Preparation method and application of copper-based composite catalyst for producing 1, 4-butanediol

Abstract

The invention discloses a preparation method of a copper-based composite catalyst for producing 1, 4-butanediol, which comprises the following steps: (1) adding aluminum oxide into deionized water, dispersing uniformly, and pulping to obtain a solution A; adding a copper salt, a zinc salt and a barium salt into water to obtain a mixed solution, then dropwise adding the mixed solution into the solution A for adsorption reaction, and stirring to obtain an active group suspension; (2) dropwise adding ammonia water into the active suspension obtained in the step (1) for preliminary precipitation reaction, stirring for 30 minutes, distilling ammonia at high temperature, controlling the pH to be 5-9, and aging to obtain a precipitation precursor; and (3) carrying out suction filtration, washing and drying on the precipitate precursor obtained in the step (2), roasting in a nitrogen atmosphere to obtain a copper-based catalyst precursor, and roasting at 350-800 DEG C for 1-12 hours to obtain the copper-based composite catalyst. Meanwhile, the prepared catalyst is used for synthesizing 1, 4-butanediol through dimethyl succinate hydrogenation. The conversion rate of the catalyst in ester hydrogenation reaction can reach 100%, and the BDO selectivity is greater than or equal to 95%.

Description

Technical Field

[0001] The invention belongs to the field of industrial catalysts, and particularly relates to a preparation method and application of a copper-based composite catalyst for producing 1,4-butanediol. Background Art

[0002] 1,4-Butanediol (BDO) is an important basic organic raw material for fine chemicals, which is widely used in the fields of medicine, chemical industry, textile, papermaking, automobile and daily chemicals. 1,4-Butanediol can be used to produce tetrahydrofuran (THF), polybutylene terephthalate (PBT), γ-butyrolactone (GBL), polyurethane resin, coating and plasticizer, etc. It can also be used as solvent and brightener in electroplating industry.

[0003] At present, the production processes of BDO include the acetylene aldehyde method (Reppr method), the propylene oxide method, the two-step method using n-butane as raw material, the maleic anhydride (MA) esterification hydrogenation method, the maleic anhydride direct hydrogenation method, the n-butane direct synthesis method, etc. Among them, the route of synthesizing BDO by hydrogenation of maleic anhydride is clean and environmentally friendly and has attracted widespread attention. Maleic anhydride is a stable five-membered ring structure with C—O—C, C=O, and C=C functional groups, of which two C=O are conjugated with C=C respectively. If the C=C and C=O of maleic anhydride are hydrogenated at the same time, the hydrogenation capacity of the catalyst is required to be high. Therefore, it is particularly critical to design and prepare a highly active and highly selective maleic anhydride hydrogenation catalyst for synthesizing BDO.

[0004] Sinopec Fushun Petrochemical Research Institute has developed a copper-chromium catalyst prepared by combustion method for the gas phase hydrogenation process of dimethyl maleate. The catalyst is prepared by co-precipitating copper and chromium salt solution with citric acid and alkali solution at a certain pH and temperature, and then drying and grinding the obtained precipitate, adding ethanol and igniting it to finally obtain a copper-chromium catalyst. Under the gas phase reaction conditions of 190°C and 6 MPa, the hydrogenation conversion rate of dimethyl maleate by copper-chromium catalyst is 100%, and the yield of BDO is increased to 87%. Although the yield of BDO has increased, the use and treatment of chromium-containing catalysts still pose great risks to the environment and human health. David Company disclosed a production process of generating diethyl ester by esterification of maleic anhydride, and then converting diethyl ester into γ-butyrolactone, 1,4-butanediol and tetrahydrofuran through two hydrogenation reactors, and the hydrogenation process is achieved using a catalyst composed of Cu-Cr-O. Although the Cu-Cr-O catalyst has good hydrogenation activity and selectivity for 1,4-butanediol, the production and recovery of this type of chromium-containing catalyst is bound to cause environmental pollution. CN1116616A reports a method for producing 1,4-butanediol, that is, dialkyl maleate is used as a raw material, and 1,4-butanediol is produced by gas phase hydrogenation reaction under the action of a catalyst composed of Cu-Zn-Cr-Zr. Under the conditions of liquid feed space velocity of 0.4h-1 and reaction temperature of 220°C and reaction pressure of 6MPa, the conversion rate is 99% and the selectivity of 1,4-butanediol is 79%. Although the above catalysts all have good hydrogenation activity and selectivity for 1,4-butanediol, the production and recovery of this type of chromium-containing catalyst is bound to cause environmental pollution.

[0005] CN116514636 A reported a method for preparing 1,4-butanediol by a two-step hydrogenation process using dimethyl maleate as a raw material, Cuy-Alz-Mv as a catalyst, and 1,4-dioxane as a solvent. The conversion rate of dimethyl maleate after two-step hydrogenation reached 100%, and the BDO yield reached more than 91%. Although the yield of BDO has increased, the preparation method has many steps and is not conducive to large-scale industrial application. CN116803503 A reported a Co-XM / SiO2 catalyst for preparing 1,4-butanediol by hydrogenation of succinic acid, wherein SiO2 is a carrier, X is selected from one or two of Cu, Ni, Fe, Zn, Mn, Mo, V or Cr metal elements, and M is selected from alkali metal oxides and alkaline earth metal oxides. The catalyst was added to a reactor with a volume of 25 ml and reacted for 8 hours at 180°C and 5MPa hydrogen pressure. After the reaction, the reaction liquid is separated from the catalyst by centrifugation and filtration. 1,4-butanediol is obtained at a lower reaction temperature, moderate hydrogen pressure, and a shorter reaction time, and the yield can reach more than 95%. However, the catalyst hydrogenation reaction cannot continuously produce 1,4-butanediol and the process is cumbersome, which is not suitable for large-scale chemical production. This catalyst is hydrogenated in a fixed bed reactor, can continuously produce 1,4-butanediol, and the catalyst preparation method is simple, which is friendly to the environment and human health. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a catalyst for producing 1,4-butanediol by hydrogenation of esters, in particular, a method for preparing a copper-based composite catalyst for hydrogenation of dimethyl succinate to produce 1,4-butanediol; the element composition of the catalyst is copper, zinc, barium, aluminum and oxygen, and does not contain chromium elements that are not environmentally friendly. The catalyst prepared by the method of the present invention has high reaction activity and product selectivity for hydrogenation to produce 1,4-butanediol, and has less by-product components.

[0007] A method for preparing a copper-based composite catalyst for producing 1,4-butanediol comprises the following steps: (1) Add alumina to deionized water and disperse it evenly, then slurry it to obtain solution A; add copper salt, zinc salt and barium salt to water to obtain a mixed solution, then drop the mixed solution into solution A to perform adsorption reaction, stir and obtain an active group suspension; (2) adding ammonia water dropwise to the active component suspension obtained in step (1) for a preliminary precipitation reaction, stirring for 30 min, evaporating ammonia at high temperature, controlling the pH at 5-9, and aging to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) is filtered, washed, dried, and calcined in a nitrogen atmosphere to obtain a copper-based catalyst precursor, and then calcined at 350-800° C. for 1-12 h to obtain a copper-based composite catalyst.

[0008] Preferably, the molar ratio of aluminum oxide, copper salt, zinc salt and barium salt in step (1) is: (0.05-1): 1: (0.48-1): (0.03-0.1).

[0009] Preferably, in step (1), the copper salt is copper nitrate trihydrate, copper sulfate pentahydrate or copper chloride monohydrate; and the zinc salt is zinc nitrate hexahydrate, zinc sulfate heptahydrate or zinc chloride dihydrate.

[0010] Preferably, the dropping in step (1) is carried out while solution A is stirred, the dropping speed is 5 mL / min, the dropping temperature is 25° C., and the stirring speed of solution A is 100-800 r / min; the stirring time in step (1) is 20 min.

[0011] Preferably, the ammonia content in the ammonia water in step (2) is 1-25wt%.

[0012] Preferably, the dripping in step (2) is completed under stirring conditions, and the dripping speed is 3 min / L-70 min / L.

[0013] Preferably, the stirring rate is 100-800 r / min.

[0014] Preferably, the aging temperature in step (2) is 25-125° C. and the aging time is 2-12 h.

[0015] Preferably, the calcination temperature in nitrogen atmosphere in step (3) is 200-450° C. and the calcination time is 2-6 h.

[0016] The catalyst is used in the preparation of 1,4-butanediol and is used for hydrogenating dimethyl succinate to synthesize 1,4-butanediol.

[0017] Beneficial effects of the present invention: The present invention provides a copper-based composite catalyst for producing BDO and a preparation method thereof, that is, a copper-zinc-aluminum catalyst is obtained by a simple coprecipitation method. The method is simple to operate, low in cost, and can achieve large-scale industrial production and application. At the same time, the catalyst of the present invention can achieve a conversion rate of 100% in an ester hydrogenation reaction, and a BDO selectivity of ≥95%. DETAILED DESCRIPTION

[0018] Example 1 A method for preparing a copper-based composite catalyst for producing 1,4-butanediol comprises the following steps: (1) Add 2.5g of A12O3 to 250mL of deionized water at 25°C and disperse evenly, then slurry to obtain solution A; dissolve 120.8g of copper nitrate trihydrate, 71.76g of zinc nitrate hexahydrate, and 3.5g of barium nitrate in 500mL of deionized water at 25°C to obtain a mixed solution, and then drop the mixed solution into solution A at a flow rate of 5mL / min for adsorption reaction. The dropping temperature is 25°C and the stirring rate is 500r / min. After the adsorption is completed, stir for 20min to obtain an active group suspension; (2) adding ammonia water with an ammonia content of 1 wt% to the active group suspension at a flow rate of 3 min / L, and stirring at a speed of 500 r / min to carry out a preliminary precipitation reaction. After the addition is completed, stirring is carried out for 30 min, and then ammonia is evaporated at high temperature to uniformly precipitate. The pH value is adjusted to 5, and the mixture is aged at 25 ° C for 3 h to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) was filtered, washed, vacuum dried, and calcined at 400° C. in a nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, which was then calcined at 500° C. for 6 h to obtain a copper-based composite catalyst.

[0019] Example 2 The aging in step (2) is performed at 50° C. for 3 h, and the rest is the same as in Example 1.

[0020] Example 3 The aging in step (2) is performed at 70° C. for 3 h, and the rest is the same as in Example 1.

[0021] Example 4 The aging in step (2) is performed at 90° C. for 3 h, and the rest is the same as in Example 1.

[0022] Example 5 (the molar ratio of aluminum oxide, copper salt, zinc salt and barium salt is 0.5:1:1:0.1) A method for preparing a copper-based composite catalyst for producing BDO comprises the following steps: (1) Add 25.49 g of A12O3 to 250 mL of deionized water at 25°C and disperse evenly, then slurry to obtain solution A; dissolve 120.8 g of copper nitrate trihydrate, 143.52 g of zinc nitrate hexahydrate, and 13 g of barium nitrate in 500 mL of deionized water at 25°C to obtain a mixed solution, and then drop the mixed solution into solution A at a flow rate of 5 mL / min for adsorption reaction. The dropping temperature is 25°C and the stirring rate is 500 r / min. After the adsorption is completed, stir for 20 min to obtain an active group suspension; (2) adding ammonia water with an ammonia content of 15 wt% to the active group suspension at a flow rate of 3 min / L, and stirring at a speed of 500 r / min to carry out a preliminary precipitation reaction. After the addition is completed, stirring is carried out for 30 min, and then ammonia is evaporated at high temperature to uniformly precipitate. The pH value is adjusted to 5, and the mixture is aged at 90 ° C for 3 h to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) was filtered, washed, vacuum dried, and calcined at 400° C. in a nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, which was then calcined at 500° C. for 6 h to obtain a copper-based composite catalyst.

[0023] Example 6 (the molar ratio of aluminum oxide, copper salt, zinc salt and barium salt is 1:1:0.0.48:0.05) A method for preparing a copper-based composite catalyst for producing BDO comprises the following steps: (1) Add 50.98g of A12O3 to 250mL of deionized water at 25°C and disperse evenly, then slurry to obtain solution A; dissolve 120.8g of copper nitrate trihydrate, 71.76g of zinc nitrate hexahydrate, and 6.5g of barium nitrate in 500mL of deionized water at 25°C to obtain a mixed solution, and then drop the mixed solution into solution A at a flow rate of 5mL / min for adsorption reaction. The dropping temperature is 25°C and the stirring rate is 500r / min. After the adsorption is completed, stir for 20min to obtain an active group suspension; (2) adding ammonia water with an ammonia content of 20 wt% to the active group suspension at a flow rate of 3 min / L, and stirring at a speed of 500 r / min to carry out a preliminary precipitation reaction. After the addition is completed, stirring is carried out for 30 min, and then ammonia is evaporated at high temperature to uniformly precipitate. The pH value is adjusted to 5, and the mixture is aged at 90 ° C for 3 h to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) was filtered, washed, vacuum dried, and calcined at 400° C. in a nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, which was then calcined at 500° C. for 6 h to obtain a copper-based composite catalyst.

[0024] Example 7 (the molar ratio of aluminum oxide, copper salt, zinc salt and barium salt is 0.3:1:0.7:0.03) A method for preparing a copper-based composite catalyst for producing BDO comprises the following steps: (1) Add 15.29g of A12O3 to 250mL of deionized water at 25°C and disperse evenly, then slurry to obtain solution A; dissolve 120.8g of copper nitrate trihydrate, 104g of zinc nitrate hexahydrate, and 3.5g of barium nitrate in 500mL of deionized water at 25°C to obtain a mixed solution, and then drop the mixed solution into solution A at a flow rate of 5mL / min for adsorption reaction. The dropping temperature is 25°C and the stirring rate is 500r / min. After the adsorption is completed, stir for 20min to obtain an active group suspension; (2) adding ammonia water with an ammonia content of 25 wt% to the active group suspension at a flow rate of 3 min / L, and stirring at a speed of 500 r / min to carry out a preliminary precipitation reaction. After the addition is completed, stirring is carried out for 30 min, and then ammonia is evaporated at high temperature to uniformly precipitate. The pH value is adjusted to 5, and the mixture is aged at 90 ° C for 3 h to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) was filtered, washed, vacuum dried, and calcined at 400° C. in a nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, which was then calcined at 500° C. for 6 h to obtain a copper-based composite catalyst.

[0025] Example 8 Different calcination temperatures, specifically: low temperature calcination at 300° C. in a nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, and then calcination at 450° C. in a muffle furnace for 6 h. Others are the same as in Example 7.

[0026] Example 9 Different calcination temperatures, specifically: low temperature calcination at 350° C. in a nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, and then calcination at 500° C. in a muffle furnace for 6 h. Others are the same as in Example 7.

[0027] Example 10 Different calcination temperatures, specifically: low temperature calcination at 400° C. in nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, followed by calcination at 550° C. in a muffle furnace for 6 h. Others are the same as in Example 7.

[0028] Embodiment 11 Different pH values, the pH value was adjusted to 6, and the rest was the same as Example 7.

[0029] Example 12 Different pH values, the pH value was adjusted to 7, and the rest was the same as Example 7.

[0030] Embodiment 13 Different pH values, the pH value was adjusted to 9, and the rest was the same as Example 7.

[0031] Embodiment 14 A method for preparing a copper-based composite catalyst for producing 1,4-butanediol comprises the following steps: (1) Add 15.29 g of A12O3 to 250 mL of deionized water at 25°C and disperse evenly, then slurry to obtain solution A; dissolve 125 g of copper sulfate pentahydrate, 104 g of zinc nitrate hexahydrate, and 3.5 g of barium nitrate in 500 mL of deionized water at 25°C to obtain a mixed solution, and then drop the mixed solution into solution A at a flow rate of 5 mL / min for adsorption reaction. The dropping temperature is 25°C and the stirring rate is 800 r / min. After the adsorption is completed, stir for 20 min to obtain an active group suspension; (2) adding ammonia water with an ammonia content of 25 wt% to the active group suspension at a flow rate of 70 min / L, and stirring at a speed of 800 r / min to carry out a preliminary precipitation reaction. After the addition is completed, stirring is carried out for 30 min, and then ammonia is evaporated at high temperature to uniformly precipitate. The pH value is adjusted to 5, and the mixture is aged at 25 ° C for 12 h to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) was filtered, washed, vacuum dried, and calcined at 200° C. in a nitrogen atmosphere for 6 h to obtain a copper-based catalyst precursor, which was then calcined at 350° C. for 12 h to obtain a copper-based composite catalyst.

[0032] Embodiment 15 (1) Add 15.29 g of A12O3 to 250 mL of deionized water at 25°C and disperse evenly, then slurry to obtain solution A; dissolve 85.25 g of cupric chloride dihydrate, 100.6 g of zinc sulfate heptahydrate, and 3.5 g of barium nitrate in 500 mL of deionized water at 25°C to obtain a mixed solution, and then drop the mixed solution into solution A at a flow rate of 5 mL / min for adsorption reaction. The dropping temperature is 25°C and the stirring rate is 100 r / min. After the adsorption is completed, stir for 20 min to obtain an active group suspension; (2) adding ammonia water with an ammonia content of 1 wt% to the active group suspension at a flow rate of 3 min / L, and stirring at a speed of 100 r / min to carry out a preliminary precipitation reaction. After the addition is completed, stirring is carried out for 30 min, and then ammonia is evaporated at high temperature to uniformly precipitate. The pH value is adjusted to 5, and the mixture is aged at 125 ° C for 2 h to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) was filtered, washed, vacuum dried, and calcined at 450° C. in a nitrogen atmosphere for 2 h to obtain a copper-based catalyst precursor, which was then calcined at 800° C. for 1 h to obtain a copper-based composite catalyst.

[0033] Example 16 (1) Add 15.29 g of A12O3 to 250 mL of deionized water at 25°C and disperse evenly, then slurry to obtain solution A; dissolve 125 g of copper sulfate pentahydrate, 60.3 g of zinc chloride dihydrate, and 3.5 g of barium nitrate in 500 mL of deionized water at 25°C to obtain a mixed solution, and then drop the mixed solution into solution A at a flow rate of 5 mL / min for adsorption reaction. The dropping temperature is 25°C and the stirring rate is 500 r / min. After the adsorption is completed, stir for 20 min to obtain an active group suspension; (2) adding ammonia water with an ammonia content of 1 wt% to the active group suspension at a flow rate of 50 min / L, and stirring at a speed of 500 r / min to carry out a preliminary precipitation reaction. After the addition is completed, stirring is carried out for 30 min, and then ammonia is evaporated at high temperature to uniformly precipitate. The pH value is adjusted to 5, and the mixture is aged at 25 ° C for 3 h to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) was filtered, washed, vacuum dried, and calcined at 400° C. in a nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, which was then calcined at 500° C. for 6 h to obtain a copper-based composite catalyst.

[0034] Embodiment 17 (1) Add 15.29 g of A12O3 to 250 mL of deionized water at 25°C and disperse evenly, then slurry to obtain solution A; dissolve 120.8 g of copper nitrate trihydrate, 100.6 g of zinc sulfate heptahydrate, and 3.5 g of barium nitrate in 500 mL of deionized water at 25°C to obtain a mixed solution, and then drop the mixed solution into solution A at a flow rate of 5 mL / min for adsorption reaction. The dropping temperature is 25°C and the stirring rate is 500 r / min. After the adsorption is completed, stir for 20 min to obtain an active group suspension; (2) adding ammonia water to the active group suspension at a flow rate of 3 min / L to carry out a preliminary precipitation reaction, stirring for 30 min after the addition, and then evaporating ammonia at high temperature to uniformly precipitate, adjusting the pH value to 5, and aging at 25 ° C for 3 h to obtain a precipitate precursor; (3) The precipitated precursor obtained in step (2) was filtered, washed, vacuum dried, and calcined at 400° C. in a nitrogen atmosphere for 3 h to obtain a copper-based catalyst precursor, which was then calcined at 500° C. for 6 h to obtain a copper-based composite catalyst.

[0035] Comparative Example 1 No barium salt was added, and the rest was the same as in Example 6.

[0036] The catalysts obtained in Examples 6, 7, 8, 9, 10 and Comparative Example 1 were tableted to obtain samples with a particle size of 10-40 mesh. The performance of the catalyst was evaluated by an ester hydrogenation experiment. 9 g of the catalyst was placed in a quartz reaction tube with an inner diameter of 12 mm, and a hydrogenation experiment was performed on a fixed bed reactor. At a temperature of 220°C, hydrogen was introduced for 10 hours. Then, dimethyl succinate was used as the hydrogenation raw material, at 175°C, 6.5 MPa, a hydrogen-ester ratio of 70, and a liquid feed space velocity of 0.3 h -1 The performance of the catalyst was evaluated under the experimental conditions. The conversion rate of the ester hydrogenation reaction of the catalysts obtained in Examples 6, 7, 8, 9, and 10 can reach 100%, and the BDO selectivity is ≥95%.

[0037] Table 1 Catalyst performance evaluation results for hydrogenation of dimethyl succinate to produce BDO Note: THF—tetrahydrofuran; GBL—γ-butyrolactone; BDO—1,4-butanediol.

Claims

1. A method for preparing a copper-based composite catalyst for producing 1,4-butanediol, characterized in that: The following steps are involved: (1) Add alumina to deionized water and disperse it evenly, then slurry the solution to obtain solution A; Copper salt, zinc salt and barium salt are added into water to obtain a mixed solution, and then the mixed solution is added dropwise into solution A to perform an adsorption reaction, and stirred to obtain an active group suspension; (2) adding ammonia water dropwise to the active component suspension obtained in step (1) for a preliminary precipitation reaction, stirring for 30 min, evaporating ammonia at high temperature, controlling the pH at 5-9, and aging to obtain a precipitation precursor; (3) The precipitated precursor obtained in step (2) is filtered, washed, dried, and calcined in a nitrogen atmosphere to obtain a copper-based catalyst precursor, and then calcined at 350-800° C. for 1-12 h to obtain a copper-based composite catalyst.

2. The method for preparing a copper-based composite catalyst for producing 1,4-butanediol according to claim 1, characterized in that: The molar ratio of aluminum oxide, copper salt, zinc salt and barium salt in step (1) is: (0.05-1): 1: (0.48-1): (0.03-0.1).

3. The method for preparing a copper-based composite catalyst for producing 1,4-butanediol according to claim 1, characterized in that: In step (1), the copper salt is copper nitrate trihydrate, copper sulfate pentahydrate or copper chloride monohydrate; and the zinc salt is zinc nitrate hexahydrate, zinc sulfate heptahydrate or zinc chloride dihydrate.

4. The method for preparing a copper-based composite catalyst for producing 1,4-butanediol according to claim 1, characterized in that: The dropping in step (1) is performed while solution A is being stirred, the dropping speed is 5 mL / min, the dropping temperature is 25° C., and the stirring speed of solution A is 100-800 r / min; the stirring time in step (1) is 20 min.

5. The method for preparing a copper-based composite catalyst for producing 1,4-butanediol according to claim 1, characterized in that: The ammonia content in the ammonia water in step (2) is 1-25wt%.

6. The method for preparing a copper-based composite catalyst for producing 1,4-butanediol according to claim 1, characterized in that: The dropping in step (2) is completed under stirring conditions, and the dropping speed is 3 min / L-70 min / L.

7. The method for preparing a copper-based composite catalyst for producing 1,4-butanediol according to claim 6, characterized in that: The stirring speed is 100-800 r / min.

8. The method for preparing a copper-based composite catalyst for producing 1,4-butanediol according to claim 1, characterized in that: The aging temperature in step (2) is 25-125°C and the aging time is 2-12h.

9. The method for preparing a copper-based composite catalyst for producing 1,4-butanediol according to claim 1, characterized in that: The calcination temperature in nitrogen atmosphere in step (3) is 200-450°C and the calcination time is 2-6h.

10. Use of the catalyst according to claims 1-9 in the preparation of 1,4-butanediol, characterized in that: Used for hydrogenation of dimethyl succinate to synthesize 1,4-butanediol.

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