A catalyst for preparing gamma-butyrolactone by hydrogenating maleic anhydride supported by alumina ceramic, a preparation method and application thereof

Abstract

The application discloses a catalyst for preparing gamma-butyrolactone by hydrogenating maleic anhydride and supported by alumina ceramics, a preparation method and application, and belongs to the technical field of supported catalysts. x O y @Au-SiO2 coating layer; the alumina ceramic support has a size of 3-5 mm and is spherical, columnar or Raschig ring-shaped; the C-Cu-M x O y @Au-SiO2 coating layer has a thickness of 0.1 mm-1 mm. The catalyst preparation method comprises the following steps: treating the alumina ceramic, preparing a flowable sol, preparing a first catalyst precursor, preparing a mixed Au sol solution, preparing a second catalyst precursor, preparing a third catalyst precursor, temperature rising reduction, and finally obtaining the catalyst for preparing gamma-butyrolactone by hydrogenating maleic anhydride and supported by alumina ceramics. The catalyst solves the problem of catalyst coking and deactivation caused by limited internal mass transfer and heat transfer of traditional catalyst particles.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of supported catalysts, and particularly relates to a preparation method of a catalyzer for preparing gamma-butyrolactone by hydrogenation of maleic anhydride and taking alumina ceramic as support. BACKGROUND

[0002] Gamma-butyrolactone (GBL) is an excellent high-boiling organic low-toxicity and proton-type solvent, which can be used as a cleaning agent for high-precision electronics, circuit boards and lithium batteries instead of strong corrosive acid liquid. With the rapid development of global electric vehicles and electronic industries, the demand for GBL is rapidly increasing. GBL can also react with ammonia to generate 2-pyrrolidone, and 2-pyrrolidone can react with acetylene to generate N-vinyl pyrrolidone. The polymerization of N-vinyl pyrrolidone generates polyvinyl pyrrolidone, which is an important intermediate of pyrrolidone compounds and is widely used in cosmetics. GBL can also react with methylamine to generate N-methyl pyrrolidone, which is widely used in the petroleum and chemical industry and can also be used as an antifreeze agent for high-grade lubricating oil. In addition, GBL is also used as a main intermediate for synthesizing ciprofloxacin, sedative gamma-hydroxybutyric acid and interferon.

[0003] Direct hydrogenation of maleic anhydride to produce GBL has the advantages of short process flow, low raw material price and high quality of produced GBL. According to the different states of maleic anhydride in the reaction process, the hydrogenation can be divided into gas-phase hydrogenation and liquid-phase hydrogenation. Compared with liquid-phase hydrogenation, gas-phase hydrogenation has the advantages of low reaction pressure, easy continuous production and easy recovery and utilization of reaction heat due to high reaction temperature, which has important industrial application value. Whether maleic anhydride hydrogenation can be selectively and directionally generated GBL depends on the construction of a suitable hydrogenation catalyst. According to the reported catalyst types, the catalysts mainly include noble metal and non-noble metal catalysts: although the noble metal catalysts (such as Pt, Pd, Ru, Re, etc.) exhibit good hydrogenation performance, the actual application is limited due to the cost problem, and therefore, the development of non-noble metal catalysts mainly including Cu, Ni and Zn has become the main trend of catalyst development.

[0004] The main catalysts currently used are multi-component catalysts composed of CuO, ZnO and Al2O3 [such as CN1298759A, CN1358568A, US 5122485, CN1058400A, CN1111167A], with Ba, Pd, Pt, etc. added as auxiliary agents. Most of these catalysts are prepared by co-precipitation and are formed into a certain shape by tabletting to form a uniform catalyst. The catalysts prepared by this method have a high specific surface area, providing a large number of active centers for the reaction, but due to the small pore size and long pore length, the diffusion of maleic anhydride raw material and GBL product in the pores is severely limited in the gaseous state, the residence time is prolonged, resulting in a high content of by-products such as THF, butyric acid, butanol, propionic acid, propanol, etc. and low selectivity of GBL; and the heat released by the strong exothermic hydrogenation reaction is difficult to quickly remove from the pores, easily causing local overheating and carbon deposition, and leading to serious blockage of the pore structure, a decrease in the utilization rate of active centers in the pores, and rapid deactivation of the catalyst.

[0005] Therefore, solving the engineering problem of mass and heat transfer inside the catalyst particles is an important strategy to improve the performance of the catalyst. SUMMARY

[0006] The purpose of the present application is to solve the problem of catalyst deactivation caused by the engineering problem of mass and heat transfer inside the catalyst particles in the preparation of gamma-butyrolactone from maleic anhydride, and the present application provides a preparation method of a catalyst for the preparation of gamma-butyrolactone from maleic anhydride supported by alumina ceramic.

[0007] The present application is realized by the following technical solutions:

[0008] According to a first aspect of the present application, a catalyst for the preparation of gamma-butyrolactone from maleic anhydride supported by alumina ceramic is provided, which is supported by alumina ceramic and has a C-Cu-M x O y @Au-SiO2 coating composition; the size of the alumina ceramic support is 3-5 mm, and the shape is spherical, cylindrical or Raschig ring; the C-Cu-M x O y @Au-SiO2 coating has a thickness of 0.1 mm-1 mm; the C-Cu-M x O y @Au-SiO2 coating, the mesopore size is 2 nm-3.6 nm, and the specific surface area is 98-132 m 2 / g.

[0009] Further, the C-Cu-M x O y @Au-SiO2 coating, the mass fraction of Cu is 40.1-60.2%, and the mass fraction of M x Oy 1.1-9.1% by mass, 0.1-0.24% by mass of C, 0.13-0.43% by mass of Au, and the balance of SiO2; wherein the Au nanoparticles have a size of 12-32 nm, and the Au nanoparticles are dispersed on the surface of the alumina ceramic support 3+ / Au 0 =1-3:1.

[0010] According to a second aspect of the present application, there is provided a preparation method of the above-mentioned catalyst for hydrogenation of maleic anhydride to gamma-butyrolactone supported by an alumina ceramic, comprising the following steps:

[0011] Step one: the alumina ceramic is placed in nitric acid and heated to reflux to remove surface impurities, and after the treatment is completed, the alumina ceramic is washed with distilled water to clean the residual nitric acid, and dried in an oven for standby, to obtain the alumina ceramic.

[0012] Step two: a mixed solution with a fixed alcohol / water ratio is prepared, and under stirring, copper salt, metal additive salt and surfactant are sequentially added, and after complete dissolution, polyfunctional acetoxy silane and tetraethyl orthosilicate (TEOS) are added, and an aqueous acetic acid solution is added dropwise to adjust the pH of the solution to 2-3, to obtain a copper salt mixed solution; then the copper salt mixed solution is heated to reflux at 30-80 ℃ for 3-24 h, to obtain a flowable sol.

[0013] Step three: the alumina ceramic obtained in step one is placed in the flowable sol obtained in step two, soaked for 2-4 h, and then the alumina ceramic is separated and dried in an oven at 50-80 ℃ for 10-15 h to remove water, to obtain a first catalyst precursor.

[0014] Step four: the heated and boiled aqueous chloroauric acid solution and the aqueous sodium citrate solution are mixed uniformly under strong stirring, and continue to boil for 30 min-60 min, and then the aqueous chloroauric acid solution is added again, to obtain a mixed Au sol solution.

[0015] Step five: the mixed Au sol solution obtained in step four is sprayed and immersed on the first catalyst precursor obtained in step three, and left to stand for 1-5 h, and then dried in an oven at 60-80 ℃ for 5-10 h, and calcined in a muffle furnace at 350-600 ℃ for 5-10 h, to obtain a second catalyst precursor; wherein the spraying and immersion amount of the mixed Au sol solution is 20-30 L per 100 Kg of the alumina ceramic.

[0016] Step six: at room temperature, cellulose acetate is dissolved in N,NIn a mixed solvent of dimethylformamide and acetone, a cellulose acetate spraying solution with a mass fraction of 3% to 8% was prepared. The spraying solution was then sprayed onto the second catalyst precursor obtained in step five. After standing for 1 to 5 hours, excess liquid was filtered off, and the precursor was dried in an oven at 50 to 80 °C for 10 to 15 hours to obtain the third catalyst precursor. The amount of spraying solution used was 20 to 30 L per 100 kg of alumina ceramic.

[0017] Step 7: The third catalyst precursor obtained in Step 6 is loaded into an atmosphere furnace, and after passing through a H2 / N2 mixed gas, it is heated and reduced to finally obtain the catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported by alumina ceramic.

[0018] Furthermore, in step one, the alumina ceramic is spherical, columnar, or Raschig ring-shaped, with a size of 3-5 mm; the concentration of nitric acid is 20%-30%, and the amount of nitric acid used is calculated based on 300 L of nitric acid per 100 kg of alumina ceramic; the heating reflux temperature is 130-150 ℃, and the heating reflux time is 2-8 h; the number of times the distilled water is washed is 2-5 times; the oven drying temperature is 50-70 ℃, and the drying time is 4-8 h.

[0019] Furthermore, in step two, the volume ratio of ethanol to distilled water in the alcohol / water mixture is 10:1 to 30:1; the copper salt is one or both of copper nitrate trihydrate and copper nitrate hexahydrate, and the mass concentration of Cu in the fluid sol is 12 g / L to 24 g / L; the metal auxiliary salt is one or more of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and cerium nitrate hexahydrate, and the mass concentration of the metal auxiliary salt in the fluid sol is expressed as oxide M x O y The concentration of acetic acid in the fluid sol is 0.3 g / L to 3.6 g / L, expressed as SiO2. The surfactant is one or both of polyvinylpyrrolidone (PVP) and cetyl ammonium bromide (CTAB), with a concentration of 1 g / L to 6 g / L. The polyfunctional acetoxysilane is 3-acetoxypropyltrimethoxysilane or ethyltriacetoxysilane, with a concentration of 0.3 g / L to 0.6 g / L. The concentration of tetraethyl orthosilicate in the fluid sol, expressed as SiO2, is 10.36 g / L to 15.93 g / L. The concentration of acetic acid in the fluid sol is 20 g / L to 100 g / L.

[0020] Furthermore, in step three, the amount of flowable sol used is 300 L to 500 L, calculated based on 100 kg of alumina ceramic.

[0021] Further, in step four, the mass concentration of chloroauric acid in the aqueous chloroauric acid solution is 0.12 g / L to 0.18 g / L, the mass concentration of sodium citrate in the aqueous sodium citrate solution is 2.6 g / L to 18 g / L, and the aqueous sodium citrate solution and the aqueous chloroauric acid solution are mixed at a volume ratio of 2:100 to 6:100; the volume of the second addition of the aqueous chloroauric acid solution is 1 to 3 times the volume of the first addition of the aqueous chloroauric acid solution; and the Au nanoparticle size in the obtained mixed Au sol solution is 12 nm to 32 nm.

[0022] Further, in step six, the acetyl content in the cellulose acetate is 37% to 40%, N,N - the volume ratio of dimethylformamide to acetone is 0.2:1 to 3:1.

[0023] Further, in step seven, the H2 volume fraction in the H2 / N2 mixed gas is 0.5% to 10%, the reduction temperature is 160°C to 350°C, and the time is 2 h to 12 h.

[0024] According to a third aspect of the present application, the use of the above-mentioned butene-2-hydrogenation catalyst supported by alumina ceramic or the above-mentioned butene-2-hydrogenation catalyst prepared by the preparation method in the reaction of synthesizing butyrolactone from butene-2 and hydrogen is provided.

[0025] The catalyst obtained by the present application is applied to a heterogeneous system of butene-2 gas-phase hydrogenation to prepare butyrolactone, specifically, hydrogen and butene-2 vapor are mixed, and the gaseous material is reacted in a fixed bed reactor filled with the catalyst of the present application, wherein the reactor reaction temperature is 250-340 ℃, the reaction pressure is less than 0.5 MPa, the molar ratio of hydrogen to butene-2 is 40-180, the liquid weight space velocity of butene-2 is 0.03-0.24 hr -1 , the single-pass conversion rate of butene-2 is 100%, and the selectivity of butyrolactone can reach 95-99%.

[0026] The present application forms a macroscopic coating structure by using alumina ceramic with strong chemical stability and high mechanical stability as a carrier core on the basis of a traditional uniform copper-based hydrogenation catalyst, and coating the active component on the outer surface of the carrier, the internal alumina ceramic carrier plays a good supporting role, and after the active component is coated, it can be directly used in an industrial reactor after simple drying, calcination and reduction treatment. Avoid the traditional catalyst preparation process of first obtaining copper-based catalyst powder, then performing tabletting, extrusion and other forming steps, and shorten the preparation process. More importantly, the adverse effects of the added forming aids on the composition, structure and surface properties of the catalyst during the forming process are avoided, and the damage to the pore structure caused by mechanical extrusion is avoided, so that the optimal catalyst structure formed by the wet chemical process is maintained, and the catalyst exhibits better performance.

[0027] The hydrogenation reaction process of maleic anhydride has the characteristics of large reaction heat release and many by-products. How to quickly remove the reaction heat, prevent local overheating from causing catalyst coking and deactivation, and control the residence time of reactants in the catalyst to prevent excessive hydrogenation by-products caused by long residence time is crucial. The catalyst with macroscopic coating structure obtained by the present application has the active component on the outer surface of the alumina ceramic, and there is no long-range nanoscale pore structure. The catalytic reaction quickly occurs on the surface of the catalyst. It can effectively avoid the local coking and deactivation caused by the heat not being removed in time, and the production of excessive hydrogenation by-products such as THF, butyric acid, butanol, propionic acid, and propanol caused by long residence time of the reaction molecules in the long-range nanoscale pores of the traditional uniform catalyst.

[0028] The alumina ceramic surface uses copper-silicon oxide-functional acetoxy silane sol containing a metal additive as a coating impregnation liquid. On the one hand, the sol containing multi-functional acetoxy silane can form strong bonding with the hydroxyl groups on the surface of the alumina ceramic treated with nitric acid, so that the catalyst active component layer is firmly combined with the alumina ceramic, preventing the active component from falling off due to airflow erosion during the reaction. On the other hand, the network structure of the SiO2 sol greatly increases the number of exposed Cu active sites in the catalyst. The interaction between the active component Cu and the network structure of SiO2 can also inhibit the aggregation and loss of the catalytically active component. At the same time, the presence of the oxide additive can form a strong interaction with the copper species, further improving the dispersion of the Cu species and inhibiting its agglomeration and deactivation. During the reaction, the metal additive can also adsorb oxygen atoms in maleic anhydride, increasing the concentration of maleic anhydride on the active sites of the catalyst, achieving one-step hydrogenation of maleic anhydride to the target product, and improving the selectivity of the catalyst.

[0029] Spraying a gold coating on the catalyst, gold and copper can simultaneously act as active sites to catalyze the hydrogenation reaction. In addition, gold nanoparticles have a long-range electronic regulation effect, which can effectively regulate the electronic valence of copper species and inhibit the deactivation of copper species during the catalytic process. The use of surfactants can effectively disperse the copper species, allowing each component in the catalyst to grow to an appropriate grain size. During the subsequent calcination process, the surfactant can be carbonized together with cellulose acetate to create pores and modify the carbon points in the catalyst. Carbon point modification can adjust the hydrophilic and hydrophobic properties of the catalyst surface, making the catalyst surface appropriately hydrophobic and oleophilic, greatly improving the hydrogenation activity of the catalyst, and preventing the hydration damage of the catalyst by by-products such as water, thereby prolonging the service life of the catalyst. DETAILED DESCRIPTION

[0030] The present application provides a maleic anhydride hydrogenation catalyst for preparing γ-butyrolactone supported by alumina ceramic, which comprises C-Cu-M x O yAu-SiO2 coating layer composition; the size of the alumina ceramic support is 3-5 mm, and the shape is spherical, columnar or Raschig ring; C-Cu-M x O y @The thickness of the Au-SiO2 coating layer is 0.1 mm-1 mm; C-Cu-M x O y @In the Au-SiO2 coating layer, the mesopore size is 2 nm-3.6 nm, the specific surface area is 98-132 m 2 / g. C-Cu-M x O y @In the Au-SiO2 coating layer, the mass fraction of Cu is 40.1-60.2%, the mass fraction of M x O y The mass fraction of C is 0.1-0.24%, the mass fraction of Au is 0.13-0.43%, and the rest is SiO2; wherein, the size of Au nanoparticles is 12-32 nm, Au 3+ / Au 0 =1-3:1.

[0031] The application also provides a preparation method of the above-mentioned catalyst for preparing gamma-butyrolactone by hydrogenation of maleic anhydride with alumina ceramic as support, comprising the following steps:

[0032] Step one: place the alumina ceramic in nitric acid, heat and reflux to remove surface impurities, after treatment, wash with distilled water to clean the residual nitric acid, and dry in an oven for standby, to obtain the alumina ceramic.

[0033] In the above-mentioned step, the shape of the alumina ceramic is spherical, columnar or Raschig ring, and the size is 3-5 mm; the concentration of the nitric acid is 20%-30%, and the amount of the nitric acid is calculated as 300 L of nitric acid per 100 Kg of alumina ceramic; the heating reflux temperature is 130-150 DEG C, and the heating reflux time is 2-8 h; the number of distilled water washing is 2-5 times; the oven drying temperature is 50-70 DEG C, and the drying time is 4-8 h.

[0034] Step two: prepare a mixed solution with a fixed alcohol / water ratio, and use it as a solvent to add copper salt, metal additive salt and surfactant under stirring, after complete dissolution, add multifunctional acetoxy silane and tetraethyl orthosilicate, and drop acetic acid aqueous solution to adjust the pH of the solution to 2-3, to obtain a copper salt mixed solution; then heat and reflux the copper salt mixed solution at 30-80 DEG C for 3-24 h, to obtain a flowable sol.

[0035] In the above step, the volume ratio of ethanol to distilled water in the alcohol / water mixed solution is 10:1-30:1; the copper salt is one or both of copper nitrate trihydrate and copper nitrate hexahydrate, and the mass concentration of Cu in the flowable sol is 12 g / L-24 g / L; the metal additive salt is one or more of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and cerium nitrate hexahydrate, and the mass concentration of the metal additive salt in the flowable sol, in the form of oxide M x O y 0.3 g / L-3.6 g / L; the surfactant is one or both of polyvinylpyrrolidone and cetyl ammonium bromide, and the mass concentration of the surfactant in the flowable sol is 1 g / L-6 g / L; the multifunctional acetoxy silane is 3-acetoxypropyl trimethoxysilane or ethyl triacetoxy silane, and the mass concentration of the multifunctional acetoxy silane in the flowable sol is 0.3 g / L-0.6 g / L; the mass concentration of tetraethyl orthosilicate in the flowable sol, in the form of SiO2, is 10.36 g / L-15.93 g / L; and the mass concentration of acetic acid in the flowable sol is 20 g / L-100 g / L.

[0036] Step three: the alumina ceramic obtained in step one is placed in the flowable sol obtained in step two, soaked for 2-4 h, separated, and dried in an oven at 50-80 ℃ for 10-15 h to remove water, to obtain a first catalyst precursor.

[0037] In the above step, the amount of the flowable sol is 300 L-500 L per 100 Kg of the alumina ceramic.

[0038] Step four: the heated and boiled chloroauric acid aqueous solution and the sodium citrate aqueous solution are mixed uniformly under strong stirring, and boiled for another 30 min-60 min, and then the chloroauric acid aqueous solution is added again to obtain a mixed Au sol solution.

[0039] In the above step, the mass concentration of chloroauric acid in the chloroauric acid aqueous solution is 0.12 g / L-0.18 g / L, the mass concentration of sodium citrate in the sodium citrate aqueous solution is 2.6 g / L-18 g / L, and the sodium citrate aqueous solution and the chloroauric acid aqueous solution are mixed at a volume ratio of 2:100-6:100; the volume of the chloroauric acid aqueous solution added for the second time is 1-3 times the volume of the chloroauric acid aqueous solution added for the first time; and the size of the Au nanoparticles in the obtained mixed Au sol solution is 12 nm-32 nm.

[0040] Step five: the mixed Au sol solution obtained in step four is sprayed onto the first catalyst precursor obtained in step three, and is left to stand for 1-5 h, and then is dried in an oven at 60-80 ℃ for 5-10 h, and is calcined in a muffle furnace at 350-600 ℃ for 5-10 h, to obtain a second catalyst precursor; wherein the spraying amount of the mixed Au sol solution is 20-30 L per 100 Kg of the alumina ceramic.

[0041] Step six: at room temperature, cellulose acetate is dissolved in a mixed solvent of dimethylformamide and acetone to prepare a spraying solution with a cellulose acetate mass fraction of 3%-8%, and the spraying solution is sprayed onto the second catalyst precursor obtained in step five, and is left to stand for 1-5 h, and then is dried in an oven at 50-80 ℃ for 10-15 h after excess liquid is filtered off, to obtain a third catalyst precursor; wherein the spraying amount of the spraying solution is 20-30 L per 100 Kg of the alumina ceramic. N,N In the above steps, the acetyl content in the cellulose acetate is 37%-40%, and the volume ratio of dimethylformamide to acetone is 0.2:1-3:1.

[0042] N,N In the above steps, the acetyl content in the cellulose acetate is 37%-40%, and the volume ratio of dimethylformamide to acetone is 0.2:1-3:1.

[0043] Step seven: the third catalyst precursor obtained in step six is loaded into an atmosphere furnace, and is reduced by heating after H2 / N2 mixed gas is introduced, to finally obtain the alumina ceramic supported maleic anhydride hydrogenation γ-butyrolactone catalyst.

[0044] In the above steps, the H2 volume fraction in the H2 / N2 mixed gas is 0.5%-10%, the reduction temperature is 160 ℃-350 ℃, and the time is 2 h-12 h, which can be preferably 4 h-8 h.

[0045] The application further provides an application of the alumina ceramic supported maleic anhydride hydrogenation γ-butyrolactone catalyst or the alumina ceramic supported maleic anhydride hydrogenation γ-butyrolactone catalyst prepared by the above preparation method in a reaction of synthesizing γ-butyrolactone from maleic anhydride and hydrogen.

[0046] Further, in order for those skilled in the art to better understand the application, the technical solutions of the application are further clearly and completely described below in combination with specific examples. It should be noted that the features in the embodiments and examples in the present application can be combined with each other without conflict. It should be understood that the specific examples described herein are only used to explain the application, and are not used to limit the application. Example 1

[0047] ​As shown in Table 1, 100 Kg of alumina ceramic with a diameter of 3-5 mm in spherical, cylindrical or Rasching ring shape was weighed and placed in 300 L of 20%-30% nitric acid, heated to reflux at 130-150 °C for 2-8 h to remove impurities therein and modify the surface. After filtering off the nitric acid solution, washing with distilled water for 2-5 times until neutral, and air drying at 50-70 °C for 4-8 h, the alumina ceramic was obtained and ready for use;

[0048] Table 1 Treatment conditions of alumina ceramic

[0049] Example 2

[0050] 400 L of an alcohol-water solution uniformly mixed from ethanol and distilled water in a volume ratio of 10:1-30:1 was taken, and under strong stirring, the required mass of copper nitrate trihydrate and / or copper nitrate hexahydrate, one or several of zinc nitrate hexahydrate, cerium nitrate hexahydrate, aluminum nitrate nonahydrate, tetraethyl orthosilicate (TEOS), polyvinylpyrrolidone (PVP) and / or cetyltrimethylammonium bromide (CTAB) was added in sequence according to the conditions listed in Table 2, and after complete dissolution, an aqueous acetic acid solution with a mass concentration of acetic acid of 20 g / L-100 g / L was added to adjust the pH value of the system to 2-3, and then the alcohol-water solution uniformly mixed from ethanol and distilled water in a volume ratio of 10:1-30:1 was added to make up to 500 L, to obtain a copper salt mixed solution. The mass concentration of copper in the copper salt mixed solution was 12 g / L-24 g / L, the mass concentration of metal additives, calculated as MxOy, was controlled to be 0.3 g / L-3.6 g / L, the mass concentration of surfactant was controlled to be 1 g / L-6 g / L, and the mass concentration of multifunctional acetoxy silane in the flowable sol was 0.3 g / L-0.6 g / L; the mass concentration of TEOS, calculated as SiO2, was controlled to be 10.36 g / L-15.93 g / L. Subsequently, the copper salt mixed solution was heated to reflux at 30-80 °C for 3-24 h to obtain a flowable sol;

[0051] Table 2 Preparation of flowable sol

[0052] Example 3

[0053] According to the conditions in Table 3, 100 Kg of alumina ceramic treated in Example 1 was placed in 300 L-500 L of flowable sol prepared in Example 2, soaked for 2-4 h, and after filtering off the excess liquid, the alumina ceramic was air dried at 50-80 °C for 10-15 h to obtain a first catalyst precursor;

[0054] Table 3 Preparation conditions of first catalyst precursor

[0055] Example 4

[0056] Preparation of mixed Au sol solutions. As shown in Table 4, 12-18 g of chloroauric acid was weighed and dissolved in deionized water, and the volume was adjusted to 100 L to obtain a chloroauric acid aqueous solution with a mass concentration of 0.12-0.18 g / L, which was then heated to boiling. 26-180 g of sodium citrate was weighed and dissolved in deionized water, and the volume was adjusted to 10 L to obtain a sodium citrate aqueous solution with a mass concentration of 2.6-18 g / L. 2-6 L of the sodium citrate aqueous solution was heated to boiling and added to 100 L of the boiling chloroauric acid aqueous solution under strong stirring. The solution was boiled for another 30-60 minutes. Then, a second batch of chloroauric acid aqueous solution was added, with the volume of the second batch being 1-3 times that of the first batch. This yielded a mixed Au sol solution with Au nanoparticle sizes of 12-32 nm, resulting in mixed Au sol solutions numbered Au1-Au6.

[0057] Table 4. Preparation conditions of mixed Au sol solution

[0058] Example 5

[0059] According to the conditions in Table 5, 20-30 L of the mixed Au sol solution numbered Au1-Au6 prepared in Example 4 was measured and sprayed onto the first catalyst precursor prepared in Example 3. After standing for 1-5 h, it was dried in a forced air at 60-80 ℃ for 5-10 h and calcined at 350-600 ℃ for 5-10 h to obtain the second catalyst precursor.

[0060] Table 5 Preparation conditions of the second catalyst precursor

[0061] Example 6

[0062] At room temperature, cellulose acetate with an acetyl content of 37%–40% is dissolved in… N,N A 3%–8% (w / w) cellulose acetate impregnation solution was prepared in a mixed solvent of dimethylformamide (DMF) and acetone. 20–30 L of the impregnation solution was sprayed onto the second catalyst precursor, allowed to stand for 1–5 h, excess liquid was filtered off, and the precursor was dried at 50–80 °C for 10–15 h to obtain the third catalyst precursor.

[0063] Table 6 Preparation conditions of the third catalyst precursor

[0064] Example 7

[0065] The catalyst was evaluated in a fixed bed reactor. The catalyst was loaded into a stainless steel fixed bed reactor with an inner diameter of 30 mm (catalyst bed height 1000 mm), and reduced in a H2 / N2mixed gas with a H2volume fraction of 0.5% to 10% by electric heating control, at a temperature increasing rate of 0.5°C / min to 5°C / min to 160°C to 350°C, for 2 h to 12 h, preferably 4 h to 8 h. The reaction temperature was adjusted to 250°C, the reaction pressure was less than 0.5 MPa, the molar ratio of hydrogen to maleic anhydride was 40 to 180, and the liquid weight hourly space velocity of maleic anhydride was 0.03 to 0.24 hr -1 The single-pass conversion rate of maleic anhydride was 100%, and the selectivity of γ-butyrolactone could reach 95% to 99%. During the reaction process, when the activity of the catalyst decreased, the reaction temperature was appropriately increased to continue the reaction, and finally the temperature was increased to 340°C, and the reaction was completed in a reaction cycle. After regeneration, the catalyst was re-fed into the next reaction cycle;

[0066] Table 7 Application conditions and evaluation results of the catalyst

[0067]

[0068] In the above Table 7, a The temperature interval at different positions in the bed during the constant temperature reduction process; b Due to the need to appropriately increase the reaction temperature to achieve the best reaction effect as the activity decreases during the reaction process, the recorded reaction temperature is the temperature interval of the highest temperature in the bed with the change of the reaction time. Example 8

[0069] The obtained catalysts 1 to 7 were tested for physical and chemical properties under the reduction conditions listed in Example 7. The catalysts were observed to be spherical, cylindrical or Raschig ring-shaped with a diameter of 3 to 5 mm, and the coating layer had a thickness of 0.1 mm to 1 mm. The coating layer was scraped off and tested for its composition, which was C, Cu, M x O y and Au. The mass fraction of Cu in the coating layer was 40.1% to 60.2%, the mass fraction of M x O y was 1.1% to 9.1%, the mass fraction of C was 0.1% to 0.24%, the mass fraction of Au was 0.13% to 0.43%, and the rest was SiO2. The size of the Au nanoparticles was 11 to 33 nm, and the Au 3+ / Au 0 ratio was 1 to 3:1. The size of the mesoporous channels in the coating layer was 2 nm to 3.6 nm, and the specific surface area was 98 to 132 m 2 / g;

[0070] Table 8 Coating layer property parameters of catalysts 1-7

[0071]

[0072] The above embodiments only express the most optimal implementation of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application.

Claims

1. A catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported on an alumina ceramic, characterized in that: C-Cu-M on the surface of alumina ceramic support x O y @Au-SiO2 coating layer composition; the size of the alumina ceramic support is 3-5 mm, and the shape is spherical, columnar or Laxi ring; C-Cu-M x O y @The thickness of Au-SiO2 coating layer is 0.1 mm-1 mm; C-Cu-M x O y @In Au-SiO2 coating layer, the mesoporous channel size is 2 nm-3.6 nm, the specific surface area is 98-132 m 2 / g, M is one or more of zinc, aluminum and cerium.

2. The catalyst for preparing γ-butyrolactone by hydrogenation of maleic anhydride supported by aluminum oxide ceramic according to claim 1, characterized in that: C-Cu-M x O y @In the Au-SiO2coating layer, the mass fraction of Cu is 40.1-60.2%, M x O y The mass fraction of C is 1.1-9.1%, the mass fraction of Au is 0.1-0.24%, and the mass fraction of Au is 0.13-0.43%, and the rest is SiO2; wherein, the size of Au nanoparticles is 12-32 nm, Au 3+ / Au 0 =1-3:

1.

3. A method for preparing a catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported on an alumina ceramic according to claim 1, characterized in that, Comprising the following steps: Step one: the alumina ceramic is placed in nitric acid, heated to reflux to remove surface impurities, after treatment, using distilled water to wash, in order to clean the residual nitric acid, and dried in the oven for standby, get alumina ceramic; Step two: preparation of fixed alcohol / water ratio of mixed solution, and use it as solvent, under stirring conditions, add copper salt, metal additive salt and surfactant in turn, after completely dissolved, add multi-functional acetoxy silane, tetraethyl orthosilicate, and drop acetic acid aqueous solution to adjust the pH of the solution to 2~3, get copper salt mixed solution; then the copper salt mixed solution is heated to reflux at 30~80 ℃ for 3~24 h, get the flowable sol; Step three: the alumina ceramic obtained in step one is placed in the flowable sol obtained in step two, soaked for 2~4 h, then separate the alumina ceramic, and dry in the oven at 50~80 ℃ for 10~15 h to remove water, get the first catalyst precursor; Step four: mix the heated boiling chloroauric acid aqueous solution with sodium citrate aqueous solution uniformly under strong stirring conditions, continue to boil for 30 min~60 min, then add chloroauric acid aqueous solution again, get mixed Au sol solution; Step five: the mixed Au sol solution obtained in step four is sprayed onto the first catalyst precursor obtained in step three, stand for 1~5 h, then dry in the oven at 60~80 ℃ for 5~10 h, calcine in the muffle furnace at 350~600 ℃ for 5~10 h, get the second catalyst precursor; wherein the spraying amount of the mixed Au sol solution is 20~30 L per 100 kg of alumina ceramic; Step six: cellulose acetate is dissolved in N,N - a mixture solvent of dimethylformamide and acetone, a spraying solution with a cellulose acetate mass fraction of 3% to 8% is prepared, the spraying solution is sprayed into the second catalyst precursor obtained in step five, and is placed for 1 h to 5 h, after excessive liquid is filtered off, drying is performed in an oven at 50 to 80 ℃ for 10 to 15 h, to obtain a third catalyst precursor; wherein the spraying solution is sprayed in an amount of 20 to 30 L, based on 100 kg of the alumina ceramic. Step seven: the third catalyst precursor obtained in step six is loaded into the atmosphere furnace, reduce after passing in H2 / N2mixed gas, finally get the said alumina ceramic supported catalyst for hydrogenation of maleic anhydride to γ-butyrolactone.

4. A process for the preparation of a catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported on an alumina ceramic according to claim 3, characterized in that: In step one, the shape of the alumina ceramic is spherical, columnar or raschig ring, and the size is 3~5 mm; the concentration of the nitric acid is 20%~30 %, and the amount of the nitric acid is calculated as 300 L per 100 kg of alumina ceramic; the heating reflux temperature is 130~150 ℃, and the heating reflux time is 2~8 h; the number of distilled water washing is 2~5 times; the oven drying temperature is 50~70 ℃, and the drying time is 4~8 h.

5. A process for the preparation of a catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported on an alumina ceramic according to claim 3, characterized in that: In the step two, the volume ratio of ethanol to distilled water in the alcohol / water mixed solution is 10:1-30:1; the copper salt is one or both of copper nitrate trihydrate and copper nitrate hexahydrate, the mass concentration of Cu in the flowable sol is 12 g / L-24 g / L; the metal additive salt is one or more of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and cerium nitrate hexahydrate, the mass concentration of the metal additive salt in the flowable sol, in the form of oxide M x O y is 0.3 g / L-3.6 g / L; the surfactant is one or both of polyvinylpyrrolidone and cetyl ammonium bromide, the mass concentration of the surfactant in the flowable sol is 1 g / L-6 g / L; the multifunctional acetoxy silane is 3-acetoxypropyl trimethoxysilane or ethyl triacetoxy silane, the mass concentration of the multifunctional acetoxy silane in the flowable sol is 0.3 g / L-0.6 g / L; the mass concentration of tetraethyl orthosilicate in the flowable sol, in the form of SiO2, is 10.36 g / L-15.93 g / L; and the mass concentration of acetic acid in the flowable sol is 20 g / L-100 g / L.

6. A process for the preparation of a catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported on an alumina ceramic according to claim 3, characterized in that: In step three, the amount of the flowable sol is 300 L~500 L per 100 kg of alumina ceramic.

7. A process for the preparation of a catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported on an alumina ceramic according to claim 3, characterized in that: In step four, the mass concentration of chloroauric acid in the chloroauric acid aqueous solution is 0.12 g / L~0.18 g / L, the mass concentration of sodium citrate in the sodium citrate aqueous solution is 2.6 g / L~18 g / L, and the sodium citrate aqueous solution is mixed with the chloroauric acid aqueous solution at a volume ratio of 2:100~6:100; the volume of the second added chloroauric acid aqueous solution is 1~3 times of the volume of the first added chloroauric acid aqueous solution; the size of Au nanoparticles in the obtained mixed Au sol solution is 12 nm~32 nm.

8. A process for the preparation of a catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported on an alumina ceramic according to claim 3, characterized in that: In step six, the acetyl content of the cellulose acetate is 37% to 40%, N,N - the volume ratio of dimethylformamide to acetone is 0.2:1 to 3:

1.

9. A process for the preparation of a catalyst for the hydrogenation of maleic anhydride to γ-butyrolactone supported on an alumina ceramic according to claim 3, characterized in that: In step seven, the H2 volume fraction in the H2 / N2 mixed gas is 0.5%-10%, the reduction temperature is 160-350°C, and the time is 2-12 hours.

10. The use of the catalyst for preparing γ-butyrolactone by hydrogenation of maleic anhydride supported on alumina ceramic according to claim 1 or 2 or prepared by the method according to any one of claims 3-9 in the reaction of synthesizing γ-butyrolactone from maleic anhydride and hydrogen.

Images