Catalyst for preparing 1,4-butanediol from dimethyl succinate and method of preparation
By preparing catalysts containing CuO, ZnO, Co3O4, MgO and carbon nanotubes, the problems of complex catalyst preparation and waste liquid generation were solved, achieving high active metal loading and good dispersion, and improving the selectivity and catalyst lifetime of 1,4-butanediol.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUHUAN ENG
- Filing Date
- 2023-11-17
- Publication Date
- 2026-06-23
Smart Images
Figure BDA0004555225840000071
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst production and preparation technology, specifically relating to a catalyst for the production of 1,4-butanediol from dimethyl succinate and its preparation method. Background Technology
[0002] 1,4-Butanediol (BDO) is an important organic and fine chemical raw material, widely used in pharmaceuticals, chemicals, textiles, papermaking, automobiles, and daily chemical products. BDO can be used to produce tetrahydrofuran (THF), PTEMG-spandex, polybutylene terephthalate (PBT), gamma-butyrolactone (GBL), polyurethane resin (PU Resin), polybutylene terephthalate-adipate (PBAT), coatings, plasticizers, and as a solvent and brightener in the electroplating industry.
[0003] The main industrial production processes for 1,4-butanediol include: the acetylacetonate method using formaldehyde and acetylene as raw materials; the butadiene acetoxylation method using butadiene and acetic acid as raw materials; the propylene oxide method using propylene oxide / propenol as raw materials; and the maleic anhydride method using n-butane / maleic anhydride as raw materials. The maleic anhydride method for producing 1,4-butanediol requires a catalyst, typically a copper-based catalyst. The preparation of copper-containing catalysts usually employs a co-precipitation method, where an alkaline co-precipitant, such as sodium carbonate, sodium bicarbonate, or ammonium carbonate, is added to a water-soluble copper and aluminum salt mixture. This precipitates the copper and aluminum as insoluble basic carbonates, which are then filtered, washed, dried, shaped, and calcined to obtain the catalyst.
[0004] CN103801321A discloses a Cu-Ni-Zn-MO type catalyst for preparing 1,4-butanediol, wherein M is manganese or magnesium. The preparation process is as follows: a soluble salt of Cu, Ni, Zn and M is mixed into a solution and stirred at 50-70°C with a precipitant solution. The pH value is controlled at 7-9, and the mixture is stirred for 1-3 hours. The temperature is raised to 80-90°C and aged for 2-10 hours. The precipitate is obtained by filtration, and the precipitate is washed, dried, calcined and shaped to obtain the product. CN101502803A discloses a Cu-Zn-Al-MO catalyst for the selective hydrogenation of dimethyl maleate to prepare 1,4-butanediol or tetrahydrofuran, where M is any one of Mn, Mg, or Cr. The preparation process involves co-precipitating a mixed solution of Cu, Zn, and M soluble salts with a precipitant by dropwise addition at 50–90 °C, maintaining the pH of the precipitation system at 6.8–7.2. After the addition is complete, the catalyst is aged at a constant temperature, washed, and then aluminum hydroxide and deionized water are added to the precipitate. The mixture is then stirred, heated, dried, and calcined to obtain the catalyst. The catalyst prepared by the precipitation method has the advantages of high and evenly distributed active metal loading, but its preparation process is complex, requires high process control, and generates a large amount of salt-containing waste liquid during precipitation and washing, posing environmental pressure.
[0005] Besides precipitation, impregnation is also a commonly used method for catalyst production. CN1935375A discloses a new catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. It uses mesoporous molecular sieve MCM-41 as a support to impregnate a Cu salt solution to prepare a catalyst precursor, which is then calcined to obtain a Cu / MCM-41 catalyst. Compared to precipitation, impregnation is simpler to operate, but the active metal solution aggregates and has limited metal loading capacity, thus affecting the catalyst's performance. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a catalyst and preparation method for the production of 1,4-butanediol from dimethyl succinate with high active metal loading, high dispersion and good catalytic performance.
[0007] To achieve the above objectives, the present invention provides a catalyst for the production of 1,4-butanediol from dimethyl succinate, characterized in that: the catalyst comprises, by weight percentage, CuO: 31.4–43.8 wt%, ZnO: 12.4–18.6 wt%, Co3O4: 4.1–10.9 wt%, MgO: 3.3–8.2 wt%, carbon nanotubes: 8–15 wt%, with the balance being alumina.
[0008] A method for preparing the catalyst as described above is also provided, wherein Cu salt, Zn salt, Mg salt, Co salt, carbon nanotubes and boehmite are mixed, and then an aqueous nitric acid solution is added for kneading, followed by drying and calcination to obtain the catalyst; the amount of aqueous nitric acid solution added is 1 to 4 times the total mass of Cu salt, Zn salt, Mg salt, Co salt, carbon nanotubes and boehmite.
[0009] Furthermore, the concentration of the nitric acid aqueous solution is 1 wt% to 5 wt%.
[0010] Furthermore, the kneading time is 0.5 to 3 hours.
[0011] Furthermore, the drying temperature is 80–110°C and the drying time is 3–12 hours.
[0012] Furthermore, the calcination atmosphere is one or more inert atmospheres selected from N2, CO2, and Ar, the calcination temperature is 300–550℃, the calcination time is 3–6 h, and after calcination, Cu is an active metal, Co, Zn, and Mg are auxiliary elements, and carbon nanotubes and Al2O3 are carriers.
[0013] Furthermore, the Cu salt is one or more of copper carbonate, basic copper carbonate, and copper oxalate.
[0014] Furthermore, the Zn salt is one or more of zinc carbonate, basic zinc carbonate, and zinc oxalate.
[0015] Furthermore, the Mg salt is one or more of magnesium carbonate, basic magnesium carbonate, and magnesium oxalate.
[0016] Furthermore, the Co salt is one or a mixture of two of cobalt carbonate and cobalt oxalate.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0018] 1) The catalyst of this invention uses carbonates, basic carbonates, and oxalates as raw materials. These are not easily explosive chemicals, have a short procurement cycle, and the calcination process produces no nitrogen oxide emissions. The prepared catalyst has the advantages of high active metal loading, high dispersion, and good catalytic performance.
[0019] 2) The catalyst preparation process of the present invention is mixing, drying and calcining. The preparation process is simple: no solution preparation is required, no chemical reaction is required, no washing and filtration are required, the process is easy to control, almost no saline wastewater is generated and it is easy to treat; that is, the preparation method is simple, the preparation process uses little water and is environmentally friendly.
[0020] 3) The catalyst of this invention uses Cu as the active metal. The addition of the additive can promote the more uniform dispersion of Cu atoms and the smaller the crystal grains, thereby exposing more active sites. In addition, Co is a variable valence metal that can interact with the C=O bond in the raw material ester, activate C=O, and facilitate the hydrogenation of the raw material ester to alcohol. The presence of Mg can effectively improve the acidity of the catalyst surface and inhibit the formation of tetrahydrofuran, thereby improving the selectivity of BDO. The addition range of the additives is as follows: CuO: 31.4–43.8 wt%, ZnO: 12.4–18.6 wt%, Co3O4: 4.1–10.9 wt%, MgO: 3.3–8.2 wt%. 12.4–18.6 wt% is a relatively good range for ZnO content; too little or too much will not achieve the optimal dispersion of active metal Cu. The optimal Co3O4 content is 4.1–10.9 wt%; too little will have limited auxiliary effect, while too much may trigger side reactions. The optimal MgO content is 3.3–8.2 wt%; too little will have limited effect on the acid-base regulation of the catalyst, while too much will cover the active sites and weaken the catalyst activity.
[0021] 4) The addition of carbon nanotubes improves the catalyst's ability to adsorb H2 and its "hydrogen spillover" ability, which can increase the adsorption concentration of hydrogen on the catalyst surface and the ability of H2 to move to active sites, thereby enhancing the catalyst's hydrogenation performance.
[0022] 5) The hydrogenation reaction of dimethyl succinate is exothermic. If the heat cannot be removed in time, local hot spots will form, affecting the reaction selectivity and causing the active metal crystals of the catalyst to grow and then decrease in activity. The combination of carbon nanotubes and Al2O3 channels provides high heat dissipation efficiency, avoiding the formation of local hot spots on the catalyst and effectively extending the catalyst's lifespan. Detailed Implementation
[0023] To make the objectives and advantages of the present invention clearer, the present invention will be specifically described below with reference to the embodiments. The salts used in the comparative examples and embodiments are calculated to be 100% pure.
[0024] Comparative Example
[0025] 6.81g of copper carbonate and 7.30g of boehmite were mixed evenly, and then 56g of 1wt% nitric acid aqueous solution was added for kneading for 3 hours. The mixture was then placed in a 110℃ oven for 12 hours and calcined at 500℃ for 4 hours under an inert atmosphere protected by N2. After cooling, 10g of catalyst Cu was obtained. 35 / Al2O3.
[0026] Example 1
[0027] 6.09g of basic copper carbonate, 1.62g of cobalt carbonate, 2.01g of basic zinc carbonate, 0.59g of basic magnesium carbonate, 2.56g of boehmite, and 0.80g of carbon nanotubes were mixed evenly, and then 25g of 3wt% nitric acid aqueous solution was added for kneading for 0.5h. The mixture was then placed in a 100℃ oven and dried for 12h, followed by calcination at 550℃ for 3h under a CO2 atmosphere. After cooling, 10g of catalyst Cu was obtained. 35 Co8Zn 12 Mg2 / Al2O3-8CNT.
[0028] Example 2
[0029] 4.86g of copper carbonate, 0.61g of cobalt carbonate, 1.92g of zinc carbonate, 1.73g of magnesium carbonate, 4.42g of boehmite, and 1.01g of carbon nanotubes were mixed evenly, and then 58g of 5wt% nitric acid aqueous solution was added. After kneading for 3 hours, the mixture was placed in an oven at 80℃ for 12 hours, followed by calcination at 300℃ for 6 hours under an Ar atmosphere. After cooling, the mixture was removed to obtain 10g of catalyst Cu. 25 Co3Zn 10 Mg5 / Al2O3-10CNT.
[0030] Example 3
[0031] 8.58 g of anhydrous copper acetate, 2.11 g of cobalt acetate tetrahydrate, 2.81 g of anhydrous zinc acetate, 2.34 g of magnesium acetate, 3.11 g of boehmite, and 1.30 g of carbon nanotubes were mixed evenly, and then 40 g of 1 wt% nitric acid aqueous solution was added. After kneading for 3 hours, the mixture was placed in a 100℃ oven and dried for 8 hours. Subsequently, it was calcined at 500℃ for 6 hours under a N2 atmosphere. After cooling, it was removed to obtain 10 g of catalyst Cu. 30 Co5Zn 10 Mg4 / Al2O3-13CNT.
[0032] Example 4
[0033] 5.44g of copper carbonate, 1.41g of cobalt carbonate, 2.51g of basic zinc carbonate, 0.88g of basic magnesium carbonate, 2.45g of boehmite, and 1.35g of carbon nanotubes were mixed evenly, and then 42g of 3wt% nitric acid aqueous solution was added. After kneading for 0.5h, the mixture was placed in a 90℃ oven and dried for 8h. Subsequently, it was calcined at 350℃ for 5h under a CO2 atmosphere. After cooling, it was removed to obtain 10g of catalyst Cu. 28 Co7Zn 15 Mg3 / Al2O3-13.5CNT.
[0034] Example 5
[0035] 4.52g of basic copper carbonate, 2.54g of cobalt acetate tetrahydrate, 3.65g of anhydrous zinc acetate, 1.76g of magnesium acetate, 3.46g of boehmite, and 1.20g of carbon nanotubes were mixed evenly. Then, 25g of a 1.5wt% nitric acid aqueous solution was added, and the mixture was kneaded for 1 hour. The mixture was then dried in a 100℃ oven for 6 hours, followed by calcination at 450℃ for 4 hours under an Ar atmosphere. After cooling, 10g of catalyst Cu was obtained. 26 Co6Zn 13 Mg3 / Al2O3-12CNT.
[0036] Example 6
[0037] 9.15g of anhydrous copper acetate, 1.69g of cobalt acetate tetrahydrate, 2.88g of zinc carbonate, 0.73g of basic magnesium carbonate, 2.72g of boehmite, and 1.10g of carbon nanotubes were mixed evenly. Then, 35g of a 2wt% nitric acid aqueous solution was added, and the mixture was kneaded for 1.5h. The mixture was then dried in an oven at 110℃ for 10h, followed by calcination at 500℃ for 5h under a CO2 atmosphere. After cooling, 10g of catalyst Cu was obtained. 32 Co4Zn 15 Mg 2.5 / Al2O3-11CNT.
[0038] Example 7
[0039] 4.87g of basic copper carbonate, 1.21g of cobalt carbonate, 2.30g of zinc carbonate, 2.34g of magnesium acetate, 2.70g of boehmite, and 1.49g of carbon nanotubes were mixed evenly, and then 26g of 1wt% nitric acid aqueous solution was added. After kneading for 1 hour, the mixture was placed in an oven at 110℃ for 8 hours, followed by calcination at 450℃ for 6 hours under a N2 atmosphere. After cooling, the mixture was removed to obtain 10g of catalyst Cu. 28 Co6Zn 12 Mg4 / Al2O-15CNT.
[0040] Example 8
[0041] 5.22g of basic copper carbonate, 1.00g of cobalt carbonate, 2.52g of basic zinc carbonate, 0.88g of basic magnesium carbonate, 2.65g of boehmite, and 1.50g of carbon nanotubes were mixed evenly, and then 20g of 3wt% nitric acid aqueous solution was added. After kneading for 2 hours, the mixture was placed in a 100℃ oven and dried for 9 hours. Subsequently, it was calcined at 550℃ for 3 hours under a N2 atmosphere. After cooling, it was removed to obtain 10g of catalyst Cu. 30 Co5Zn 15 Mg3 / Al2O3-12CNT.
[0042] Example 9
[0043] 5.25g of copper carbonate, 2.11g of cobalt acetate tetrahydrate, 3.08g of zinc acetate, 1.38g of magnesium carbonate, 3.68g of boehmite, and 1.11g of carbon nanotubes were mixed evenly, and then 30g of 1wt% nitric acid aqueous solution was added. After kneading for 3 hours, the mixture was placed in an oven at 80℃ for 12 hours, followed by calcination at 500℃ for 5 hours under a CO2 atmosphere. After cooling, the mixture was removed to obtain 10g of catalyst Cu. 27 Co5Zn 11 Mg4 / Al2O3-11CNT.
[0044] Example 10
[0045] 4.52g of basic copper carbonate, 3.38g of cobalt acetate tetrahydrate, 2.45g of zinc carbonate, 1.39g of magnesium carbonate, 3.44g of boehmite, and 0.80g of carbon nanotubes were mixed evenly, and then 34g of 3wt% nitric acid aqueous solution was added. After kneading for 3 hours, the mixture was placed in a 90℃ oven and dried for 10 hours. Subsequently, it was calcined at 550℃ for 3 hours under a CO2 atmosphere. After cooling, it was removed to obtain 10g of catalyst Cu. 26 Co8Zn 13 Mg4 / Al2O3-8CNT.
[0046] Example 11
[0047] The catalysts from the comparative and examples were crushed into 20-40 mesh particles and loaded into the isothermal zone of a fixed-bed reactor, supported above and below by inert components of the same particle size. The catalysts were reduced using a 10% H2-N2 atmospheric pressure mixed gas at 240°C for 12 hours. After reduction, the catalyst bed temperature was lowered to 180°C under a pure H2 atmosphere. Subsequently, the reaction pressure was increased to 6 MPa, and a dimethyl succinate methanol solution was introduced to evaluate catalyst activity. The liquid space velocity (LHSV) of the dimethyl succinate was 0.3 h⁻¹. -1 The hydrogen-to-ester ratio was 50. After the reaction stabilized, the liquid product was analyzed. Product analysis was performed using gas chromatography, with acetonitrile as an internal standard.
[0048] The performance of each catalyst is shown in Table 1.
[0049]
[0050] Lifetime experiments were conducted using the catalyst from Example 3. After 1000 hours, the DMS conversion rate was 99.2% and the BDO selectivity was 86.9%.
Claims
1. A catalyst for the production of 1,4-butanediol from dimethyl succinate, characterized in that: The catalyst comprises, by weight percentage, CuO: 31.4~43.8 wt%, ZnO: 12.4~18.6 wt%, Co3O4: 4.1~10.9 wt%, MgO: 3.3~8.2 wt%, carbon nanotubes: 8~15 wt%, with the balance being alumina; the preparation method of the catalyst is characterized by: mixing Cu salt, Zn salt, Mg salt, Co salt, carbon nanotubes and boehmite, then adding nitric acid aqueous solution for kneading, drying and calcining to obtain the catalyst; the amount of nitric acid aqueous solution added is 1~4 times the total mass of Cu salt, Zn salt, Mg salt, Co salt, carbon nanotubes and boehmite.
2. The catalyst according to claim 1, characterized in that: The concentration of the nitric acid aqueous solution is 1wt%~5wt%.
3. The catalyst according to claim 1, characterized in that: The kneading time is 0.5~3 hours.
4. The catalyst according to claim 1, characterized in that: The drying temperature is 80~110℃ and the time is 3~12h.
5. The catalyst according to claim 1, characterized in that: The calcination atmosphere is one or more inert atmospheres selected from N2, CO2, and Ar, and the calcination temperature is 300~550℃, with a calcination time of 3~6h.
6. The catalyst according to claim 1, characterized in that: The Cu salt is one or more of copper carbonate, basic copper carbonate, and copper oxalate.
7. The catalyst according to claim 1, characterized in that: The Zn salt is one or more of zinc carbonate, basic zinc carbonate, and zinc oxalate.
8. The catalyst according to claim 1, characterized in that: The Mg salt is one or more of magnesium carbonate, basic magnesium carbonate, and magnesium oxalate.
9. The catalyst according to claim 1, characterized in that: The Co salt is one or a mixture of two of cobalt carbonate and cobalt oxalate.