A catalyst for producing succinic anhydride by gas phase hydrogenation of maleic anhydride, a preparation method and application thereof

Abstract

The application provides a nanometer copper-based catalyst for producing succinic anhydride by directional hydrogenation of maleic anhydride, a preparation method of the catalyst, and a method and use for producing succinic anhydride by using the catalyst, the catalyst comprising: a hydrogenation component copper and a silica carrier, wherein the content of the hydrogenation component copper is 4.5-40 wt%, the content of the carrier is 60-95.5 wt%, and the particle size of the catalyst is 0.4 mm-15 mm. The catalyst can realize selective hydrogenation reaction under normal pressure and gas phase conditions, and compared with liquid phase hydrogenation, the process conditions are more conducive to industrial production. Meanwhile, the catalyst can realize selective hydrogenation of C=C double bonds of maleic anhydride, the selectivity of hydrogenolysis byproducts of C=O groups is low, and the selectivity of the target product succinic anhydride can be realized to be more than 96%.

Description

Technical Field

[0001] This invention belongs to the field of chemical engineering and relates to a catalyst for the production of succinic anhydride from maleic anhydride, specifically a nano-copper-based catalyst that utilizes the gas-phase hydrogenation of maleic anhydride to produce succinic anhydride. Background Technology

[0002] Succinic anhydride, also known as succinic anhydride or SA for short, is an important chemical intermediate widely used in food additives as a flavoring agent in soy sauce, sake, and beverages. It is also used as a raw material in pharmaceuticals, pesticides, and dyes. Succinic anhydride and its hydrolysis product, succinic acid, can be polycondensed with butanediol to prepare high-performance biodegradable plastic polybutylene succinate (PBS). The PBS structural units contain easily hydrolyzed ester groups, which, under conditions such as composting and contact with specific microorganisms, are easily decomposed and metabolized by various microorganisms in nature or enzymes in animals and plants, ultimately forming CO2 and H2O, thus avoiding environmental pollution.

[0003] With increasing environmental awareness and the gradual implementation of my country's "plastic ban," biodegradable materials are being widely adopted, especially PBS-based biodegradable plastics, which offer superior performance and abundant raw material sources. However, my country's succinic anhydride production technology is immature and has not yet achieved large-scale industrial production, while its maleic anhydride (maleic anhydride) production technology is mature and has achieved large-scale industrial production. Therefore, producing succinic anhydride from maleic anhydride via directed hydrogenation is considered the best process route to meet the future demand for key monomers in biodegradable plastics, with broad market prospects. However, currently, Chinese companies mainly use the energy-intensive maleic anhydride electrolysis method to produce succinic anhydride, which is complex, has low capacity, and high production costs.

[0004] Because both maleic anhydride and succinic anhydride have high melting points and are solids at room temperature, most currently developed processes for the catalytic hydrogenation of maleic anhydride to produce succinic anhydride employ a liquid-phase solvent method to avoid reactor pipe blockage. This involves dissolving maleic anhydride in an organic solvent and then performing hydrogenation-separation to obtain succinic anhydride. For example, Chinese patent CN1453066A uses a nickel-based catalyst and THF, toluene, and 1,4-dioxane as solvents to directly hydrogenate succinic anhydride at a hydrogen pressure of 0.5–3 MPa and a temperature of 120–180 °C. This patent uses a nickel-based catalyst and can achieve a maleic anhydride conversion rate greater than 99.7% and a succinic anhydride selectivity greater than 99%. However, the use of solvents such as THF, toluene, and 1,4-dioxane necessitates the provision of a pressure vessel as a reactor, significantly increasing production costs. Chinese patent CN102311332B uses γ-butyrolactone as a solvent and a 5wt% Pd-2wt% Fe / C catalyst to continuously react for 300 hours in a fixed-bed reactor at 70℃ and 1.5MPa hydrogen pressure, achieving a 100% maleic anhydride conversion and a 99.2% succinic anhydride selectivity. While this patent uses an Fe / C catalyst to achieve efficient maleic anhydride conversion, it still employs γ-butyrolactone as a solvent, resulting in a lower temperature and difficulty in controlling heat dissipation during the reaction. Chinese patents CN105597742A and CN105801536B respectively disclose catalysts for the liquid-phase hydrogenation of maleic anhydride to succinic anhydride and a two-stage low-temperature, low-pressure liquid-phase hydrogenation method for preparing succinic anhydride from maleic anhydride. Both methods involve connecting two hydrogenation reactors in series. Maleic anhydride, solvent, and hydrogen are fed into a first-stage reactor for partial hydrogenation at 40°C and 0.2–2.0 MPa, and then into a second-stage reactor for complete hydrogenation at 60–120°C and 0.2–2.0 MPa. Both stages use supported Pd catalysts, and the solvents used are dimethyl succinate, diethyl succinate, ethyl acetate, butyl acetate, and γ-butyrolactone. While this patent utilizes a Pd catalyst for selective hydrogenation of the double bonds in maleic anhydride, it employs large amounts of dimethyl succinate, diethyl succinate, ethyl acetate, butyl acetate, and γ-butyrolactone as solvents, resulting in high costs. Chinese patent CN101735182A discloses a process for the continuous production of succinic anhydride from maleic anhydride by hydrogenation, employing a supported nickel catalyst, a hydrogen pressure of 0.9–10.0 MPa, and a feed liquid hourly space velocity of 0.13–0.16 h⁻¹. -1The maleic anhydride solution is preheated to 35–60°C, with a concentration of 0.04–0.08 g / ml. The solvent is any one of tetrahydrofuran, acetone, 1,4-dioxane, benzene, toluene, γ-butyrolactone, propyl ether, isopropyl ether, butyl ether, isobutyl ether, ethyl acetate, isopropyl acetate, isoamyl acetate, diethyl succinate, dimethyl succinate, etc. The yield of succinic anhydride is higher than 97.5%. This patent uses a nickel-based catalyst, which can effectively improve the conversion rate and selectivity of maleic anhydride. However, the reaction pressure is high, the temperature is low, and the exothermic reaction temperature is difficult to control. It still cannot get rid of the high cost problem caused by the use of solvents. Chinese patent CN113332999A discloses a catalyst for the hydrogenation of maleic anhydride to prepare succinic anhydride. The catalyst contains a support and a metal component supported on the support. The metal component includes a first active center component, a second active center component, a first auxiliary agent, and a second auxiliary agent. The first active center component is one or any of Pd, Ru, Pt, or Au. The second active center component is one or any of Cu, Ni, Co, and Cr. The first auxiliary agent is one or any of Zn, Mo, W, and Fe. The second auxiliary agent is one or two of La or Ce. The support is one or any of activated carbon, alumina, silica, titanium dioxide, or aluminosilicate molecular sieve. However, the catalyst in this patent requires the use of various precious metal additives, making it extremely expensive in practical use. On the other hand, when the reaction temperature increases (for example, above 200°C), the selectivity of the catalyst for succinic anhydride decreases significantly, failing to specifically improve the selectivity of succinic anhydride, while the selectivity of 1,4-butanediol increases. In practical industrial applications, it is impossible to effectively control the temperature rise caused by the exothermic reaction, which in turn leads to a decrease in the selectivity of succinic anhydride. In addition, the reaction in this patent needs to be carried out under pressure of 0.5-4 MPa, further increasing the production cost.

[0005] To address the problems existing in the above-mentioned technologies, there is an urgent need to develop corresponding key and efficient catalysts for the solventless directed hydrogenation of maleic anhydride to produce succinic anhydride, so as to further improve the selectivity of succinic anhydride and reduce production costs. Summary of the Invention

[0006] The purpose of this invention is to provide a nano-copper-based catalyst for the production of succinic anhydride by directional hydrogenation of maleic anhydride and its preparation method. The catalyst of this invention can achieve selective hydrogenation of the C=C double bond of maleic anhydride, with low selectivity for C=O group hydrogenation by-products and a selectivity of up to 96.4% for the target product succinic anhydride.

[0007] In a first aspect, the present invention provides a nano-copper-based catalyst for producing succinic anhydride by directional hydrogenation of maleic anhydride. The catalyst comprises: a hydrogenation component of copper and a silica support, wherein the content of the hydrogenation component of copper is 4.5-40 wt%, the content of the support is 60-95.5 wt%, and the catalyst particle size is 0.4 mm-15 mm. Preferably, the catalyst further comprises a metal oxide promoter in a content of 4.5-13.5 wt%, wherein the metal oxide is selected from one or more oxides of Pt, Pd, Co, Ni, Mg, Ca, Zn, and Al.

[0008] Secondly, the present invention provides a method for preparing the above-mentioned catalyst, wherein the preparation method includes:

[0009] (1) Prepare a water-soluble salt solution of metallic copper and add urea to dissolve it to obtain solution I;

[0010] (2) Add the alkaline silica sol to the above solution I and mix well to obtain solution II;

[0011] (3) The above solution II was transferred to a closed reaction vessel for hydrolysis to obtain the catalyst precursor;

[0012] (4) After crystallizing, filtering, drying and calcining the catalyst precursor, a nano-copper-based catalyst is obtained.

[0013] Preferably, the copper-based catalyst is impregnated with a water-soluble salt solution of a metal oxide auxiliary to obtain a highly efficient nano-copper-based catalyst.

[0014] Thirdly, the present invention provides a method for producing succinic anhydride, wherein the method includes the following steps: gas-phase hydrogenation of maleic anhydride using the above-mentioned catalyst under normal pressure.

[0015] Fourthly, the present invention provides the use of the above-mentioned catalyst for catalyzing the gas-phase hydrogenation of maleic anhydride at atmospheric pressure to produce succinic anhydride.

[0016] Fifthly, the present invention provides the use of the above-mentioned catalyst for improving the succinic anhydride conversion and / or selectivity in the production of succinic anhydride by gas-phase hydrogenation of maleic anhydride at atmospheric pressure, preferably, the succinic anhydride selectivity is 90% or more.

[0017] The present invention has the following beneficial effects:

[0018] (1) The nano-copper-based catalyst developed in this invention can achieve selective hydrogenation of maleic anhydride C=C double bond, and significantly reduce the selectivity of C=O group hydrogenation hydrogenolysis byproducts;

[0019] (2) The nano-copper-based catalyst developed in this invention is prepared by the homogeneous-crystallization method. It is a nano-tubular copper silicate catalyst with a special nano-layer tubular structure. This structure has high dispersibility and strong metal interaction, which is conducive to the adhesion of metal additives and the formation of interaction, thus avoiding metal loss.

[0020] (3) The nano-copper-based catalyst developed in this invention has high activity and can carry out selective hydrogenation reaction under normal pressure and gas phase conditions. Since the catalyst of this invention is more suitable for the hydrogenation of maleic anhydride to produce succinic anhydride under normal pressure and gas phase conditions, the process conditions are more favorable for industrial production compared with liquid phase hydrogenation.

[0021] (4) The catalyst of the present invention uses urea as a nitrogen source and is prepared by uniform precipitation-urea crystallization method, and then optionally by impregnation with metal additives. Urea is a low-cost nitrogen source and is more conducive to the production of the above-mentioned special nano-layer tubular structure. After complexing with copper, excess urea will volatilize during the crystallization process, and the remaining nitrogen will be lost in the form of gas during the calcination stage, without affecting the catalyst itself. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a copper-based catalyst according to one embodiment of the present invention. Detailed Implementation

[0023] The specific embodiments of the present invention will be described in detail below. The specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0024] In this invention, the term "atmospheric pressure" refers to 1 standard atmosphere.

[0025] In some embodiments, the present invention provides a nano-copper-based catalyst for producing succinic anhydride by directed hydrogenation of maleic anhydride, the catalyst comprising: a hydrogenation component copper and a silica support, wherein the content of the hydrogenation component copper is 4.5-40 wt%, the content of the support is 60-95.5 wt%, and the catalyst particle size is 0.4 mm-15 mm, for example 0.425 mm-0.850 mm.

[0026] In some preferred embodiments, the catalyst further comprises 4.5-13.5 wt% of a metal oxide promoter, which may be selected from one or more oxides of Pt, Pd, Co, Ni, Mg, Ca, Zn, and Al, and is preferably one or more of NiO, MgO, Al2O3, and ZnO.

[0027] In some further preferred embodiments, the catalyst contains 10wt%-35wt% copper (e.g., 10wt%-30wt% or 30wt%-35wt%), the metal oxide additive loading is 5wt%-10wt%, and the support content is 60wt%-90wt%.

[0028] In other embodiments, the present invention provides a method for preparing a nano-copper-based catalyst using the directional hydrogenation of maleic anhydride to succinic anhydride, the method comprising:

[0029] (1) Prepare a water-soluble salt solution of metallic copper and add urea to dissolve it to obtain solution I;

[0030] (2) Add the alkaline silica sol to the above solution I and mix well to obtain solution II;

[0031] (3) The above solution II was transferred to a closed reaction vessel for hydrolysis to obtain the catalyst precursor;

[0032] (4) After crystallizing, filtering, drying and calcining the catalyst precursor, a nano-copper-based catalyst is obtained.

[0033] In some preferred embodiments, in step (1), the water-soluble salt of metallic copper is one or more of copper nitrate and copper salt of copper sulfate.

[0034] In some preferred embodiments, in step (1), the concentration of the water-soluble salt solution of metallic copper is 1 mol / L to 2 mol / L.

[0035] In some preferred embodiments, in step (1), the urea is in the form of an aqueous urea solution with a concentration of 1 mol / L to 2 mol / L, and the mass ratio of the aqueous urea solution to the water-soluble salt solution of metallic copper is (2-50):1, preferably (2-20):1, for example (3-15):1 or (3-12):1.

[0036] In some preferred embodiments, in step (2), the alkaline silica sol is an aqueous dispersion with a silica concentration of 25wt%-35wt%.

[0037] In some preferred embodiments, in step (2), the mass ratio of the alkaline silica sol to the solution I is 1:(1-50), preferably 1:(1-15), for example 1:(1-10).

[0038] In some preferred embodiments, in step (3), the hydrolysis conditions are: temperature 50-70℃ (e.g., 65-70℃), pressure at atmospheric pressure, and hydrolysis time of 12h-24h.

[0039] In some preferred embodiments, in step (4), the crystallization conditions are: temperature 150-200℃ (e.g., 160-200℃) and time 12h-24h.

[0040] In some preferred embodiments, in step (4), the filtering is a commonly used filtering method in the art.

[0041] In some preferred embodiments, in step (4), the drying conditions are: a drying temperature of 60-120°C (e.g., 110-120°C) and a drying time of 8-24 hours.

[0042] In some preferred embodiments, in step (4), the calcination conditions are: temperature 350-500℃ (e.g., 450-500℃) and time 4-8h.

[0043] In some preferred embodiments, the method further includes step (5): impregnating the above copper-based catalyst with a water-soluble salt solution of a metal oxide auxiliary to obtain a highly efficient nano-copper-based catalyst.

[0044] In some preferred embodiments, in step (5), the metal oxide additive is one or more of NiO, MgO, Al2O3, and ZnO, and the water-soluble salt solution used for impregnation is one or more of nickel nitrate, nickel sulfate, magnesium nitrate, magnesium sulfate, aluminum nitrate, aluminum sulfate, zinc nitrate, and zinc sulfate.

[0045] In some preferred embodiments, in step (5), the metal oxide additive is nickel oxide, and the water-soluble salt solution used for impregnation is one or more nickel salts such as nickel nitrate.

[0046] In other embodiments, the present invention provides a method for producing succinic anhydride, wherein the method includes the following steps: gas-phase hydrogenation of maleic anhydride using the above-mentioned catalyst at atmospheric pressure.

[0047] In some preferred embodiments, the gas-phase hydrogenation is carried out in a fixed-bed reactor, preferably under the following conditions: a reaction temperature of 250-290°C (e.g., 270°C-290°C), a hydrogen flow rate of 600-1000 mL / min (e.g., 900 mL / min-1000 mL / min), and a maleic anhydride flow rate of 0.01-0.1 mL / min (e.g., 0.04-0.1 mL / min).

[0048] In other embodiments, the present invention provides the use of the above-described catalyst for catalyzing the gas-phase hydrogenation of maleic anhydride at atmospheric pressure to produce succinic anhydride.

[0049] In other embodiments, the present invention provides the use of the above-described catalyst for improving the succinic anhydride conversion and / or selectivity in the production of succinic anhydride by gas-phase hydrogenation of maleic anhydride at atmospheric pressure, preferably, the succinic anhydride selectivity being 90% or more.

[0050] Next, exemplary embodiments of the present invention will be described using the following numbered paragraphs:

[0051] 1. A nano-copper-based catalyst for producing succinic anhydride by directional hydrogenation of maleic anhydride, the catalyst comprising: a hydrogenation component copper and a silica support, wherein the content of the hydrogenation component copper is 4.5-40 wt%, the content of the support is 60-95.5 wt%, and the catalyst particle size is 0.4 mm-15 mm.

[0052] 2. The catalyst as described in paragraph 1, wherein the catalyst further comprises 4.5-13.5 wt% of a metal oxide promoter.

[0053] 3. The catalyst as described in paragraph 2, wherein the metal oxide promoter is selected from one or more oxides of Pt, Pd, Co, Ni, Mg, Ca, Zn, and Al.

[0054] 4. The catalyst as described in paragraph 3, wherein the metal oxide promoter is selected from one or more of NiO, MgO, Al2O3, and ZnO.

[0055] 5. The catalyst as described in any of paragraphs 1-4, wherein the content of the hydrogenation component copper in the catalyst is 10-35 wt%.

[0056] 6. The catalyst as described in any of paragraphs 1-5, wherein the content of the metal oxide promoter in the catalyst is 5-10 wt%.

[0057] 7. The catalyst as described in any of paragraphs 1-6, wherein the content of the support in the catalyst is 60-90 wt%.

[0058] 8. A method for preparing a nano-copper-based catalyst for the production of succinic anhydride using directional hydrogenation of maleic anhydride, wherein the method comprises:

[0059] (1) Prepare a water-soluble salt solution of metallic copper and add urea to dissolve it to obtain solution I;

[0060] (2) Add the alkaline silica sol to the above solution I and mix well to obtain solution II;

[0061] (3) The above solution II was transferred to a closed reaction vessel for hydrolysis to obtain the catalyst precursor;

[0062] (4) After crystallizing, filtering, drying and calcining the catalyst precursor, a nano-copper-based catalyst is obtained.

[0063] 9. The method as described in paragraph 8, wherein, in step (1), the water-soluble salt of metallic copper is one or more of copper nitrate and copper salt of copper sulfate.

[0064] 10. The method as described in paragraph 8 or 9, wherein, in step (1), the concentration of the water-soluble salt solution of metallic copper is 1 mol / L to 2 mol / L.

[0065] 11. The method as described in any of paragraphs 8-10, wherein, in step (1), the urea is in the form of an aqueous urea solution with a concentration of 1 mol / L to 2 mol / L.

[0066] 12. The method as described in paragraph 11, wherein the mass ratio of the urea aqueous solution to the water-soluble salt solution of metallic copper is (2-50):1.

[0067] 13. The method described in any of paragraphs 8-12, wherein, in step (2), the alkaline silica sol is an aqueous dispersion with a silica concentration of 25wt%-35wt%.

[0068] 14. The method described in any of paragraphs 8-13, wherein in step (2), the mass ratio of the alkaline silica sol to the solution I is 1:(1-50).

[0069] 15. The method described in any of paragraphs 8-14, wherein in step (3), the conditions for hydrolysis are: hydrolysis temperature 50-70℃, pressure at atmospheric pressure, and hydrolysis time 12h-24h.

[0070] 16. The method described in any of paragraphs 8-15, wherein in step (4), the crystallization conditions are: crystallization temperature 150-200℃, crystallization time 12h-24h.

[0071] 17. The method described in any of paragraphs 8-16, wherein in step (4), the drying conditions are: drying temperature 60-120℃, drying time 8-24h.

[0072] 18. The method described in any of paragraphs 8-17, wherein in step (4), the calcination conditions are: calcination temperature 350-500℃, calcination time 4-8h.

[0073] 19. The method as described in any of paragraphs 8-18, wherein the method further comprises step (5): impregnating the copper-based catalyst with a water-soluble salt solution of a metal oxide auxiliary.

[0074] 20. The method as described in paragraph 19, wherein in step (5), the metal oxide additive is one or more of NiO, MgO, Al2O3, and ZnO, and the water-soluble salt solution used for impregnation is one or more of nickel nitrate, nickel sulfate, magnesium nitrate, magnesium sulfate, aluminum nitrate, aluminum sulfate, zinc nitrate, and zinc sulfate.

[0075] 21. The method as described in paragraph 20, wherein in step (5), the metal oxide additive is nickel oxide, and the water-soluble salt solution used for impregnation is one or more nickel salts.

[0076] 22. The method as described in paragraph 21, wherein the nickel salt is nickel nitrate and / or nickel sulfate.

[0077] 23. A method for producing succinic anhydride, wherein the method comprises the step of: gas-phase hydrogenation of maleic anhydride at atmospheric pressure using a catalyst as described in any of paragraphs 1-7 or a catalyst prepared by the method as described in any of paragraphs 8-22.

[0078] 24. The method as described in paragraph 23, wherein the gas-phase hydrogenation is carried out in a fixed-bed reactor.

[0079] 25. The method as described in paragraph 23 or 24, wherein the conditions for gas-phase hydrogenation are: reaction temperature 250-290℃, hydrogen flow rate 600-1000 mL / min, and maleic anhydride flow rate 0.01-0.1 mL / min.

[0080] 26. The use of a catalyst as described in any of paragraphs 1-7, or a catalyst prepared by the method described in any of paragraphs 8-25, for the catalytic gas-phase hydrogenation of maleic anhydride at atmospheric pressure to produce succinic anhydride.

[0081] 27. The use of catalysts as described in any of paragraphs 1-7, or catalysts prepared by methods as described in any of paragraphs 8-25, for improving the succinic anhydride conversion and / or selectivity in the production of succinic anhydride by gas-phase hydrogenation of maleic anhydride at atmospheric pressure.

[0082] 28. The use as described in paragraph 27, wherein the succinic anhydride has a selectivity of 90% or more.

[0083] The catalyst of this invention is suitable for atmospheric pressure reaction conditions, and can react at 270°C in the gas phase. In industrial production, it does not require a high-cost pressure reaction vessel. Compared with liquid phase reaction conditions, gas phase reaction can more easily remove excess heat generated in the reaction, which is beneficial to improving the selectivity of succinic anhydride and reducing the generation of by-products.

[0084] This invention uses urea as a complexing nitrogen source, which is less expensive; at the same time, the additives use Ni, which is less expensive than platinum and palladium in the prior art.

[0085] Example

[0086] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples and comparative examples are commercially available.

[0087] In the following examples and comparative examples, copper nitrate, nickel nitrate, silica sol, urea, maleic anhydride, etc., were all commercially available, and the 20-40 mesh quartz sand was also commercially available. For experimental methods in the following examples and comparative examples where specific conditions are not specified, conventional methods and conditions should be followed, or the product instructions should be consulted.

[0088] In the following processes, both the comparative and experimental examples were conducted in a conventional fixed-bed reactor. The reaction liquid products were analyzed using an Agilent 6890 with an AB-InoWax (30m × 0.32mm × 0.5μm) test column, and each analyte was quantified using the external standard method.

[0089] Comparative Example 1

[0090] Catalyst preparation: 370 g of a 1 mol / L copper nitrate aqueous solution and 120 g of a 1 mol / L zinc nitrate aqueous solution were prepared, along with 1 L of a 1 mol / L sodium carbonate aqueous solution as a precipitant. The mixture was then co-precipitated at 65 °C under co-current conditions, with the pH controlled at 7.5. After precipitation, the mixture was aged for 30 minutes. The resulting mixed solution was filtered to obtain a filter cake, which was dried in an oven at 110 °C for 24 h, calcined in a muffle furnace at 450 °C for 6 h, and then pressed and pulverized to obtain a Cu-ZnO catalyst with a copper content of 50% and a ZnO support content of 50%.

[0091] 10 mL of the above catalyst was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set at 270 °C, the reaction pressure at atmospheric pressure, and the hydrogen flow rate at 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.03 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0092] Example 1

[0093] Catalyst preparation: 126g of a 1mol / L copper nitrate aqueous solution was prepared, and then 1500g of a 2mol / L urea solution and 300g of a 30% alkaline silica sol were added and mixed thoroughly. The mixture was then transferred to a reactor and heated to 65℃ for hydrolysis for 24 hours, followed by crystallization at 160℃ for 24 hours. The resulting solution was filtered to obtain a filter cake, which was dried in an oven at 110℃ for 24 hours and calcined in a muffle furnace at 450℃ for 6 hours. After pressing and pulverizing, a copper-based catalyst with a copper content of 10% and a silica support content of 90% was obtained.

[0094] 10 mL of CuO / SiO2-10 catalyst (20-40 mesh) was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set to 270 °C, the reaction pressure to atmospheric pressure, and the hydrogen flow rate to 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.04 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0095] Example 2

[0096] Prepare 251g of a 1mol / L copper nitrate aqueous solution, then add 2000g of 1mol / L urea and 266g of 30% alkaline silica sol and mix thoroughly. Transfer the mixture to a reactor and heat to 65℃ for hydrolysis for 24 hours, then to 160℃ for crystallization for 24 hours. Filter the resulting solution to obtain a filter cake, which is dried in an oven at 110℃ for 24 hours and calcined in a muffle furnace at 450℃ for 6 hours. After pressing and pulverizing, obtain a copper-based catalyst with a copper content of 20% and a silica support content of 80%.

[0097] 10 mL of CuO / SiO2-20 catalyst (20-40 mesh) was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set to 270 °C, the reaction pressure to atmospheric pressure, and the hydrogen flow rate to 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.04 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0098] Example 3

[0099] Prepare 377g of a 1mol / L copper nitrate aqueous solution, then add 1300g of 1.2mol / L urea and 233g of 30% alkaline silica sol and mix thoroughly. The mixture is then transferred to a reactor and heated to 65℃ for hydrolysis for 24 hours, followed by crystallization at 160℃ for 24 hours. The resulting solution is filtered to obtain a filter cake, which is dried in an oven at 110℃ for 24 hours and calcined in a muffle furnace at 450℃ for 6 hours. After pressing and pulverizing, a copper-based catalyst with a copper content of 30% and a silica support of 70% is obtained.

[0100] 10 mL of CuO / SiO2-30 catalyst (20-40 mesh) was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set to 270 °C, the reaction pressure to atmospheric pressure, and the hydrogen flow rate to 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.04 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0101] Example 4

[0102] Prepare 502g of a 1mol / L copper nitrate aqueous solution, then add 1800g of 1.5mol / L urea and 200g of 30% alkaline silica sol and mix thoroughly. Transfer the mixture to a reactor and heat to 65℃ for hydrolysis for 24 hours, then to 160℃ for crystallization for 24 hours. Filter the resulting solution to obtain a filter cake, which is dried in an oven at 110℃ for 24 hours and calcined in a muffle furnace at 450℃ for 6 hours. After pressing and pulverizing, obtain a copper-based catalyst with a copper content of 40% and a silica support content of 60%.

[0103] 10 mL of CuO / SiO2-40 catalyst (20-40 mesh) was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set to 270 °C, the reaction pressure to atmospheric pressure, and the hydrogen flow rate to 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.04 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0104] Example 5

[0105] Prepare 502g of a 1mol / L copper nitrate aqueous solution, then add 1800g of 1.5mol / L urea and 200g of 30% alkaline silica sol and mix thoroughly. Transfer the mixture to a reactor and heat to 65℃ for hydrolysis for 24 hours, followed by crystallization at 160℃ for 24 hours. Filter the resulting solution to obtain a filter cake, which is then dried in an oven at 110℃ for 24 hours, calcined in a muffle furnace at 450℃ for 6 hours, impregnated with 67mL of a 1mol / L nickel nitrate solution for 24 hours, dried in an oven at 110℃ for 24 hours, and calcined in a muffle furnace at 450℃ for 6 hours. After tableting and pulverization, a high-efficiency copper-based catalyst with a copper content of 35%, a nickel oxide content of 5%, and a silica content of 60% is obtained.

[0106] 10 mL of Ni-CuO / SiO2-40-5 catalyst (20-40 mesh) was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set to 270 °C, the reaction pressure to atmospheric pressure, and the hydrogen flow rate to 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.05 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0107] Example 6

[0108] 502 g of a 1 mol / L copper nitrate aqueous solution was prepared, and then 1800 g of a 1.5 mol / L urea solution and 200 g of a 30% alkaline silica sol were added and mixed thoroughly. The mixture was then transferred to a reactor and heated to 65°C for hydrolysis for 24 hours, followed by crystallization at 160°C for 24 hours. The resulting solution was filtered to obtain a filter cake, which was dried in an oven at 110°C for 24 hours, calcined in a muffle furnace at 450°C for 6 hours, and then impregnated with 95 mL of a 1 mol / L nickel nitrate solution for 24 hours, dried in an oven at 110°C for 24 hours, and calcined in a muffle furnace at 450°C for 6 hours. After tableting and pulverization, a high-efficiency copper-based catalyst with a copper content of 33%, a nickel oxide content of 7%, and a silica content of 60% was obtained.

[0109] 10 mL of Ni-CuO / SiO2-40-7 catalyst (20-40 mesh) was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set at 270 °C, the reaction pressure at atmospheric pressure, and the hydrogen flow rate at 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.05 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0110] Example 7

[0111] 502 g of a 1 mol / L copper nitrate aqueous solution was prepared, and then 1800 g of a 1.5 mol / L urea solution and 200 g of a 30% alkaline silica sol were added and mixed thoroughly. The mixture was then transferred to a reactor and heated to 65°C for hydrolysis for 24 hours, followed by crystallization at 160°C for 24 hours. The resulting solution was filtered to obtain a filter cake, which was dried in an oven at 110°C for 24 hours, calcined in a muffle furnace at 450°C for 6 hours, and then impregnated with 107 mL of a 1 mol / L nickel nitrate solution for 24 hours, dried in an oven at 110°C for 24 hours, and calcined in a muffle furnace at 450°C for 6 hours. After tableting and pulverization, a high-efficiency copper-based catalyst with a copper content of 32%, a nickel oxide content of 8%, and a silica content of 60% was obtained.

[0112] 10 mL of Ni-CuO / SiO2-40-8 catalyst (20-40 mesh) was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set to 270 °C, the reaction pressure to atmospheric pressure, and the hydrogen flow rate to 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.05 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0113] Example 8

[0114] Prepare 502g of a 1mol / L copper nitrate aqueous solution, then add 1800g of 1.5mol / L urea and 200g of 30% alkaline silica sol and mix thoroughly. Transfer the mixture to a reactor and heat to 65℃ for hydrolysis for 24 hours, followed by crystallization at 160℃ for 24 hours. Filter the resulting solution to obtain a filter cake, which is then dried in an oven at 110℃ for 24 hours, calcined in a muffle furnace at 450℃ for 6 hours, impregnated with 134mL of a 1mol / L nickel nitrate solution for 24 hours, dried in an oven at 110℃ for 24 hours, and calcined in a muffle furnace at 450℃ for 6 hours. After tableting and pulverization, a high-efficiency copper-based catalyst with a copper content of 30%, a nickel oxide content of 10%, and a silica content of 60% is obtained.

[0115] 10 mL of Ni-CuO / SiO2-40-10 catalyst (20-40 mesh) was weighed and loaded into a fixed-bed reactor with a diameter of 12 mm and a height of 1000 mm. Quartz sand was packed above and below the catalyst. The reaction temperature was set to 270 °C, the reaction pressure to atmospheric pressure, and the hydrogen flow rate to 900 mL / min. After the hydrogenation reaction began, maleic anhydride was introduced into the fixed-bed reactor at a flow rate of 0.05 mL / min. After 24 hours of reaction operation, samples were taken from the gas-liquid separator for analysis. The reaction results are shown in Table 1.

[0116] Table 1 Results of the directed catalytic hydrogenation of maleic anhydride to prepare succinic anhydride

[0117]

[0118]

[0119] Reaction conversion rate (%) = (moles of reactants converted / moles of reactants in the starting material) × 100%. Product selectivity (%) = (moles of a certain product generated / moles of reactants converted) × 100%. Other products include propanol, butanol, propionic acid, butyric acid, etc.

Claims

1. A nano-copper-based catalyst for the directional hydrogenation of maleic anhydride to produce succinic anhydride at a reaction temperature of 250-290℃, the catalyst comprising: a hydrogenation component of copper and a silica support, wherein, The hydrogenation component has a copper content of 4.5-40 wt%, a support content of 60-95.5 wt%, and a catalyst particle size of 0.4 mm-15 mm. The catalyst uses urea as a nitrogen source and is prepared by a uniform precipitation-urea crystallization method, and the catalyst has a nano-layered tubular structure. The catalyst is prepared by a method comprising the following steps: (1) Prepare a water-soluble salt solution of metallic copper and add urea to dissolve it to obtain solution I; (2) Add the alkaline silica sol to the above solution I and mix well to obtain solution II; (3) The above solution II was transferred to a closed reactor for hydrolysis to obtain the catalyst precursor; (4) After crystallizing, filtering, drying and calcining the catalyst precursor, a nano-copper-based catalyst is obtained.

2. The catalyst as claimed in claim 1, wherein, The catalyst also contains 4.5-13.5 wt% of metal oxide additives.

3. The catalyst as described in claim 2, wherein, The metal oxide additive is selected from one or more oxides of Pt, Pd, Co, Ni, Mg, Ca, Zn, and Al.

4. The catalyst as described in claim 3, wherein, The metal oxide additive is selected from one or more of NiO, MgO, Al2O3, and ZnO.

5. The catalyst according to any one of claims 1-4, wherein, In the catalyst, the content of the hydrogenation component copper is 10-35 wt%.

6. The catalyst according to any one of claims 2-4, wherein, In the catalyst, the content of the metal oxide promoter is 5-10 wt%.

7. The catalyst according to any one of claims 1-4, wherein, In the catalyst, the content of the support is 60-90 wt%.

8. A method for preparing a catalyst according to any one of claims 1-7, wherein, The method includes: (1) Prepare a water-soluble salt solution of metallic copper and add urea to dissolve it to obtain solution I; (2) Add the alkaline silica sol to the above solution I and mix well to obtain solution II; (3) The above solution II was transferred to a closed reactor for hydrolysis to obtain the catalyst precursor; (4) After crystallizing, filtering, drying and calcining the catalyst precursor, a nano-copper-based catalyst is obtained.

9. The method of claim 8, wherein, In step (1), the water-soluble salt of metallic copper is one or more of copper salts of copper nitrate and copper sulfate.

10. The method of claim 8 or 9, wherein, In step (1), the concentration of the water-soluble salt solution of metallic copper is 1 mol / L-2 mol / L.

11. The method of claim 8 or 9, wherein, In step (1), the urea is in the form of an aqueous urea solution with a concentration of 1 mol / L to 2 mol / L.

12. The method of claim 11, wherein, The mass ratio of the urea aqueous solution to the water-soluble salt solution of metallic copper is (2-50):

1.

13. The method of claim 8 or 9, wherein, In step (2), the alkaline silica sol is an aqueous dispersion with a silica concentration of 25wt%-35wt%.

14. The method of claim 8 or 9, wherein, In step (2), the mass ratio of the alkaline silica sol to solution I is 1:(1-50).

15. The method of claim 8 or 9, wherein, In step (3), the hydrolysis conditions are: hydrolysis temperature 50-70℃, pressure at atmospheric pressure, and hydrolysis time 12h-24h.

16. The method of claim 8 or 9, wherein, In step (4), the crystallization conditions are: crystallization temperature 150-200℃, crystallization time 12h-24h.

17. The method of claim 8 or 9, wherein, In step (4), the drying conditions are: drying temperature 60-120℃, drying time 8-24h.

18. The method of claim 8 or 9, wherein, In step (4), the calcination conditions are: calcination temperature 350-500℃, calcination time 4-8h.

19. The method of claim 8 or 9, wherein, The method further includes step (5): impregnating the copper-based catalyst with a water-soluble salt solution of a metal oxide additive.

20. The method of claim 19, wherein, In step (5), the metal oxide additive is one or more of NiO, MgO, Al2O3, and ZnO, and the water-soluble salt solution used for impregnation is one or more of nickel nitrate, nickel sulfate, magnesium nitrate, magnesium sulfate, aluminum nitrate, aluminum sulfate, zinc nitrate, and zinc sulfate.

21. The method of claim 20, wherein, In step (5), the metal oxide additive is nickel oxide, and the water-soluble salt solution used for impregnation is nickel nitrate and / or nickel sulfate.

22. A method for producing succinic anhydride, wherein, The method includes the following steps: gas-phase hydrogenation of maleic anhydride using a catalyst as described in any one of claims 1-7 or a catalyst prepared by the method as described in any one of claims 8-21 at atmospheric pressure and a reaction temperature of 250-290°C.

23. The method of claim 22, wherein, The gas-phase hydrogenation is carried out in a fixed-bed reactor.

24. The method of claim 22 or 23, wherein, The conditions for gas-phase hydrogenation are: reaction temperature 250-290℃, hydrogen flow rate 600-1000 mL / min, and maleic anhydride flow rate 0.01-0.1 mL / min.

25. The use of the catalyst according to any one of claims 1-7, or the catalyst prepared by the method according to any one of claims 8-21, for catalyzing the gas-phase hydrogenation of maleic anhydride at atmospheric pressure and a reaction temperature of 250-290°C to produce succinic anhydride.

26. The use of the catalyst according to any one of claims 1-7, or the catalyst prepared by the method according to any one of claims 8-21, for improving the succinic anhydride conversion and / or selectivity in the production of succinic anhydride by gas-phase hydrogenation of maleic anhydride at atmospheric pressure and a reaction temperature of 250-290°C.

27. The use as described in claim 26, wherein, The succinic anhydride has a selectivity of over 90%.

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