Copper-based composite catalyst capable of regulating dimethyl succinate hydrogenation product and application of copper-based composite catalyst

Abstract

The invention discloses a copper-based composite catalyst capable of regulating and controlling dimethyl succinate hydrogenation products and application, the catalyst takes Al-doped SiO2 as a carrier to load a CuMOx composite oxide and nano metal Cu0, the molar ratio of Cu to an auxiliary agent M in the CuMOx composite oxide is (0.2-3): 1, and the auxiliary agent M is selected from any one or more of Zn, Mn, Zr, Ce, Fe, In and Ga; based on 100% of the mass of the catalyst, the mass of the nano metal Cu0 is 1%-15%, the mass of the auxiliary agent M is 5%-30%, and the mass of Al is 1%-10%. Compared with a traditional simple coprecipitation and impregnation method, the preparation process of the catalyst has the advantages that the copper active center is more dispersed, the catalyst has high reaction activity and stability, and the catalyst can be prepared by controlling the doping amount of aluminum in the carrier and the loading amount of the nano metal Cu0. And the selectivity of high value-added products gamma-butyrolactone, 1, 4-butanediol and tetrahydrofuran in the catalytic dimethyl succinate hydrogenation reaction can be effectively adjusted.

Description

Technical Field

[0001] The invention belongs to the technical field of ester hydrogenation, and particularly relates to a copper-based composite catalyst and a method for efficiently catalyzing the hydrogenation of dimethyl succinate to prepare high value-added products such as 1,4-butanediol. Background Art

[0002] 1,4-Butanediol (BDO) is a colorless, pale yellow, oily liquid that is hygroscopic and flammable, with a freezing point of 20°C. It is an aliphatic diol that can be used as a humidifier and solvent. The two hydroxyl groups of BDO are relatively active and can undergo esterification, condensation, and oxidation reactions with a variety of functional groups. Therefore, BDO is widely used in industries such as pharmaceuticals, pesticides, casting resins, textiles, chemicals, papermaking, automobiles, and daily chemicals, and is a high-quality basic chemical raw material. The largest use of BDO is in the dehydration production of tetrahydrofuran (THF), which is one of the raw materials for spandex fibers, polyurethane elastomers, and copolyester ethers. Dehydrogenation of BDO can produce γ-butyrolactone (GBL), which is not only used in the production of pharmaceuticals such as cyclopropane and pyrrolidone, but can also be used as a solvent in industrial reactions and cosmetics. In addition, BDO is also an important monomer for polybutylene terephthalate (PBT) engineering plastics, polybutylene terephthalate-adipate (PBAT) and polybutylene succinate (PBS) biodegradable plastics. It has a large market demand and broad application prospects in the future.

[0003] Currently, there are four main industrial synthesis routes for BDO: the acetylene-aldehyde method, the propylene oxide method, the butadiene method, and the maleic anhydride method. The traditional acetylene-aldehyde method (Reppe method) has been used for a long time and uses formaldehyde and acetylene as raw materials, reacting under high pressure (≥12 MPa). Although the later improved Reppe method reduced the pressure to atmospheric pressure, the calcium carbide-sourced acetylene industry has problems such as high energy consumption and high pollution. Moreover, it is a flammable and explosive gas, which limits its future development prospects. The propylene oxide method, jointly developed by Lyondell of the United States and Kuraray of Japan, catalytically isomerizes propylene oxide to produce allyl alcohol, which then undergoes hydroacylation with CO to form aldehyde allyl alcohol. Finally, BDO is obtained through extraction, hydrogenation, and refining. This process involves multiple homogeneous and heterogeneous catalytic reactions, making it not only complex and lengthy, but also produces a wide variety of byproducts. Consequently, few industrial plants have been built in China. There are two butadiene production pathways: the acetic acid process and the chlorination process. The acetic acid process involves acetyl oxidation to produce 1,4-diacetoxy-2-butene, which is then hydrogenated to 1,4-diacetoxybutane, and finally hydrolyzed to produce BDO. The chlorination process, on the other hand, produces 3,4-dichlorobutene and 1,4-dichlorobutene as intermediates, which are then hydrolyzed to produce BDO. Both butadiene production pathways face the challenges of complex processes and difficult separation and purification. Furthermore, acetic acid and chlorine corrode equipment, leading to high requirements for the discharge of three wastes. The maleic anhydride process involves oxidizing n-butane or benzene to maleic anhydride (maleic anhydride) and then hydrogenating it to produce BDO. Mitsubishi Corporation of Japan uses a nickel catalyst to directly hydrogenate maleic anhydride to GBL and tetrahydrofuran (THF), and then hydrogenates GBL to BDO over a copper catalyst. While this process is cost-effective and has a short process, it suffers from harsh reaction conditions, severe equipment corrosion, and difficulty in precise process control, resulting in a limited range of applications. The maleic anhydride esterification hydrogenation process, originally developed by Davy in the UK, involves esterifying maleic anhydride to dialkyl maleate, which is then hydrogenated to produce BDO. This process involves double bond hydrogenation over a precious metal catalyst to produce dimethyl succinate (DMS), followed by hydrogenation over a copper-based catalyst. This allows for the simultaneous production of high concentrations of BDO, GBL, and THF. The process is characterized by milder, simpler process conditions, lower investment costs, and minimal pollution. However, research has shown that DMS and BDO have high boiling points (>190°C), and the reaction is a three-phase gas-liquid-solid reaction. This leads to a higher concentration of polymers and byproducts when the copper catalyst performance deteriorates. Low temperature and high pressure favor the formation of BDO, while high temperature and low pressure favor the formation of THF and GBL. These factors make it difficult to control catalyst activity and product composition, hindering the stable operation of production equipment. Currently, copper-based catalysts used in industrial applications generally suffer from sintering deactivation, poor stability, and weak resistance to impurity interference, resulting in a lack of catalysts with superior performance.

[0004] CN1094791C discloses an improved catalyst for the catalytic hydrogenation of maleic acid, maleic anhydride or other hydrogenatable precursors to 1,4-butanediol and tetrahydrofuran, with carbon as a carrier, containing 0.1-20 weight % palladium, 0.1-20 weight % silver, 0.1-20 weight % rhenium and 0.1-5 weight % iron, and the reaction pressure is up to 2500 pounds per inch 2 , BDO selectivity is only 89.5%.

[0005] CN101502803B discloses a catalyst for selective hydrogenation of dimethyl maleate to produce 1,4-butanediol or tetrahydrofuran, and its preparation method. The catalyst is composed of Cu-Zn-Al-MO, with the molar contents of the metal elements being: copper: 30% to 60%, zinc: 10% to 50%, aluminum: 5% to 20%, and M: 0% to 10%, where M is any of Mn, Mg, or Cr. At a reaction temperature of 180°C and a H2 / dimethyl maleate (mol / mol) ratio of 200, the yield of 1,4-butanediol reaches 73.6%.

[0006] CN103566945B discloses a method for preparing a copper-manganese-aluminum heterogeneous catalyst. The catalyst, prepared by precipitating nitrate with ammonia water, achieves a maximum selectivity of 84.4% for 1,4-butanediol under reaction conditions of 185°C, 5 MPa, and a hydrogen-to-ester ratio of 200. However, using ammonia as a precipitant not only releases pungent ammonia gas during the preparation process, but also makes it difficult to completely precipitate the metal components. Summary of the Invention

[0007] In view of the problems existing in the above-mentioned prior art, the present invention provides a copper-based composite catalyst capable of regulating the hydrogenation product of dimethyl succinate.

[0008] The copper-based composite catalyst provided by the present invention is a CuMO-supported SiO2 doped with Al. x Composite oxides and nanometal Cu 0 , where CuMO x The molar ratio of Cu to the additive M in the composite oxide is 0.2 to 3:1, and the additive M is selected from any one or more of Zn, Mn, Zr, Ce, Fe, In, and Ga; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of MgO is 1% to 15%, the mass of auxiliary agent M is 5% to 30%, and the mass of Al is 1% to 10%.

[0009] Furthermore, it is preferred that the copper-based composite catalyst, based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of CuMO is 1% to 10%, the mass of the auxiliary agent M is 10% to 20%, and the mass of Al is 1% to 5%; xThe molar ratio of Cu to M in the composite oxide is 0.5 to 2.5:1.

[0010] The copper-based composite catalyst of the present invention is prepared by the following steps:

[0011] Step I: Prepare the carrier

[0012] A silicon source is dispersed in deionized water, an aluminum nitrate aqueous solution is added dropwise at 20-50°C, the pH is adjusted to 8-10 with dilute nitric acid or sodium hydroxide, and the mixture is stirred and adsorbed for 2-10 hours. A pre-dissolved template aqueous solution is then added, and the mixture is stirred at 50-80°C for 1-3 hours. The resulting mixture is sealed in an autoclave and hydrothermally reacted at 100-180°C for 6-20 hours. After the reaction, the mixture is filtered and washed with deionized water and ethanol, dried at 100-120°C for 10-12 hours, and finally calcined at 500-800°C for 4-8 hours to obtain Al-doped SiO2, which is referred to as SiO2-Al. The silicon source is any one of tetraethyl silicate, water glass, white carbon black, or sodium silicate, and the template is any one of hydroxycellulose, methylcellulose, β-cyclodextrin, sodium alginate, or sucrose.

[0013] Step II: Loading CuMO x composite oxides

[0014] At 50-90° C., the Al-doped SiO2 in step I is uniformly dispersed in deionized water, and then a mixed aqueous solution of copper nitrate, an additive M, and an aqueous solution of a precipitant are added dropwise to control the pH of the system to be 6-9. The resulting mixed slurry is stirred for 20-30 minutes, filtered and washed with deionized water until the slurry conductivity reaches 50-200 μs / cm, and the wet filter cake is completely dried at 100-120° C. to obtain a CuMO-loaded slurry. x Precursor catalyst of composite oxide, denoted as CuMO x / SiO2-Al.

[0015] Step III: Loading nanometal Cu 0 and catalyst molding

[0016] A dispersant is added to the copper nitrate aqueous solution, stirred evenly, and then impregnated onto the precursor catalyst obtained in step II. The catalyst is dried at 80-120° C. until the water content is between 30% and 50%. The catalyst is then rolled, granulated, and sieved into particles of 10-20 mesh. The particles are dried at 80-120° C. until the water content is below 10%. The particles are calcined at 300-600° C. in an air atmosphere for 2-10 hours. The particles are then formed into cylindrical particles with a diameter and height of 3 mm*3 mm to 5 mm*5 mm using a mixed graphite release agent and a radial strength of 30-100 N to obtain a finished copper-based composite catalyst, which is designated as Cu-CuMO x / SiO2-Al.

[0017] In the above step I, based on the silicon oxide in the silicon source, the mass ratio of the template to the silicon oxide in the silicon source is preferably 0.005 to 0.1:1.

[0018] In the above step II, the precipitant aqueous solution is preferably a 0.1-1.5 mol / L aqueous solution of any one of sodium carbonate, sodium hydroxide, and ammonium carbonate.

[0019] In the above step III, the dispersant is preferably any one of polyethylene glycol, polyvinyl pyrrolidone (PVP), and polyvinyl alcohol (PVA), and the molar ratio of the dispersant to copper nitrate is more preferably 0.005 to 0.2:1.

[0020] The present invention also provides an application of the copper-based composite catalyst in catalyzing the hydrogenation reaction of dimethyl succinate. The specific method is: the copper-based composite catalyst is loaded into a continuous fixed bed reactor, the catalyst is reduced with hydrogen, and the reaction mixture is heated at a mass space velocity of 0.1 to 3.0 h -1 Dimethyl succinate preheated to 90-180° C. is introduced, and hydrogen is continuously introduced, with the molar ratio of hydrogen to dimethyl succinate controlled at 30-200:1. A catalytic hydrogenation reaction is carried out at a temperature of 150-400° C. and a pressure of 2.0-10.0 MPa to obtain tetrahydrofuran (THF), γ-butyrolactone (GBL) and 1,4-butanediol (BDO).

[0021] In the above application, the preferred conditions for hydrogen reduction catalyst are: using nitrogen as carrier gas, at a pressure of 0.1-3.0 MPa, a hydrogen volume concentration of 1%-20%, and a total gas volume space velocity of 2000-10000 h -1 The temperature is raised to 160-300°C at a rate of 0.5-5°C / min and reduced for 1-24 hours.

[0022] In the above application, it is further preferred to use a mass space velocity of 0.3 to 0.8 h -1 Dimethyl succinate preheated to 100-150° C. is introduced, and pure hydrogen is continuously introduced, with the molar ratio of hydrogen to dimethyl succinate controlled at 50-150:1. A catalytic hydrogenation reaction is carried out at a temperature of 160-300° C. and a pressure of 3.0-8.0 MPa to obtain THF, GBL, and BDO.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The present invention uses Al-doped high surface area SiO2 as a carrier to load the composite oxide CuMO x (M: one or more of Zn, Mn, Zr, Ce, Fe, In, Ga) and nanometal Cu 0This method not only avoids the problems of active component aggregation and difficult structure control during traditional simple coprecipitation and impregnation preparation methods, but also provides a more dispersed copper active center, resulting in a catalyst with high reactivity and stability. Furthermore, the catalyst preparation process uses a bio-friendly template, eliminating the air pollution caused by toxic halides produced during the calcination of the quaternary ammonium salt template.

[0025] 2. The catalyst of the present invention has excellent catalytic performance in the hydrogenation reaction of dimethyl succinate, with a dimethyl succinate conversion rate of up to 99% and a total selectivity of THF, GBL and BDO greater than 98%. The selectivity of THF can be effectively adjusted by changing the Al doping amount in the carrier. When the Al doping amount increases, the catalyst has significantly higher THF selectivity. By changing the nano-metal Cu 0 The loading amount of nano-metal Cu can effectively adjust the selectivity of GBL and reduce the 0 The catalyst will produce more GBL when the loading amount is reduced, the Al doping amount is reduced, and the loading amount of higher content nanometal Cu is increased. 0 The catalyst significantly favors the production of BDO, with a BDO selectivity exceeding 92%. The catalyst ran stably for 5,000 hours with essentially unchanged activity. It boasts advantages such as high selectivity, catalyst stability, and flexible product adjustment, and has promising prospects for future industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 TEM images of the 9% Cu-Cu1Mn1Ox / SiO2-1% Al catalyst in Example 2 and the commercial CuZnAl catalyst.

[0027] Figure 2 1 is the X-ray diffraction pattern of 7% Cu-Cu1Mn1Ox / SiO2-1% Al and commercial CuZnAl catalyst after activation in Example 2. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and examples, but the protection scope of the present invention is not limited to these examples.

[0029] Example 1

[0030] 1. Preparation of copper-based composite catalyst

[0031] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuFeO x and nanometal Cu 0 , where CuFeO x It is a composite oxide with a molar ratio of Cu to Fe of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0The mass of the catalyst is 1%, the mass of Fe is 15%, and the mass of Al is 1%. The preparation method of the catalyst comprises the following steps:

[0032] Step I: Prepare the carrier

[0033] 185.8 g of tetraethyl silicate was dispersed in 500 mL of deionized water, and 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50° C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.3 g of hydroxycellulose was dissolved in 200 mL of deionized water using an ultrasonic machine to form a uniform solution, which was then added to the solution after stirring and adsorption. The mixture was stirred at 80° C. for 2 hours. The resulting mixture was sealed in an autoclave and hydrothermally reacted at 170° C. for 10 hours. After the reaction, the mixture was filtered and washed with deionized water and ethanol, dried at 120° C. for 10 hours, and finally calcined in a muffle furnace at 800° C. for 6 hours to obtain Al-doped SiO2, which was designated as SiO2-1%Al.

[0034] Step II: Loading CuFeO x composite oxides

[0035] At 80°C, under stirring, the SiO2-1% Al prepared in step I was uniformly dispersed in 500 mL of deionized water, and then 200 mL of a mixed aqueous solution containing 108.2 g of ferric nitrate, 64.7 g of copper nitrate, and a 0.2 mol / L sodium hydroxide aqueous solution were added dropwise, with the pH of the system controlled at 7. The resulting mixed slurry was stirred for 30 minutes, filtered and washed with deionized water until the slurry conductivity was less than 100 μs / cm, and the wet filter cake was dried at 120°C for 8 hours to obtain a CuFeO-loaded slurry. x The precursor catalyst of the composite oxide is denoted as Cu1Fe1O x / SiO2-1%Al.

[0036] Step III: Loading nanometal Cu 0 and catalyst molding

[0037] Add 0.16 g of polyethylene glycol (Mn=1000) to 100 mL of copper nitrate aqueous solution (containing 3.8 g (16 mmol) of copper nitrate), stir evenly, and then immerse in the Cu1Fe1O x / SiO2-1%Al, impregnated and dried at 80°C until the moisture content is between 30% and 50%, then rolled, granulated, and sieved into 10-20 mesh particles, dried in an 80°C oven until the moisture content is below 10%, transferred to a muffle furnace, and calcined at a constant temperature of 400°C in an air atmosphere at a rate of 2°C / min for 10 hours, and then beaten into cylindrical particles with a diameter and height of 3mm*3mm using a mixed graphite release agent, with a radial strength of 50N, to obtain a finished copper-based composite catalyst, recorded as 1%Cu-Cu1Fe1O x / SiO2-1%Al.

[0038] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0039] 1% Cu-Cu1Fe1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 1.0 MPa, a hydrogen volume concentration of 10%, and a total gas volume space velocity of 4500 h -1 Then, the temperature was raised to 250℃ at a rate of 3℃ / min and the reduction was carried out for 12 hours. Then, dimethyl succinate was preheated to 150℃ and heated at a mass space velocity of 0.2h -1 The catalytic hydrogenation reaction was carried out at 200°C and 7.5 MPa under a controlled molar ratio of hydrogen to dimethyl succinate (DMS) at a continuous fixed-bed reactor, switched to pure hydrogen, and conducted at a temperature of 200°C and a pressure of 7.5 MPa. The reaction products were analyzed by gas chromatography. The dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0040] Example 2

[0041] 1. Preparation of copper-based composite catalyst

[0042] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuCeO x and nanometal Cu 0 , where CuCeO x It is a composite oxide with a molar ratio of Cu to Ce of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 1%, the mass of Ce is 13%, and the mass of Al is 1%. The preparation method of the catalyst comprises the following steps:

[0043] Step I: Prepare the carrier

[0044] 265.9 g of tetraethyl silicate was dispersed in 500 mL of deionized water. 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution. The mixture was stirred and adsorbed for 2 hours. 1.2 g of β-cyclodextrin was dissolved in 200 mL of deionized water using an ultrasonicator to form a homogeneous solution. The remaining steps were the same as those in Step 1 of Example 1, yielding SiO2-1% Al.

[0045] Step II: Loading CuCeO x composite oxides

[0046] At 80°C, under stirring, the SiO2-1% Al prepared in step I was uniformly dispersed in 500 mL of deionized water. Then, 200 mL of a mixed aqueous solution containing 35.3 g of cerium nitrate and 19.7 g of copper nitrate and a 0.3 mol / L aqueous sodium hydroxide solution were added dropwise. The pH of the system was controlled to 7. The other steps of this step were the same as those in step II of Example 1 to obtain Cu1Ce1O x / SiO2-1%Al.

[0047] Step III: Loading nanometal Cu 0 and catalyst molding

[0048] This step is the same as step III of Example 1 to obtain 1% Cu-Cu1Ce1O x / SiO2-1%Al.

[0049] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0050] 1% Cu-Cu1Ce1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 1.0 MPa, a hydrogen volume concentration of 5%, and a total gas volume space velocity of 5000h -1 The temperature was raised to 220°C at a rate of 3°C / min and reduced for 12 hours. Then dimethyl succinate was preheated to 150°C and heated at a mass space velocity of 0.3h -1 The catalytic hydrogenation reaction was carried out at 200°C and 8.0 MPa under a controlled molar ratio of 160:1, using pure hydrogen as the feed gas in a continuous fixed-bed reactor. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0051] Example 3

[0052] 1. Preparation of copper-based composite catalyst

[0053] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuGaO x and nanometal Cu 0 , where CuGaO x It is a composite oxide with a molar ratio of Cu to Ga of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of Ga is 1%, the mass of Al is 1%, and the mass of Al is 1%. The preparation method of the catalyst comprises the following steps:

[0054] Step I: Prepare the carrier

[0055] 198.7 g of tetraethyl silicate was dispersed in 500 mL of deionized water. 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and adsorption was carried out with stirring for 2 hours. 1.5 g of hydroxycellulose was dissolved in 200 mL of deionized water using an ultrasonicator to form a homogeneous solution. The remaining steps were the same as those in Step 1 of Example 1, yielding SiO2-1% Al.

[0056] Step II: Loading CuGaO x composite oxides

[0057] At 80°C, under stirring, the SiO2-1% Al prepared in step I was uniformly dispersed in 500 mL of deionized water. Then, 200 mL of a mixed aqueous solution containing 58.6 g of gallium nitrate, 55.4 g of copper nitrate, and a 0.1 mol / L aqueous sodium carbonate solution were added dropwise. The pH of the system was controlled to be 7. The other steps of this step were the same as those in step II of Example 1 to obtain Cu1Ga1O x / SiO2-1%Al.

[0058] Step III: Loading nanometal Cu 0 and catalyst molding

[0059] This step is the same as step III of Example 1 to obtain 1% Cu-Cu1Ga1O x / SiO2-1%Al.

[0060] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0061] 1% Cu-Cu1Ga1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 1.0 MPa, a hydrogen volume concentration of 15%, and a total gas volume space velocity of 6000 h -1Then, the temperature was raised to 250℃ at a rate of 3℃ / min and reduced for 12 hours. Then, dimethyl succinate was preheated to 160℃ and heated at a mass space velocity of 0.2h -1 The catalytic hydrogenation reaction was carried out at 180°C and 8.0 MPa under a controlled molar ratio of 120:1, using pure hydrogen as the feed gas in a continuous fixed-bed reactor. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0062] Example 4

[0063] 1. Preparation of copper-based composite catalyst

[0064] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuZnO x and nanometal Cu 0 , where CuZnO x It is a composite oxide with a molar ratio of Cu to Zn of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of Zn is 1%, the mass of Al is 1%, and the mass of Zn is 12%. The preparation method of the catalyst comprises the following steps:

[0065] Step I: Prepare the carrier

[0066] 233.2 g of tetraethyl silicate was dispersed in 600 mL of deionized water. 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 0.8 g of sodium alginate was dissolved in 200 mL of deionized water using an ultrasonic device to form a uniform solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 1, yielding SiO2-1% Al.

[0067] Step II: Loading CuZnO x composite oxides

[0068] At 80°C, under stirring, the SiO2-1% Al prepared in step I was uniformly dispersed in 500 mL of deionized water. Then, 200 mL of a mixed aqueous solution containing 44.6 g of zinc nitrate and 55.9 g of copper nitrate and a 0.15 mol / L aqueous sodium hydroxide solution were added dropwise. The pH of the system was controlled to be 8. The other steps of this step were the same as those in step II of Example 1 to obtain Cu1Zn1O x / SiO2-1%Al.

[0069] Step III: Loading nanometal Cu 0 and catalyst molding

[0070] This step is the same as step III of Example 1 to obtain 1% Cu-Cu1Zn1O x / SiO2-1%Al.

[0071] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0072] 1% Cu-Cu1Zn1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 0.5 MPa, a hydrogen volume concentration of 10%, and a total gas volume space velocity of 6500 h -1 The temperature was raised to 220°C at a rate of 3°C / min and reduced for 10 hours. Then dimethyl succinate was preheated to 160°C and heated at a mass space velocity of 0.3h -1 The catalytic hydrogenation reaction was carried out at 190°C and 7.0 MPa under a controlled molar ratio of 160:1, using pure hydrogen as the feed gas in a continuous fixed-bed reactor. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0073] Example 5

[0074] 1. Preparation of copper-based composite catalyst

[0075] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 1%, the mass of Mn is 12%, and the mass of Al is 1%. The preparation method of the catalyst comprises the following steps:

[0076] Step I: Prepare the carrier

[0077] 210.7 g of tetraethyl silicate was dispersed in 500 mL of deionized water. 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.6 g of sucrose was dissolved in 100 mL of deionized water using an ultrasonic device to form a uniform solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 1, yielding SiO2-1% Al.

[0078] Step II: Loading CuMnO xcomposite oxides

[0079] At 80°C with stirring, the SiO2-1% Al prepared in step I was uniformly dispersed in 800 mL of deionized water. 200 mL of a mixed aqueous solution containing 39.04 g of manganese nitrate and 52.7 g of copper nitrate and a 0.1 mol / L aqueous sodium hydroxide solution were then added dropwise. The pH of the system was controlled to be 7.5. The other steps of this step were the same as those in step II of Example 1 to obtain Cu1Mn1O x / SiO2-1%Al.

[0080] Step III: Loading nanometal Cu 0 and catalyst molding

[0081] This step is the same as step III of Example 1 to obtain 1% Cu-Cu1Mn1O x / SiO2-1%Al. The pore structure parameters and dispersion results of the catalyst are shown in Table 1.

[0082] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0083] 1% Cu-Cu1Mn1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 2.0 MPa, a hydrogen volume concentration of 10%, and a total gas volume space velocity of 5000 h -1 The temperature was raised to 220°C at a rate of 3°C / min and reduced for 10 hours. Then dimethyl succinate was preheated to 160°C and heated at a mass space velocity of 0.25h -1 The catalytic hydrogenation reaction was carried out at 190°C and 7.0 MPa under a controlled molar ratio of 100:1, using pure hydrogen as the feed gas in a continuous fixed-bed reactor. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0084] Example 6

[0085] 1. Preparation of copper-based composite catalyst

[0086] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 3%, the mass of Mn is 12%, and the mass of Al is 1%. The preparation method of the catalyst comprises the following steps:

[0087] Step I: Prepare the carrier

[0088] 177.5 g of tetraethyl silicate was dispersed in 500 mL of deionized water. 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.3 g of methylcellulose was dissolved in 200 mL of deionized water using an ultrasonic device to form a uniform solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 5, yielding SiO2-1% Al.

[0089] Step II: Loading CuMnO x composite oxides

[0090] This step is the same as step II of Example 5 to obtain Cu1Mn1O x / SiO2-1%Al.

[0091] Step III: Loading nanometal Cu 0 and catalyst molding

[0092] Add 0.46 g of polyethylene glycol (Mn=1000) to 100 mL of copper nitrate aqueous solution (containing 11.3 g (46 mmol) of copper nitrate), stir evenly, and then immerse in the Cu1Mn1O x / SiO2-1%Al, the other steps of this step were the same as step III of Example 5, and the finished copper-based composite catalyst was obtained, which was recorded as 3%Cu-Cu1Mn1O x / SiO2-1%Al.

[0093] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0094] 3% Cu-Cu1Mn1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 0.5 MPa, a hydrogen volume concentration of 10%, and a total gas volume space velocity of 6000 h -1 Then, the temperature was raised to 220℃ at a rate of 3℃ / min and the reduction was carried out for 10 hours. Then, dimethyl succinate was preheated to 160℃ and the mass space velocity was 0.2h -1 The catalytic hydrogenation reaction was carried out at 180°C and 7.0 MPa under a controlled molar ratio of hydrogen to dimethyl succinate (DMS) at a continuous fixed-bed reactor, switched to pure hydrogen, and the reaction was conducted. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0095] Example 7

[0096] 1. Preparation of copper-based composite catalyst

[0097] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 5%, the mass of Mn is 13%, and the mass of Al is 1%. The preparation method of the catalyst comprises the following steps:

[0098] Step I: Prepare the carrier

[0099] 170.5 g of tetraethyl silicate was dispersed in 500 mL of deionized water. 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.2 g of methylcellulose was dissolved in 200 mL of deionized water using an ultrasonic device to form a uniform solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 5, yielding SiO2-1% Al.

[0100] Step II: Loading CuMnO x composite oxides

[0101] This step is the same as step II of Example 5 to obtain Cu1Mn1O x / SiO2-1%Al.

[0102] Step III: Loading nanometal Cu 0 and catalyst molding

[0103] Add 0.77 g of polyethylene glycol (Mn=1000) to 100 mL of copper nitrate aqueous solution (containing 18.7 g (77 mmol) of copper nitrate), stir evenly, and then immerse in the Cu1Mn1O x / SiO2-1%Al, the other steps of this step are the same as step III of Example 5 to obtain 5%Cu-Cu1Mn1O x / SiO2-1%Al.

[0104] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0105] 5% Cu-Cu1Mn1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor, with nitrogen as carrier gas, at a pressure of 0.5 MPa, a hydrogen volume concentration of 10%, and a total gas volume space velocity of 7000 h -1 The temperature was raised to 220°C at a rate of 3°C / min and reduced for 10 hours. Then dimethyl succinate was preheated to 150°C and heated at a mass space velocity of 0.2h -1 The catalytic hydrogenation reaction was carried out at 190°C and 7.0 MPa under a controlled molar ratio of hydrogen to dimethyl succinate (DMS) at a continuous fixed-bed reactor, switched to pure hydrogen, and the reaction was carried out at 190°C and a pressure of 7.0 MPa. The reaction products were analyzed by gas chromatography. The dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0106] Example 8

[0107] 1. Preparation of copper-based composite catalyst

[0108] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 7%, the mass of Mn is 13%, and the mass of Al is 1%. The preparation method of the catalyst comprises the following steps:

[0109] Step I: Prepare the carrier

[0110] 163.6 g of tetraethyl silicate was dispersed in 500 mL of deionized water. 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.1 g of methylcellulose was dissolved in 200 mL of deionized water using an ultrasonic device to form a uniform solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 5, yielding SiO2-1% Al.

[0111] Step II: Loading CuMnO x composite oxides

[0112] This step is the same as step II of Example 5 to obtain Cu1Mn1O x / SiO2-1%Al.

[0113] Step III: Loading nanometal Cu 0 and catalyst molding

[0114] Add 1.53 g of polyethylene glycol (Mn=1000) to 100 mL of copper nitrate aqueous solution (containing 26.4 g (109 mmol) of copper nitrate), stir evenly, and then immerse in the Cu1Mn1O x / SiO2-1%Al, the other steps of this step are the same as step III of Example 5 to obtain 7%Cu-Cu1Mn1O x / SiO2-1%Al.

[0115] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0116] 7% Cu-Cu1Mn1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 1.0 MPa, a hydrogen volume concentration of 15%, and a total gas volume space velocity of 7000 h -1 Then, the temperature was raised to 220℃ at a rate of 3℃ / min and the reduction was carried out for 10 hours. Then, dimethyl succinate was preheated to 180℃ and the mass space velocity was 0.3h -1 The catalytic hydrogenation reaction was carried out at 180°C and 7.5 MPa under a controlled molar ratio of hydrogen to dimethyl succinate (DMS) at a continuous fixed-bed reactor, switched to pure hydrogen, and conducted at a temperature of 180°C and a pressure of 7.5 MPa. The reaction products were analyzed by gas chromatography. The dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0117] Example 9

[0118] 1. Preparation of copper-based composite catalyst

[0119] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 9%, the mass of Mn is 13%, and the mass of Al is 1%. The preparation method of the catalyst comprises the following steps:

[0120] Step I: Prepare the carrier

[0121] 156.5 g of tetraethyl silicate was dispersed in 500 mL of deionized water. 200 mL of a 0.18 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.0 g of methylcellulose was dissolved in 200 mL of deionized water using an ultrasonic device to form a uniform solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 5, yielding SiO2-1% Al.

[0122] Step II: Loading CuMnO x composite oxides

[0123] This step is the same as step II of Example 5 to obtain Cu1Mn1O x / SiO2-1%Al.

[0124] Step III: Loading nanometal Cu 0 and catalyst molding

[0125] Add 2.5 g of polyethylene glycol (Mn=1000) to 100 mL of copper nitrate aqueous solution (containing 34.0 g (141 mmol) of copper nitrate), stir evenly, and then immerse in the Cu1Mn1O x / SiO2-1%Al, the other steps of this step were the same as step III of Example 5, and the finished copper-based composite catalyst was obtained, which was recorded as 9%Cu-Cu1Mn1O x / SiO2-1%Al. The pore structure parameters and dispersion results of the catalyst are shown in Table 1.

[0126] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0127] 9% Cu-Cu1Mn1O x / SiO2-1%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 1.0 MPa, a hydrogen volume concentration of 5%, and a total gas volume space velocity of 8000 h -1 Then, the temperature was raised to 230℃ at a rate of 3℃ / min and reduced for 8 hours. Then, dimethyl succinate was preheated to 150℃ and heated at a mass space velocity of 0.3h -1 The catalytic hydrogenation reaction was carried out at 190°C and 8.0 MPa under a controlled molar ratio of 120:1, using pure hydrogen as the feed gas in a continuous fixed-bed reactor. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0128] Example 10

[0129] 1. Preparation of copper-based composite catalyst

[0130] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1.5:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 7%, the mass of Mn is 13%, and the mass of Al is 2%. The preparation method of the catalyst comprises the following steps:

[0131] Step I: Prepare the carrier

[0132] 140.0 g of tetraethyl silicate was dispersed in 500 mL of deionized water. 200 mL of a 0.37 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.2 g of hydroxycellulose was dissolved in 200 mL of deionized water using an ultrasonic device to form a uniform solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 9, yielding SiO2-2% Al.

[0133] Step II: Loading CuMnO x composite oxides

[0134] At 80°C, under stirring, the SiO2-2% Al prepared in step I was uniformly dispersed in 500 mL of deionized water. 200 mL of a mixed aqueous solution containing 42.3 g of manganese nitrate and 85.6 g of copper nitrate and a 0.2 mol / L aqueous sodium hydroxide solution were then added dropwise. The pH of the system was controlled to be 7.5. The other steps were the same as those in step II of Example 9 to obtain Cu 1.5 Mn1O x / SiO2-2%Al.

[0135] Step III: Loading nanometal Cu 0 and catalyst molding

[0136] Add 2.53 g of polyethylene glycol (Mn=1000) to 100 mL of copper nitrate aqueous solution (containing 34.0 g (141 mmol) of copper nitrate), stir evenly and then immerse in the Cu2O3 solution obtained in step II. 1.5 Mn1O x / SiO2-2%Al, the other steps of this step are the same as step III of Example 9 to obtain 7%Cu-Cu 1.5 Mn1O x / SiO2-2%Al.

[0137] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0138] 7% Cu-Cu 1.5 Mn1O x / SiO2-2%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 1.0 MPa, a hydrogen volume concentration of 10%, and a total gas volume space velocity of 7000 h -1 Then, the temperature was raised to 220℃ at a rate of 3℃ / min and the reduction was carried out for 10 hours. Then, dimethyl succinate was preheated to 150℃ and heated at a mass space velocity of 0.13h -1 The catalytic hydrogenation reaction was carried out at 190°C and 8.0 MPa under a controlled molar ratio of 160:1, using pure hydrogen as the feed gas in a continuous fixed-bed reactor. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0139] Example 11

[0140] 1. Preparation of copper-based composite catalyst

[0141] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1.5:1; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 7%, the mass of Mn is 13%, and the mass of Al is 4%. The preparation method of the catalyst comprises the following steps:

[0142] Step I: Prepare the carrier

[0143] 126.7 g of tetraethyl silicate was dispersed in 300 mL of deionized water. 200 mL of a 0.74 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.1 g of hydroxycellulose was dissolved in 200 mL of deionized water using an ultrasonic device to form a uniform solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 10, yielding SiO2-4%Al.

[0144] Step II: Loading CuMnO x composite oxides

[0145] At 80°C, under stirring, the SiO2-4% Al prepared in step I was uniformly dispersed in 500 mL of deionized water. 200 mL of a mixed aqueous solution containing 42.2 g of manganese nitrate and 85.6 g of copper nitrate and a 0.2 mol / L aqueous sodium hydroxide solution were then added dropwise. The pH of the system was controlled to be 7.5. The other steps of this step were the same as those in step II of Example 10 to obtain Cu 1.5 Mn1O x / SiO2-4%Al.

[0146] Step III: Loading nanometal Cu 0 and catalyst molding

[0147] This step is the same as step III of Example 10 to obtain 7% Cu-Cu 1.5 Mn1O x / SiO2-4%Al.

[0148] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0149] 7% Cu-Cu 1.5 Mn1O x / SiO2-4%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 0.5 MPa, a hydrogen volume concentration of 5%, and a total gas volume space velocity of 7000 h -1 Then, the temperature was raised to 220℃ at a rate of 3℃ / min and the reduction was carried out for 9 hours. Then, dimethyl succinate was preheated to 150℃ and heated at a mass space velocity of 0.15h -1 The catalytic hydrogenation reaction was carried out at 200°C and 7.5 MPa under a controlled molar ratio of hydrogen to dimethyl succinate (DMS) at a continuous fixed-bed reactor, switched to pure hydrogen, and conducted at a temperature of 200°C and a pressure of 7.5 MPa. The reaction products were analyzed by gas chromatography. The dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0150] Example 12

[0151] 1. Preparation of copper-based composite catalyst

[0152] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1:2; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 7%, the mass of Mn is 13%, and the mass of Al is 6%. The preparation method of the catalyst comprises the following steps:

[0153] Step I: Prepare the carrier

[0154] 177.2 g of tetraethyl silicate was dispersed in 300 mL of deionized water. 200 mL of a 1.1 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution, and the mixture was stirred and adsorbed for 2 hours. 1.2 g of hydroxycellulose was dissolved in 200 mL of deionized water using an ultrasonic device to form a homogeneous solution, which was then added to the solution after stirring and adsorption. The remaining steps were the same as those in Step 1 of Example 10, yielding SiO2-6%Al.

[0155] Step II: Loading CuMnO x composite oxides

[0156] At 80°C with stirring, the SiO2-6% Al prepared in step I was uniformly dispersed in 700 mL of deionized water. Then, 200 mL of a mixed aqueous solution containing 42.3 g of manganese nitrate and 28.6 g of copper nitrate and a 0.3 mol / L aqueous sodium hydroxide solution were added dropwise. The pH of the system was controlled to 7. The other steps of this step were the same as those in step II of Example 10 to obtain Cu1Mn2O x / SiO2-6%Al.

[0157] Step III: Loading nanometal Cu 0 and catalyst molding

[0158] This step is the same as step III of Example 10 to obtain 7% Cu-Cu1Mn2O x / SiO2-6%Al.

[0159] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0160] 7% Cu-Cu1Mn2O x / SiO2-6%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 1.0 MPa, a hydrogen volume concentration of 15%, and a total gas volume space velocity of 6000 h -1 The temperature was raised to 230°C at a rate of 3°C / min and reduced for 10 hours. Then dimethyl succinate was preheated to 150°C and heated at a mass space velocity of 0.2h -1 The catalytic hydrogenation reaction was carried out at 190°C and 8.0 MPa under a controlled molar ratio of 160:1, using pure hydrogen as the feed gas in a continuous fixed-bed reactor. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0161] Example 13

[0162] The copper-based composite catalyst of this embodiment is based on Al-doped SiO2 as a carrier to load CuMnO x and nanometal Cu 0 , where CuMnO x It is a composite oxide with a molar ratio of Cu to Mn of 1:2; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of the catalyst is 7%, the mass of Mn is 13%, and the mass of Al is 8%. The preparation method of the catalyst comprises the following steps:

[0163] Step I: Prepare the carrier

[0164] 166.0 g of tetraethyl silicate was dispersed in 600 mL of deionized water. 200 mL of a 1.48 mol / L aqueous aluminum nitrate solution was added dropwise at 50°C. The pH was then adjusted to 9 with a 0.2 mol / L aqueous sodium hydroxide solution. The mixture was stirred and adsorbed for 2 hours. The remaining steps were the same as those in Step 1 of Example 12 to obtain SiO2-8% Al.

[0165] Step II: Loading CuMnO x composite oxides

[0166] This step is the same as step II of Example 12 to obtain Cu1Mn2O x / SiO2-8%Al.

[0167] Step III: Loading nanometal Cu 0 and catalyst molding

[0168] This step is the same as step III of Example 12 to obtain 7% Cu-Cu1Mn2O x / SiO2-8%Al. The pore structure parameters and dispersion results of the catalyst are shown in Table 1.

[0169] 2. Application of copper-based composite catalyst in the hydrogenation reaction of dimethyl succinate

[0170] 7% Cu-Cu1Mn2O x / SiO2-8%Al was loaded into a continuous fixed bed reactor with nitrogen as carrier gas, at a pressure of 1.0 MPa, a hydrogen volume concentration of 10%, and a total gas volume space velocity of 7000 h -1 Then, the temperature was raised to 220℃ at a rate of 3℃ / min and the reduction was carried out for 10 hours. Then, dimethyl succinate was preheated to 150℃ and heated at a mass space velocity of 0.18h -1The catalytic hydrogenation reaction was carried out at 180°C and 8.0 MPa under a controlled molar ratio of 160:1, using pure hydrogen as the feed gas in a continuous fixed-bed reactor. The reaction products were analyzed by gas chromatography, and the dimethyl succinate conversion and selectivities for THF, GBL, and BDO are shown in Table 2.

[0171] Table 1

[0172]

[0173] Table 2

[0174]

Claims

1. A copper-based composite catalyst capable of regulating the hydrogenation product of dimethyl succinate, characterized in that: The catalyst is Al-doped SiO2 as a carrier to load CuMO x Composite oxides and nanometal Cu 0 , where CuMO x The molar ratio of Cu to the additive M in the composite oxide is 0.2 to 3:1, and the additive M is selected from any one or more of Zn, Mn, Zr, Ce, Fe, In, and Ga; based on the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of is 1% to 15%, the mass of the additive M is 5% to 30%, and the mass of Al is 1% to 10%; The catalyst is prepared by the following steps: Step I: Prepare the carrier The silicon source is dispersed in deionized water, and an aluminum nitrate aqueous solution is added dropwise at 20-50°C. The pH is then adjusted to 8-10 with dilute nitric acid or sodium hydroxide, and the mixture is stirred and adsorbed for 2-10 hours. An aqueous template solution dissolved in advance is then added, and the mixture is stirred at 50-80°C for 1-3 hours. The resulting mixture is sealed in a high-pressure reactor and subjected to a hydrothermal reaction at 100-180°C for 6-20 hours. After the reaction, the mixture is filtered and washed with deionized water and ethanol, dried at 100-120°C for 10-12 hours, and finally calcined at 500-800°C for 4-8 hours to obtain Al-doped SiO2, which is referred to as SiO2-Al. The silicon source is any one of tetraethyl silicate, water glass, white carbon black or sodium silicate; The template is any one of hydroxycellulose, methylcellulose, β-cyclodextrin, sodium alginate, and sucrose; Step II: Loading CuMO x composite oxides At 50-90° C., the Al-doped SiO2 in step I is uniformly dispersed in deionized water, and then a mixed aqueous solution of copper nitrate, an additive M, and an aqueous solution of a precipitant are added dropwise to control the pH of the system to be 6-9. The resulting mixed slurry is stirred for 20-30 minutes, filtered and washed with deionized water until the slurry conductivity reaches 50-200 μs / cm, and the wet filter cake is completely dried at 100-120° C. to obtain a CuMO-loaded slurry. x Precursor catalyst of composite oxide, denoted as CuMO x / SiO2-Al; Step III: Loading nanometal Cu 0 and catalyst molding A dispersant is added to the copper nitrate aqueous solution, stirred evenly, and then impregnated onto the precursor catalyst obtained in step II. The catalyst is dried at 80-120° C. until the water content is between 30% and 50%. The catalyst is then rolled, granulated, and sieved into particles of 10-20 mesh. The particles are dried at 80-120° C. until the water content is below 10%. The particles are calcined at 300-600° C. in an air atmosphere for 2-10 hours. The particles are then formed into cylindrical particles with a diameter and height of 3 mm*3 mm to 5 mm*5 mm using a mixed graphite release agent and a radial strength of 30-100 N to obtain a finished copper-based composite catalyst, which is designated as Cu-CuMO x / SiO2-Al.

2. The copper-based composite catalyst for regulating the dimethyl succinate hydrogenation product according to claim 1, wherein: Taking the mass of the catalyst as 100%, the nano-metal Cu 0 The mass of CuMO is 1% to 10%, the mass of the auxiliary agent M is 10% to 20%, and the mass of Al is 1% to 5%; x The molar ratio of Cu to M in the composite oxide is 0.5 to 2.5:

1.

3. The copper-based composite catalyst for regulating the dimethyl succinate hydrogenation product according to claim 1 or 2, characterized in that: In step I, based on the silicon oxide in the silicon source, the mass ratio of the template to the silicon oxide in the silicon source is 0.005 to 0.1:

1.

4. The copper-based composite catalyst for regulating the dimethyl succinate hydrogenation product according to claim 1 or 2, characterized in that: In step II, the precipitant aqueous solution is a 0.1-1.5 mol / L aqueous solution of any one of sodium carbonate, sodium hydroxide, and ammonium carbonate.

5. The copper-based composite catalyst for regulating the dimethyl succinate hydrogenation product according to claim 1 or 2, characterized in that: In step III, the dispersant is any one of polyethylene glycol, polyvinyl pyrrolidone, and polyvinyl alcohol.

6. The copper-based composite catalyst capable of regulating the dimethyl succinate hydrogenation product according to claim 5, characterized in that: In step III, the molar ratio of the dispersant to copper nitrate is 0.005 to 0.2:

1.

7. Use of the copper-based composite catalyst according to claim 1 in catalyzing the hydrogenation reaction of dimethyl succinate, characterized in that: The copper-based composite catalyst is loaded into a continuous fixed bed reactor, and the catalyst is reduced with hydrogen at a mass space velocity of 0.1 to 3.0 h -1 Dimethyl succinate preheated to 90-180° C. is introduced, and hydrogen is continuously introduced, with the molar ratio of hydrogen to dimethyl succinate controlled at 30-200:

1. A catalytic hydrogenation reaction is carried out at a temperature of 150-400° C. and a pressure of 2.0-10.0 MPa to obtain tetrahydrofuran, γ-butyrolactone and 1,4-butanediol.

8. The use of the copper-based composite catalyst according to claim 7 in catalyzing the hydrogenation reaction of dimethyl succinate, characterized in that: The conditions for hydrogen reduction catalyst are: using nitrogen as carrier gas, at a pressure of 0.1-3.0 MPa, a hydrogen volume concentration of 1%-20%, and a total gas volume space velocity of 2000-10000 h -1 The temperature is raised to 160-300°C at a rate of 0.5-5°C / min and reduced for 1-24 hours.

9. The use of the copper-based composite catalyst according to claim 7 in catalyzing the hydrogenation reaction of dimethyl succinate, characterized in that: With mass air velocity of 0.3~0.8h -1 Dimethyl succinate preheated to 100-150° C. is introduced, and pure hydrogen is continuously introduced, with the molar ratio of hydrogen to dimethyl succinate controlled at 50-150:

1. A catalytic hydrogenation reaction is carried out at a temperature of 160-300° C. and a pressure of 3.0-8.0 MPa to obtain tetrahydrofuran, γ-butyrolactone and 1,4-butanediol.

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