 99%, and under high-temperature and high-pressure conditions, the selectivity of γ-butyrolactone can reach 95%. The catalyst is simple to prepare, has excellent reaction activity, a long service life, and a high equipment utilization rate, which is conducive to its application in industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 XRD pattern of the Ba-modified support in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will be further described in detail below with reference to examples:

[0027] Example 1

[0028] Add 2.9 g of Ba(NO3)2 to an appropriate amount of deionized water to prepare an equal-volume barium nitrate solution. Stir the prepared solution and add it to 50 g of an alumina support (specific surface area is 200 - 250 m 2 / g, pore volume is 0.5 - 0.8 cm 2 / g, with an average pore diameter of 6 - 10 nm and a water absorption rate of approximately 0.8), it was impregnated in a constant temperature water bath at 80 °C for 4 h, and fully stirred during impregnation to make the loading uniform. Then the fully impregnated catalyst was placed in an oven at 105 °C for constant temperature drying for 10 h, and then the dried catalyst was placed in a muffle furnace at 900 °C for programmed temperature roasting for 5 h. Then, 24.7 g of Ni(NO3)2·6H2O, 1.6 g of Ce(NO3)3·6H2O, and 8.1 g of citric acid were added to an appropriate amount of deionized water to prepare an equal - volume mixed solution, which was added to the catalyst after roasting before. It was impregnated for 12 h, dried in an oven at 105 °C for 10 h, and then placed in a muffle furnace at 500 °C for programmed temperature roasting for 4 h to obtain the finished catalyst A1. In catalyst A1, the Ni content is 10 wt% of the carrier, the content of the first auxiliary agent Ba is 3 wt% of the carrier, and the content of the second auxiliary agent Ce is 1 wt% of the carrier (theoretical content).

[0029] Example 2

[0030] 4.8 g of Ba(NO3)2 was added to an appropriate amount of deionized water to prepare an equal - volume barium nitrate solution. The prepared solution was stirred and added to 50 g of alumina carrier (the same as in Example 1), and impregnated in a constant temperature water bath at 80 °C for 4 h, and fully stirred during impregnation to make the loading uniform. Then the fully impregnated catalyst was placed in an oven at 105 °C for constant temperature drying for 10 h, and then the dried catalyst was placed in a muffle furnace at 900 °C for programmed temperature roasting for 5 h.

[0031] Figure 1 For the XRD pattern of the Ba - modified carrier prepared above, obvious characteristic peaks (19.60°, 21.84°, 28.28°, 34.32°, 61.5°, 74.3°, etc.) can be observed.

[0032] 37 g of Ni(NO3)2·6H2O, 4.7 g of Ce(NO3)3·6H2O, and 12.2 g of citric acid were added to an appropriate amount of deionized water to prepare an equal - volume mixed solution, which was added to the catalyst after roasting before. It was impregnated for 12 h, dried in the oven (the same method as above), and then placed in a muffle furnace at 500 °C for programmed temperature roasting for 4 h to obtain the finished catalyst A2. In catalyst A2, the Ni content is 15 wt% of the carrier, the content of the first auxiliary agent Ba is 5 wt% of the carrier, and the content of the second auxiliary agent Ce is 3 wt% of the carrier.

[0033] Example 3

[0034] 6.7 g of Ba(NO3)2 was added to an appropriate amount of deionized water to prepare a barium nitrate solution of equal volume. The prepared solution was simultaneously stirred and added to 50 g of an alumina support (the same as in Example 1). It was impregnated in a constant temperature water bath at 80 °C for 4 h, and was fully stirred during impregnation to ensure uniform loading. Then, the impregnated catalyst was placed in an oven at 105 °C for constant temperature drying for 10 h. Subsequently, the dried catalyst was placed in a muffle furnace at 900 °C and calcined with a programmed temperature increase for 5 h. 49.3 g of Ni(NO3)2·6H2O, 7.8 g of Ce(NO3)3·6H2O and 16.3 g of citric acid were added to an appropriate amount of deionized water to prepare a mixed solution of equal volume, which was then added to the catalyst after the previous calcination. It was impregnated for 12 h, dried in the oven (using the same method as above), and then placed in a muffle furnace at 500 °C and calcined with a programmed temperature increase for 4 h to obtain the finished catalyst A3. The Ni content in the catalyst was 20 wt% of the support, the content of the first promoter Ba was 7 wt% of the support, and the content of the second promoter Ce was 5 wt% of the support.

[0035] Comparative Example 1

[0036] Only 4.9 g of cerium carbonate was used to replace 4.7 g of Ce(NO3)3·6H2O, and 12.2 g of the complexing agent citric acid was used. Other conditions were the same as in Example 2 to obtain the comparative catalyst finished product B1. The Ni content in the catalyst was 15 wt% of the support, the content of the first promoter Ba was 5 wt% of the support, and the content of the second promoter Ce was 3 wt% of the support.

[0037] The cerium carbonate in Comparative Example 1 has a relatively poor solubility in water compared with cerium nitrate, resulting in a worse impregnation effect than nitrates. Moreover, the decomposition temperature of cerium carbonate is as high as about 800 °C, requiring a high calcination temperature. If the temperature is raised to 800 °C to decompose cerium carbonate, the active component nickel will react with the support at high temperature to form NIAl2O4, which is not easily reduced and has poor activity.

[0038] Comparative Example 2

[0039] Only 4.3 g of cerium sulfate was used to replace 4.7 g of Ce(NO3)3·6H2O, and 12.2 g of the complexing agent citric acid was used. Other conditions were the same as in Example 2 to obtain the comparative catalyst finished product B2. The Ni content in the catalyst was 15 wt% of the support, the content of the first promoter Ba was 5 wt% of the support, and the content of the second promoter Ce was 3 wt% of the support.

[0040] Comparative Example 3

[0041] Only 4.3 g of barium sulfate was used to replace 4.8 g of Ba(NO3)2. Other conditions were the same as in Example 2 to obtain the comparative catalyst finished product B3. The Ni content in the catalyst was 15 wt% of the support, the content of the first promoter Ba was 5 wt% of the support, and the content of the second promoter Ce was 3 wt% of the support.

[0042] Comparative Example 4

[0043] Only 3.6 g of barium carbonate was used to replace 4.8 g of Ba(NO3)2, and the other conditions were the same as in Example 2 to obtain the comparative catalyst product B4. The Ni content in the catalyst was 15 wt% of the support, the content of the first promoter Ba was 5 wt% of the support, and the content of the second promoter Ce was 3 wt% of the support.

[0044] Comparative Example 5

[0045] Only 26.5 g of citric acid was not added, and the other conditions were the same as in Example 2 to obtain the comparative catalyst product B5. The Ni content in the catalyst was 15 wt% of the support, the content of the first promoter Ba was 5 wt% of the support, and the content of the second promoter Ce was 3 wt% of the support.

[0046] Comparative Example 6

[0047] Only 4.8 g of Ba(NO3)2 was not added, and the other conditions were the same as in Example 2 to obtain the comparative catalyst product B6. The Ni content in the catalyst was 15 wt% of the support, and the content of the promoter Ce was 3 wt% of the support.

[0048] Comparative Example 7

[0049] Only 4.7 g of Ce(NO3)3·6H2O was not added, the complexing agent citric acid was 12.2 g, and the other conditions were the same as in Example 2 to obtain the comparative catalyst product B7. The Ni content in the catalyst was 15 wt% of the support, and the content of the promoter Ba was 5 wt% of the support.

[0050] Comparative Example 8

[0051] 6.7 g of Ba(NO3)2, 4.7 g of Ce(NO3)3·6H2O and 12.2 g of the complexing agent citric acid were not added, and the other conditions were the same as in Example 3 to obtain the comparative catalyst product B8. The Ni content in the catalyst was 15 wt% of the support.

[0052] Examples 4 - 12

[0053] 10 ml (with a mass of 7.2 g) of the catalyst was loaded into a fixed-bed reactor and reduced and activated with hydrogen in the fixed bed before the reaction. The reduction conditions were: at normal pressure, reduced at 450 °C for 2 h and then cooled to the reaction temperature. The reaction pressure was 0.2 - 6 MPa. The raw material was pumped into the fixed-bed reactor through a feed pump for continuous reaction, and the mass space velocity of maleic anhydride was 0.2 - 1 h -1 , and the hydrogen-oil ratio was 200 - 1000. The reaction outlet material was analyzed.

[0054] The reaction results of different examples are shown in Table 1 below:

[0055]

[0056] Comparative Example 13

[0057] The reaction conditions were the same as those in Example 7 and Example 9, except that the catalyst was changed to Comparative Catalyst B1. After reacting for 500 h, under low temperature and low pressure conditions, the maleic anhydride conversion rate was 94.2%, and the selectivity to succinic anhydride was 96.3%; under high temperature and high pressure conditions, the conversion rate of maleic anhydride was 95.5%, and the selectivity to γ-butyrolactone was 82%.

[0058] Comparative Example 14

[0059] The reaction conditions were the same as those in Example 7 and Example 9, except that the catalyst was changed to Comparative Catalyst B2. After reacting for 500 h, under low temperature and low pressure conditions, the maleic anhydride conversion rate was 95.6%, and the selectivity to succinic anhydride was 93.3%; under high temperature and high pressure conditions, the conversion rate of maleic anhydride was 96.3%, and the selectivity to γ-butyrolactone was 83.3%.

[0060] Comparative Example 15

[0061] The reaction conditions were the same as those in Example 7 and Example 9, except that the catalyst was changed to Comparative Catalyst B3. After reacting for 500 h, under low temperature and low pressure conditions, the maleic anhydride conversion rate was 95.2%, and the selectivity to succinic anhydride was 94.3%; under high temperature and high pressure conditions, the conversion rate of maleic anhydride was 96.2%, and the selectivity to γ-butyrolactone was 83.9%.

[0062] Comparative Example 16

[0063] The reaction conditions were the same as those in Example 7 and Example 9, except that the catalyst was changed to Comparative Catalyst B4. After reacting for 500 h, under low temperature and low pressure conditions, the maleic anhydride conversion rate was 95%, and the selectivity to succinic anhydride was 94.8%; under high temperature and high pressure conditions, the conversion rate of maleic anhydride was 96.6%, and the selectivity to γ-butyrolactone was 82.8%.

[0064] Comparative Example 17

[0065] The reaction conditions were the same as those in Example 7 and Example 9, except that the catalyst was changed to Comparative Catalyst B5. After reacting for 200 h, under low temperature and low pressure conditions, the maleic anhydride conversion rate was 90.6%, and the selectivity to succinic anhydride was 97.8%; under high temperature and high pressure conditions, the conversion rate of maleic anhydride was 96.2%, and the selectivity to γ-butyrolactone was 79%.

[0066] Comparative Example 18

[0067] The reaction conditions were the same as those in Example 7 and Example 9, except that the catalyst was changed to Comparative Catalyst B6. After reacting for 200 h, under low temperature and low pressure conditions, the maleic anhydride conversion rate was 91.6%, and the selectivity to succinic anhydride was 91.8%; under high temperature and high pressure conditions, the conversion rate of maleic anhydride was 94.2%, and the selectivity to γ-butyrolactone was 75.6%.

[0068] Comparative Example 19

[0069] The reaction conditions were the same as those in Example 7 and Example 9, except that the catalyst was changed to Comparative Catalyst B7. After reacting for 200 h, under low temperature and low pressure conditions, the maleic anhydride conversion rate was 84.6%, and the selectivity for succinic anhydride was 92.8%; under high temperature and high pressure conditions, the conversion rate of maleic anhydride was 90.3%, and the selectivity for γ-butyrolactone was 84.3%.

[0070] Comparative Example 20

[0071] The reaction conditions were the same as those in Example 7 and Example 9, except that the catalyst was changed to Comparative Catalyst B8. After reacting for 200 h, under low temperature and low pressure conditions, the maleic anhydride conversion rate was 73.6%, and the selectivity for succinic anhydride was 89.8%; under high temperature and high pressure conditions, the conversion rate of maleic anhydride was 81.2%, and the selectivity for γ-butyrolactone was 62.5%.

[0072] From the results of Examples 4 - 12, it can be seen that the catalyst prepared by this invention has excellent maleic anhydride conversion rate, succinic anhydride selectivity, γ-butyrolactone selectivity and excellent stability under both low temperature and low pressure and high temperature and high pressure reaction conditions; moreover, the co-production of two products can be realized on the same device by adjusting the reaction conditions, greatly improving the equipment utilization rate and reducing the equipment cost and production cost. From the results of Comparative Examples 17 - 20, it can be seen that with the addition of the modified additive and the complexing agent, the reaction activity, product selectivity and stability of the catalyst have been improved to a certain extent, and the problems of single hydrogenation product in the maleic anhydride hydrogenation reaction by traditional nickel-based catalysts, or when co-producing succinic anhydride and γ-butyrolactone, most of the products are succinic anhydride, and the product yield ratio cannot be adjusted and the yield is low are solved.

Claims

1. Application of a maleic anhydride hydrogenation catalyst, characterized in that: The catalyst is used for the hydrogenation of maleic anhydride to prepare succinic anhydride and / or γ-butyrolactone; The catalyst uses Al2O3 as the carrier, Ni as the active component, and adds the first modifying agent alkaline earth metal barium salt to form a BaAl2O4 spinel film on the surface of the Al2O3 carrier under the condition of high-temperature calcination, and then adds the second modifying agent rare earth metal to obtain a hydrogenation catalyst under a complexing agent; the nickel content in the catalyst is 5-20% of the mass of the carrier, the Ba content is 1-7% of the mass of the carrier, the Ce content is 1-5% of the mass of the carrier, and the rest is the carrier.

2. Use of the maleic anhydride hydrogenation catalyst according to claim 1, characterized in that: The specific preparation steps are as follows: (1) Weigh the dried Al2O3 as the carrier, impregnate the Al2O3 carrier with barium nitrate solution by the equal-volume impregnation method, and impregnate it in a constant-temperature water bath at 70-80°C for 1-5 h; dry it, and put the dried catalyst into a muffle furnace at 600-1000°C for programmed temperature rise and calcination for 3-8 h; (2) Add the catalyst calcined in step (1) to the prepared mixed solution of nickel salt, cerium nitrate and complexing agent for impregnation, dry the impregnated catalyst, and put the dried catalyst into a muffle furnace at 200-600°C for calcination for 2-6 hours.

3. Use of the maleic anhydride hydrogenation catalyst according to claim 2, characterized in that: The specific surface area of the Al2O3 support is 200 - 250 m 2 / g, the pore volume is 0.5 - 0.8 cm 2 / g, and the average pore diameter is 6 - 10 nm; the barium salt is one or more of barium nitrate, barium sulfate, barium chloride, barium carbonate, and barium acetate.

4. Use of the maleic anhydride hydrogenation catalyst according to claim 2, characterized in that: The nickel salt is one or more of nickel nitrate, nickel chloride, nickel oxalate, nickel acetate or nickel sulfate.

5. Use of the maleic anhydride hydrogenation catalyst according to claim 2, characterized in that: The complexing agent is one or more of citric acid, monoethanolamine, diethanolamine, ethylenediamine, acetylacetone.

6. The application of the maleic anhydride hydrogenation catalyst according to claim 2, wherein: The programmed temperature rise condition in step (2) means rising to the required calcination temperature at a heating rate of 2°C / min.

7. Use of the maleic anhydride hydrogenation catalyst according to claim 1, characterized in that: Load the catalyst into a fixed-bed reactor, reduce and activate it with hydrogen in the fixed bed before the reaction, and react the maleic anhydride solution with hydrogen under the action of the reduced and activated catalyst. Among them, when controlling the reaction temperature at 60°C and the reaction pressure at 1.2 MPa, the main hydrogenation product is succinic anhydride; when controlling the reaction temperature above 200°C and the reaction pressure at 5 MPa, the main hydrogenation product is γ-butyrolactone.

8. The application of the maleic anhydride hydrogenation catalyst according to claim 1, wherein: The maleic anhydride solution raw material is pumped into a fixed-bed reactor through a feed pump for continuous reaction, and the mass space velocity of the maleic anhydride solution is 0.2 - 1 h -1 , and the hydrogen-oil ratio is 200 - 1000.

9. Use of the maleic anhydride hydrogenation catalyst according to claim 1, characterized in that: The maleic anhydride solution is prepared by dissolving maleic anhydride in an organic solvent; the organic solvent is tetrahydrofuran, ethyl acetate, 1,4-dioxane, γ-butyrolactone, N,N-dimethylformamide or dimethyl succinate.

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