Method for synthesizing 1, 4-butanediamine and co-producing NMP (N-Methyl Pyrrolidone)

Abstract

The invention relates to a method for synthesizing 1, 4-butanediamine and co-producing NMP (N-Methyl Pyrrolidone), which comprises the following steps: dissolving 1, 4-butanedinitrile in a solvent, and reacting with introduced hydrogen and carbon dioxide under the action of a bi-component composite catalyst to obtain a product containing 1, 4-butanediamine, carrying out separation and purification treatment on the obtained product containing 1, 4-butanediamine to obtain 1, 4-butanediamine and NMP (N-Methyl Pyrrolidone); the active components of the bi-component composite catalyst comprise nickel salt and copper salt. According to the method disclosed by the invention, the carbon dioxide carbon source is introduced, so that the conversion of the byproduct butyrolactam into the NMP product with a high added value is realized, the combined yield of the 1, 4-butanediamine and the NMP and the conversion rate of the 1, 4-butanedinitrile are relatively high, and the economic benefit is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of organic chemical industry, and in particular to a method for synthesizing 1,4-butanediamine and co-producing NMP. Background Art

[0002] 1,4-Butanediamine is an important chemical intermediate and biochemical precursor that can be used to prepare surfactants and agricultural chemicals. It is an important raw material for synthesizing high-quality engineering plastics such as polybutylene adipamide (commonly known as nylon 46, abbreviated as PA46) and 1,4-butanediisocyanate (BDI), and has broad market prospects.

[0003] Currently, the main method for the industrial production of 1,4-butanediamine is the 1,4-butanedione hydrogenation method. This method uses 1,4-butanedione as the raw material and, in the presence of a catalyst, undergoes a hydrogenation reaction with hydrogen to produce a 1,4-butanediamine hydrogenated liquid. The hydrogenated liquid is then subjected to light removal, decoking, and vacuum distillation purification to obtain the 1,4-butanediamine product. However, the selectivity of this reaction process is difficult to accurately control, and a certain amount of butyrolactam by-product will inevitably be generated. Currently, the treatment method for these by-products is to recycle them through complex separation and purification processes, but the recovery cost is high and the economic efficiency is poor. Therefore, it is very important to develop a method for high-value utilization of by-products.

[0004] CN118005517A discloses a method for preparing 1,4-butanediamine by catalytic hydrogenation of Raney nickel. The method involves adding a carrier to the Raney nickel to produce a core-shell catalyst. 1,4-Butanediamine is then produced by adding 1,4-succinonitrile, a solvent, and the core-shell catalyst to a reactor, followed by the introduction of hydrogen gas for hydrogenation. However, the selectivity of the main product remains to be improved when preparing 1,4-butanediamine using this method.

[0005] CN119613269A discloses a method for preparing 1,4-butanediamine, comprising: a first hydrogenation reaction between a succinonitrile solution and hydrogen in the presence of a first catalyst to obtain a first hydrogenation reaction product; and a second hydrogenation reaction between the first hydrogenation reaction product and hydrogen in the presence of a second catalyst to obtain 1,4-butanediamine. The first catalyst is a nickel-based catalyst supported on Al2O3, and the second catalyst is a precious metal catalyst supported on C. This invention utilizes a stepwise hydrogenation process to prepare 1,4-butanediamine, which effectively reduces side reactions and produces fewer byproducts. However, the stepwise preparation process is complex and the operation is tedious.

[0006] Butyrolactam and N-methylpyrrolidone (NMP) are chemically related, both sharing a five-membered nitrogen-containing heterocyclic ring skeleton. Efficient conversion of butyrolactam to NMP would provide a new approach for the preparation of NMP and the utilization of the by-product butyrolactam. Given the aforementioned limitations of existing technologies, developing a process for the co-production of 1,4-butanediamine and NMP is of great practical significance. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for synthesizing 1,4-butanediamine and co-producing NMP, which realizes the co-production of 1,4-butanediamine and NMP, converts the by-product butyrolactam into a high-value-added NMP product, and improves economic benefits.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for synthesizing 1,4-butanediamine and co-producing NMP, the method comprising the following steps:

[0010] 1,4-butanediamine is dissolved in a solvent and reacted with hydrogen and carbon dioxide under the action of a two-component composite catalyst to obtain a product containing 1,4-butanediamine; the obtained product containing 1,4-butanediamine is separated and purified to obtain 1,4-butanediamine and NMP;

[0011] The active components of the two-component composite catalyst include nickel salt and copper salt.

[0012] The method for synthesizing 1,4-butanediamine and co-producing NMP provided by the present invention, by introducing carbon dioxide as a carbon source, methylating butyrolactam after hydrogenating 1,4-butanediamine, realizes the conversion of by-product butyrolactam into high value-added NMP product, forms a co-production process, and effectively overcomes the problems of waste of succinonitrile hydrogenation by-products and high cost of NMP production raw materials in traditional technology. The process route is simple and optimized, easy to operate and highly safe, can realize continuous production, greatly improves the product yield of 1,4-butanediamine and NMP, and significantly improves economic benefits. In addition, by designing a two-component composite catalyst and controlling the process conditions, the output ratio of 1,4-butanediamine and NMP can be effectively regulated, and fine regulation of each link of the reaction is achieved at the same time, with less discharge of three wastes, green and environmentally friendly, suitable for industrial production, and has good market prospects.

[0013] Preferably, the mass ratio of 1,4-succinonitrile to the solvent is 1:(2-20), for example, 1:2, 1:4, 1:5, 1:10, 1:12, 1:15 or 1:20, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] Preferably, the solvent comprises any one of ethanol, methanol or acetonitrile, preferably ethanol.

[0015] Preferably, the nickel salt comprises nickel nitrate and / or nickel chloride.

[0016] Preferably, the copper salt comprises copper acetate and / or copper chloride.

[0017] Preferably, the two-component composite catalyst is loaded in a fixed bed reactor with a loading density of 0.4-1 g / mL, for example, 0.4 g / mL, 0.6 g / mL, 0.8 g / mL, 0.9 g / mL or 1 g / mL, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 0.6-0.9 g / mL.

[0018] Preferably, the preparation method of the two-component composite catalyst includes: uniformly mixing the active component, the auxiliary agent and acetone to obtain an active component solution; immersing the carrier in the obtained active component solution, and drying, calcining and activating the solid phase obtained by solid-liquid separation to obtain the two-component composite catalyst.

[0019] Preferably, the auxiliary agent includes any one or a combination of at least two of sodium carbonate, potassium carbonate, potassium tert-butoxide or triethylamine. Typical but non-limiting combinations include a combination of sodium carbonate and potassium carbonate, a combination of potassium carbonate, potassium tert-butoxide and triethylamine, or a combination of sodium carbonate, potassium carbonate, potassium tert-butoxide and triethylamine.

[0020] Preferably, the support comprises Al2O3 and / or SiO2.

[0021] Preferably, the carrier is a sphere with a diameter of 2.5-3.5 mm, for example, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm or 3.5 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the mass ratio of the active component to acetone is 1:(2-10), for example, 1:2, 1:3, 1:5, 1:8 or 1:10, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the mass fraction of nickel salt in the active component solution to the carrier is 0.1-10%, for example, it can be 0.1%, 1%, 3%, 3.5%, 4%, 6%, 8% or 10%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 3-4%.

[0024] Preferably, the mass fraction of the copper salt in the active component solution to the carrier is 0.1-5%, for example, it can be 0.1%, 1%, 1.5%, 2%, 3%, 4% or 5%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 1-2%.

[0025] Preferably, the mass fraction of the adjuvant to the carrier in the active component solution is ≤1%, for example, it can be 1%, 0.8%, 0.5%, 0.3%, 0.2% or 0.1%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 0.2-0.5%.

[0026] Preferably, the immersion temperature is 20-50°C, for example, 20°C, 25°C, 30°C, 35°C, 40°C or 50°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 25-35°C.

[0027] Preferably, the immersion time is 10-20 hours, for example, 10 hours, 12 hours, 13 hours, 15 hours, 18 hours or 20 hours, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 10-15 hours.

[0028] Preferably, the drying temperature is 80-140°C, for example, 80°C, 90°C, 100°C, 120°C or 140°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 80-100°C.

[0029] Preferably, the drying time is 5-10 hours, for example, 5 hours, 6 hours, 7 hours, 8 hours or 10 hours, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 6-8 hours.

[0030] Preferably, the calcination temperature is 200-600°C, for example, 200°C, 300°C, 400°C, 450°C, 500°C or 600°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 400-500°C.

[0031] Preferably, the calcination time is 1-10 h, for example, 1 h, 3 h, 4 h, 5 h, 6 h, 8 h or 10 h, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 3-5 h.

[0032] Preferably, the calcination is carried out in a protective atmosphere.

[0033] Preferably, the protective atmosphere comprises nitrogen.

[0034] Preferably, the activation temperature is 200-600°C, for example, it can be 200°C, 300°C, 350°C, 400°C, 500°C or 600°C, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 300-400°C.

[0035] Preferably, the activation time is 0.5-6 h, for example, 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h or 6 h, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 2-4 h.

[0036] Preferably, the activation atmosphere comprises hydrogen.

[0037] Preferably, the molar ratio of hydrogen to carbon dioxide is (1-20):1, for example, 1:1, 3:1, 5:1, 8:1, 9:1, 10:1, 15:1 or 20:1, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably (8-10):1.

[0038] Preferably, the molar ratio of hydrogen to 1,4-succinonitrile is (1-20):1, for example, 1:1, 2:1, 5:1, 8:1, 10:1, 15:1, 18:1 or 20:1, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably (2-15):1.

[0039] Preferably, the weight hourly space velocity of 1,4-butanedionitrile in the reaction is 0.1-20h -1 , for example, it can be 0.1h -1 , 1h -1 , 5h -1 , 8h -1 , 10h -1 , 15h -1 or 20h -1 , but not limited to the listed values, other values ​​not listed in the numerical range are also applicable, preferably 5-10h -1 .

[0040] Preferably, the volume space velocity of hydrogen in the reaction is 50-100h -1 , for example, it can be 50h -1 , 60h -1 , 70h -1 , 80h -1 , 90h -1 or 100h -1 , but not limited to the listed values, other values ​​not listed in the numerical range are also applicable, preferably 60-80h -1 .

[0041] Preferably, the volume space velocity of carbon dioxide in the reaction is 50-100h -1 , for example, it can be 50h -1 , 55h -1 , 60h -1 , 80h -1 , 90h -1 or 100h -1 , but not limited to the listed values, other values ​​not listed in the numerical range are also applicable, preferably 50-60h -1 .

[0042] Preferably, the reaction temperature is 60-150°C, for example, 60°C, 80°C, 90°C, 100°C, 120°C or 150°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 80-100°C.

[0043] Preferably, the reaction pressure is 0.1-10 MPa, for example, 0.1 MPa, 1 MPa, 2 MPa, 4 MPa, 7 MPa or 10 MPa, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 1-4 MPa.

[0044] Preferably, the separation and purification process includes sequentially performing light removal, decoking and vacuum distillation.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The method for synthesizing 1,4-butanediamine and co-producing NMP provided by the present invention, by introducing carbon dioxide as a carbon source, methylating butyrolactam after hydrogenating 1,4-butanediamine, realizes the conversion of by-product butyrolactam to high value-added NMP product, forms a co-production process, and effectively overcomes the problem of waste of succinonitrile hydrogenation by-products and high cost of NMP production raw materials in traditional technology. The process route is simple and optimized, easy to operate and highly safe, and can achieve continuous production. The combined yield of 1,4-butanediamine and NMP can reach 98%, and the conversion rate of 1,4-butanediamine can reach 99%, which significantly improves economic benefits. In addition, by designing a two-component composite catalyst, temperature control and pressure regulation, it is possible to achieve fine control of each link of the reaction, with less discharge of three wastes, green and environmentally friendly, suitable for industrial production, and has good market prospects. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0048] Example 1

[0049] This embodiment provides a method for synthesizing 1,4-butanediamine and co-producing NMP, the method comprising the following steps:

[0050] A two-component composite catalyst is loaded into a fixed-bed reactor at a loading density of 0.8 g / mL. The preparation method of the two-component composite catalyst comprises: uniformly mixing nickel nitrate, copper acetate, sodium carbonate and acetone to obtain an active component solution; the mass ratio of the total mass of the nickel nitrate and copper acetate to the mass of acetone is 1:3; the mass fraction of nickel nitrate in the active component solution is 3.5% of the carrier, the mass fraction of copper acetate in the carrier is 1.5%, and the mass fraction of sodium carbonate in the carrier is 0.3%; an Al2O3 carrier with a diameter of 3 mm is impregnated in the obtained active component solution at a temperature of 30°C for 13 hours, and the obtained solid phase is filtered and dried at 90°C for 7 hours, calcined in a nitrogen atmosphere at 450°C for 4 hours, and activated in a hydrogen atmosphere at 350°C for 3 hours to obtain the two-component composite catalyst.

[0051] 1,4-butanediamine was obtained by dissolving 1,4-butanedione in ethanol at a mass ratio of 1,4-butanedione to ethanol of 1:4, and reacting with hydrogen and carbon dioxide under the action of a two-component composite catalyst at a temperature of 90°C and a pressure of 3 MPa to obtain a product containing 1,4-butanediamine; the molar ratio of hydrogen to carbon dioxide was 9:1; the molar ratio of hydrogen to 1,4-butanedione was 10:1; the weight hourly space velocity of 1,4-butanedione was 8h -1 The volumetric space velocity of hydrogen is 70h -1 The volumetric space velocity of carbon dioxide is 55h -1 The obtained product containing 1,4-butanediamine is sequentially subjected to light removal, decoking and vacuum distillation to obtain 1,4-butanediamine and NMP.

[0052] Example 2

[0053] This embodiment provides a method for synthesizing 1,4-butanediamine and co-producing NMP, the method comprising the following steps:

[0054] A two-component composite catalyst is loaded into a fixed bed reactor at a loading density of 0.6 g / mL. The preparation method of the two-component composite catalyst comprises the following steps: uniformly mixing nickel chloride, nickel nitrate, copper chloride, copper acetate, potassium tert-butoxide and acetone to obtain an active component solution; the mass ratio of the total mass of the nickel chloride, nickel nitrate, copper chloride and copper acetate to the mass of acetone is 1:3; in the active component solution, the mass fraction of nickel chloride and nickel nitrate to the carrier is 4%, the mass ratio of nickel chloride to nickel nitrate is 1:1, and the mass ratio of copper chloride to copper acetate is 1:1. The mass fraction of the carrier is 2%, the mass ratio of copper chloride to copper acetate is 1:1, and the mass fraction of potassium tert-butoxide to the carrier is 0.5%; Al2O3 and SiO2 carriers in a spherical shape with a mass ratio of 1:1 and a diameter of 2.5 mm are impregnated in the obtained active component solution, the impregnation temperature is 35°C, the time is 12h, the solid phase obtained by filtration is dried at 100°C for 6h, calcined in a nitrogen atmosphere at 500°C for 3h, and activated in a hydrogen atmosphere at 400°C for 2h to obtain the said two-component composite catalyst.

[0055] 1,4-butanediamine was obtained by dissolving 1,4-butanedione in ethanol at a mass ratio of 1,4-butanedione to ethanol of 1:5 and reacting with hydrogen and carbon dioxide under the action of a two-component composite catalyst at a temperature of 100°C and a pressure of 4 MPa. The molar ratio of hydrogen to carbon dioxide was 10:1, the molar ratio of hydrogen to 1,4-butanedione was 15:1, and the weight hourly space velocity of 1,4-butanedione was 10h -1 , the volumetric space velocity of hydrogen is 80h -1 , the volume space velocity of carbon dioxide is 60h -1 The obtained product containing 1,4-butanediamine is sequentially subjected to light removal, decoking and vacuum distillation to obtain 1,4-butanediamine and NMP.

[0056] Example 3

[0057] This embodiment provides a method for synthesizing 1,4-butanediamine and co-producing NMP, the method comprising the following steps:

[0058] A two-component composite catalyst is loaded in a fixed-bed reactor at a loading density of 0.9 g / mL. The preparation method of the two-component composite catalyst comprises: uniformly mixing nickel chloride, copper chloride, potassium carbonate and acetone to obtain an active component solution; the mass ratio of the total mass of the nickel chloride and copper chloride to the mass of acetone is 1:5; the mass fraction of nickel chloride in the active component solution is 3%, the mass fraction of copper chloride in the carrier is 1%, and the mass fraction of potassium carbonate in the carrier is 0.2%; a spherical SiO2 carrier with a diameter of 3.5 mm is immersed in the obtained active component solution at a temperature of 25°C for 15 hours, and the obtained solid phase is filtered and dried at 80°C for 8 hours, calcined in a nitrogen atmosphere at 400°C for 5 hours, and activated in a hydrogen atmosphere at 300°C for 4 hours to obtain the two-component composite catalyst.

[0059] 1,4-butanediamine was obtained by dissolving 1,4-butanedione in ethanol at a mass ratio of 1,4-butanedione to ethanol of 1:5 and reacting with hydrogen and carbon dioxide under the action of a two-component composite catalyst at a temperature of 80°C and a pressure of 2 MPa. The molar ratio of hydrogen to carbon dioxide was 8:1, and the molar ratio of hydrogen to 1,4-butanedione was 2:1. The weight hourly space velocity of 1,4-butanedione was 5h -1 , the volumetric space velocity of hydrogen is 60h -1 The volumetric space velocity of carbon dioxide is 50h -1 The obtained product containing 1,4-butanediamine is sequentially subjected to light removal, decoking and vacuum distillation to obtain 1,4-butanediamine and NMP.

[0060] Example 4

[0061] This embodiment provides a method for synthesizing 1,4-butanediamine and co-producing NMP, the method comprising the following steps:

[0062] A two-component composite catalyst is loaded into a fixed-bed reactor at a loading density of 1 g / mL. The preparation method of the two-component composite catalyst comprises: uniformly mixing nickel nitrate, copper chloride, triethylamine and acetone to obtain an active component solution; the mass ratio of the total mass of the nickel nitrate and copper chloride to the mass of acetone is 1:10; the mass fraction of nickel nitrate in the active component solution is 10% of the carrier, the mass fraction of copper chloride in the carrier is 5%, and the mass fraction of triethylamine in the carrier is 1%; an Al2O3 carrier with a diameter of 3.5 mm is impregnated in the obtained active component solution at a temperature of 50°C for 10 hours, and the obtained solid phase is filtered and sequentially dried at 140°C for 5 hours, calcined in a nitrogen atmosphere at 600°C for 1 hour, and activated in a hydrogen atmosphere at 600°C for 0.5 hours to obtain the two-component composite catalyst.

[0063] 1,4-butanediamine was obtained by dissolving 1,4-butanedione in methanol at a mass ratio of 1,4-butanedione to methanol of 1:2 and reacting with hydrogen and carbon dioxide under the action of a two-component composite catalyst at a temperature of 150°C and a pressure of 0.5 MPa. The molar ratio of hydrogen to carbon dioxide was 20:1, the molar ratio of hydrogen to 1,4-butanedione was 20:1, and the weight hourly space velocity of 1,4-butanedione was 20h -1 , the volumetric space velocity of hydrogen is 100h -1 , the volume space velocity of carbon dioxide is 100h -1 The obtained product containing 1,4-butanediamine is sequentially subjected to light removal, decoking and vacuum distillation to obtain 1,4-butanediamine and NMP.

[0064] Example 5

[0065] This embodiment provides a method for synthesizing 1,4-butanediamine and co-producing NMP, the method comprising the following steps:

[0066] A two-component composite catalyst is loaded into a fixed-bed reactor at a loading density of 0.4 g / mL. The preparation method of the two-component composite catalyst comprises: uniformly mixing nickel chloride, copper acetate, sodium carbonate and acetone to obtain an active component solution; the mass ratio of the total mass of the nickel chloride and copper acetate to the mass of acetone is 1:2; the mass fraction of nickel chloride in the active component solution is 0.1% of the carrier, the mass fraction of copper acetate in the carrier is 0.1%, and the mass fraction of sodium carbonate in the carrier is 0.8%; an Al2O3 carrier with a diameter of 2.5 mm is impregnated in the obtained active component solution at a temperature of 20°C for 20 hours, and the obtained solid phase is filtered and sequentially dried at 80°C for 10 hours, calcined in a nitrogen atmosphere at 200°C for 10 hours, and activated in a hydrogen atmosphere at 200°C for 6 hours to obtain the two-component composite catalyst.

[0067] 1,4-Butanediamine was obtained by dissolving 1,4-butanedione in acetonitrile at a mass ratio of 1,4-butanedione to acetonitrile of 1:20 and reacting with hydrogen and carbon dioxide under the action of a two-component composite catalyst at a temperature of 60°C and a pressure of 6 MPa. The molar ratio of hydrogen to carbon dioxide was 8:1, the molar ratio of hydrogen to 1,4-butanedione was 2:1, and the weight hourly space velocity of 1,4-butanediamine was 0.1 h -1 , the volumetric space velocity of hydrogen is 50h -1 The volumetric space velocity of carbon dioxide is 50h -1 The obtained product containing 1,4-butanediamine is sequentially subjected to light removal, decoking and vacuum distillation to obtain 1,4-butanediamine and NMP.

[0068] Example 6

[0069] This embodiment provides a method for synthesizing 1,4-butanediamine and co-producing NMP. The difference from Example 1 is that, except for adjusting the reaction temperature to 50° C., the rest is the same as Example 1.

[0070] Example 7

[0071] This embodiment provides a method for synthesizing 1,4-butanediamine and co-producing NMP. The difference from Example 1 is that, except for adjusting the reaction temperature to 120° C., the rest is the same as Example 1.

[0072] Example 8

[0073] This embodiment provides a method for synthesizing 1,4-butanediamine and co-producing NMP. The difference from Example 1 is that the Al2O3 carrier is replaced by irregular Al2O3 particles, and the rest is the same as Example 1.

[0074] Comparative Example 1

[0075] This comparative example provides a method for synthesizing 1,4-butanediamine and co-producing NMP. The difference from Example 1 is that copper acetate is not added to the two-component composite catalyst. The rest is the same as Example 1.

[0076] Comparative Example 2

[0077] This comparative example provides a method for synthesizing 1,4-butanediamine, which differs from Example 1 in that carbon dioxide is not introduced into the reaction, and the rest is the same as Example 1.

[0078] Comparative Example 3

[0079] This comparative example provides a method for synthesizing 1,4-butanediamine, which differs from Example 2 in that carbon dioxide is not introduced into the reaction, and the rest is the same as Example 2.

[0080] Comparative Example 4

[0081] This comparative example provides a method for synthesizing 1,4-butanediamine, which differs from Example 3 in that carbon dioxide is not introduced into the reaction, and the rest is the same as Example 3.

[0082] Comparative Example 5

[0083] This comparative example provides a method for synthesizing 1,4-butanediamine, which differs from Example 4 in that carbon dioxide is not introduced into the reaction, and the rest is the same as Example 4.

[0084] Comparative Example 6

[0085] This comparative example provides a method for synthesizing 1,4-butanediamine, which differs from Example 5 in that carbon dioxide is not introduced into the reaction, and the rest is the same as Example 5.

[0086] Comparative Example 7

[0087] This comparative example provides a method for synthesizing 1,4-butanediamine. The difference from Comparative Example 1 is that no carbon dioxide is introduced into the reaction. The rest is the same as Comparative Example 1.

[0088] The methods provided in Examples 1-8 and Comparative Example 1 were used to synthesize 1,4-butanediamine and co-produce NMP. The methods provided in Comparative Examples 2-7 were used to synthesize 1,4-butanediamine. After the reaction was carried out for 10 hours, the resulting reaction material was subjected to gas chromatography analysis. The conversion rate of 1,4-butanenitrile, the selectivity of 1,4-butanediamine, the yield of 1,4-butanediamine, the yield of NMP, the combined yield of 1,4-butanediamine and NMP, the selectivity of butyrolactam, the yield of butyrolactam, the theoretical calculation of the conversion rate of butyrolactam to NMP, the selectivity of NMP relative to butyrolactam, and the yield of NMP relative to butyrolactam were calculated by the following formulas.

[0089]

[0090] Theoretical calculations

[0091] Theoretical calculations

[0092]

[0093] Theoretically calculated yield of NMP relative to butyrolactam / % = theoretically calculated conversion of butyrolactam to NMP × selectivity of NMP relative to butyrolactam.

[0094] The results are shown in Tables 1 and 2.

[0095] Table 1

[0096]

[0097]

[0098] Table 2

[0099]

[0100] As can be seen from Table 1, the method for synthesizing 1,4-butanediamine and co-producing NMP provided by the present invention can achieve the co-production of 1,4-butanediamine and NMP, convert the by-product butyrolactam into a high-value-added NMP product, and the conversion rate of 1,4-succinonitrile and the combined yield of 1,4-butanediamine and NMP are high.

[0101] By comparing Example 1 with Examples 6 and 7, it can be seen that if the reaction temperature is too low, the conversion rate of 1,4-butanediamine will decrease, thereby affecting the combined yield of 1,4-butanediamine and NMP; if the reaction temperature is too high, the selectivity of 1,4-butanediamine will decrease, affecting its yield; by comparing Example 1 with Example 8, it can be seen that when the carrier is non-spherical, the catalytic effect will be slightly weakened and the product yield will be slightly reduced.

[0102] By comparing Example 1 with Comparative Example 1, it can be seen that the use of a single active component catalyst to synthesize 1,4-butanediamine and co-produce NMP will significantly reduce the NMP yield; by comparing Example 1 with Comparative Examples 2-7, it can be seen that if carbon dioxide is not introduced into the reaction, the NMP product cannot be co-produced.

[0103] In summary, the method for synthesizing 1,4-butanediamine and co-producing NMP provided by the present invention, by introducing a carbon dioxide carbon source, methylating butyrolactam after hydrogenating 1,4-butanediamine, realizes the conversion of by-product butyrolactam to high value-added NMP products, forms a co-production process, and effectively overcomes the waste of succinonitrile hydrogenation by-products and the high cost of NMP production raw materials in traditional technology. The process route is simple and optimized, easy to operate and highly safe, and can achieve continuous production. The combined yield of 1,4-butanediamine and NMP can reach 98%, and the conversion rate of 1,4-butanediamine can reach 99%, which significantly improves economic benefits. In addition, by designing a two-component composite catalyst, temperature control and pressure regulation, it is possible to achieve fine control of each link of the reaction, with less discharge of three wastes, green and environmentally friendly, suitable for industrial production, and has good market prospects.

[0104] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for synthesizing 1,4-butanediamine and co-producing NMP, characterized in that: The method comprises the following steps: 1,4-butanediamine is dissolved in a solvent and reacted with hydrogen and carbon dioxide under the action of a two-component composite catalyst to obtain a product containing 1,4-butanediamine; the obtained product containing 1,4-butanediamine is separated and purified to obtain 1,4-butanediamine and NMP; The active components of the two-component composite catalyst include nickel salt and copper salt.

2. The method according to claim 1, characterized in that The mass ratio of the 1,4-succinonitrile to the solvent is 1:(2-20); Preferably, the solvent comprises any one of ethanol, methanol or acetonitrile, preferably ethanol.

3. The method according to claim 1 or 2, characterized in that The nickel salt includes nickel nitrate and / or nickel chloride; Preferably, the copper salt comprises copper acetate and / or copper chloride.

4. The method according to any one of claims 1 to 3, characterized in that The two-component composite catalyst is loaded in a fixed bed reactor at a loading density of 0.4-1 g / mL, preferably 0.6-0.9 g / mL; Preferably, the preparation method of the two-component composite catalyst includes: uniformly mixing the active component, the auxiliary agent and acetone to obtain an active component solution; immersing the carrier in the obtained active component solution, and drying, calcining and activating the solid phase obtained by solid-liquid separation to obtain the two-component composite catalyst.

5. The method according to claim 4, characterized in that The auxiliary agent includes any one or a combination of at least two of sodium carbonate, potassium carbonate, potassium tert-butoxide or triethylamine; Preferably, the support comprises Al2O3 and / or SiO2; Preferably, the carrier is a sphere with a diameter of 2.5-3.5 mm.

6. The method according to claim 4 or 5, characterized in that The mass ratio of the active component to acetone is 1:(2-10); Preferably, the mass fraction of nickel salt in the active component solution to the carrier is 0.1-10%, preferably 3-4%; Preferably, the mass fraction of the copper salt in the active component solution to the carrier is 0.1-5%, preferably 1-2%; Preferably, the mass fraction of the auxiliary agent in the active component solution to the carrier is ≤1%, preferably 0.2-0.5%.

7. The method according to any one of claims 4 to 6, characterized in that The immersion temperature is 20-50°C, preferably 25-35°C; Preferably, the immersion time is 10-20 hours, preferably 10-15 hours; Preferably, the drying temperature is 80-140°C, preferably 80-100°C; Preferably, the drying time is 5-10 hours, preferably 6-8 hours.

8. The method according to any one of claims 4 to 7, characterized in that: The calcination temperature is 200-600°C, preferably 400-500°C; Preferably, the calcination time is 1-10 hours, preferably 3-5 hours; Preferably, the calcination is carried out in a protective atmosphere; Preferably, the activation temperature is 200-600°C, preferably 300-400°C; Preferably, the activation time is 0.5-6h, preferably 2-4h; Preferably, the activation atmosphere comprises hydrogen.

9. The method according to any one of claims 1 to 8, characterized in that The molar ratio of hydrogen to carbon dioxide is (1-20):1, preferably (8-10):1; Preferably, the molar ratio of hydrogen to 1,4-succinonitrile is (1-20):1, preferably (2-15):1; Preferably, the weight hourly space velocity of 1,4-butanedionitrile in the reaction is 0.1-20h -1 , preferably 5-10h -1 ; Preferably, the volume space velocity of hydrogen in the reaction is 50-100h -1 , preferably 60-80h -1 ; Preferably, the volume space velocity of carbon dioxide in the reaction is 50-100h -1 , preferably 50-60h -1 .

10. The method according to any one of claims 1 to 9, characterized in that The reaction temperature is 60-150°C, preferably 80-100°C; Preferably, the reaction pressure is 0.1-10 MPa, preferably 1-4 MPa; Preferably, the separation and purification process includes sequentially performing light removal, decoking and vacuum distillation.

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