Preparation method of 1, 4-butanediamine

Abstract

The invention provides a preparation method of 1, 4-butanediamine. The preparation method comprises the following steps: carrying out a first hydrogenation reaction on a succinonitrile solution and hydrogen under the catalysis of a first catalyst to obtain a first hydrogenation reaction product; carrying out second hydrogenation reaction on the first hydrogenation reaction product and hydrogen under the catalysis of a second catalyst to obtain 1, 4-butanediamine; wherein the first catalyst is a nickel-based catalyst loaded on Al2O3, and the second catalyst is a noble metal catalyst loaded on C. According to the present invention, the step-by-step hydrogenation method is adopted, the corresponding catalyst is utilized, the hydrogenation depth is controllable, the amino butyronitrile is mainly generated in the first step, and the 1, 4-butanediamine is prepared through the further hydrogenation in the second step, such that the side reaction can be effectively reduced, the produced by-product is less, the separation difficulty is low during the post-treatment, and the product purity is high. The method does not need to add other components such as ammonia gas to inhibit side reaction, and is simple in industrial process flow and easy to popularize and use.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a method for preparing 1,4-butanediamine. Background Art

[0002] 1,4-Butanediamine, also known as putrescine, is a colorless crystal or colorless to slightly yellow liquid at room temperature with a strong pungent odor. It is an important organic synthesis intermediate and is widely used in medicine, nylon plastics, pesticides and biological fields. With the expansion of downstream applications, especially the increasing demand for high-performance materials such as nylon 46 and PA4T, the downstream market prospects of 1,4-butanediamine are broad.

[0003] At present, the synthesis of 1,4-butanediamine is mainly divided into biological method and chemical method. Among them, the research on the biological method of preparing 1,4-butanediamine mainly focuses on transforming the metabolic process of engineering strains and combining fermentation methods to obtain more target products. The main method is to convert arginine into 1,4-butanediamine and ornithine under the catalysis of arginine decarboxylase. Ornithine is selectively converted into the target product under the action of ornithine decarboxylase. However, the microbial culture conditions of the biological method are relatively harsh, and the fermentation environment is also relatively special. Due to its own defects, the biological method takes a long time to generate the target product, has low production efficiency, and unstable product quality.

[0004] The chemical method for preparing butanediamine is mainly through the catalytic hydrogenation of succinonitrile. There are also a few patents that mention the preparation of butanediamine using succinic acid / butanediol as raw materials.

[0005] Patent publication CN117088779A uses succinonitrile as raw material and Raney cobalt doped with other metals as catalyst. Hydrogen and ammonia are introduced into the process to prepare diaminobutane by one-step hydrogenation. This process adds an inhibitor - ammonia to reduce the occurrence of side reactions, but the introduction of ammonia into the hydrogenation process affects the hydrogenation efficiency. At the same time, it has high requirements for equipment and is difficult to implement industrially. Patent publication CN117658820 A uses synthesis gas and acrylonitrile as raw materials to synthesize cyanopropionaldehyde, and performs ammoniation and hydrogenation of cyanopropionaldehyde to co-produce 1,3-butanediamine and 1,4-butanediamine. This process involves acrylonitrile, a highly toxic substance, and has high requirements for the device. In addition, the co-production involves two products, which are difficult to separate.

[0006] Therefore, how to provide a preparation method of 1,4-butanediamine with high yield, less by-products and easy industrial promotion is very important for the marketization of 1,4-butanediamine. Summary of the invention

[0007] The main purpose of the present invention is to provide a method for preparing 1,4-butanediamine, so as to solve the problem of high by-product content when preparing 1,4-butanediamine in the prior art.

[0008] In order to achieve the above-mentioned object, according to the first aspect of the present invention, a method for preparing 1,4-butanediamine is provided, the method comprising: a first hydrogenation reaction is carried out between a succinonitrile solution and hydrogen under the catalysis of a first catalyst to obtain a first hydrogenation reaction product; and a second hydrogenation reaction is carried out between the first hydrogenation reaction product and hydrogen under the catalysis of a second catalyst to obtain 1,4-butanediamine; wherein the first catalyst is a nickel-based catalyst supported on Al2O3, and the second catalyst is a precious metal catalyst supported on C.

[0009] Furthermore, the loading amount of the nickel-based metal in the first catalyst is 10-30% by mass fraction, preferably 20-30%; preferably, the nickel-based metal also includes other metals besides nickel, wherein the other metals are selected from one or more of the following: Cr, Mo or Ti; preferably, the other metals in the nickel-based metal are Cr or Mo; preferably, the metal composition in the nickel-based metal is, by mass fraction: Ni: 90-98%; Cr: 0-5%; Mo: 0-5%; Ti: 0-5%.

[0010] Furthermore, the precious metal in the second catalyst includes: Pt or Pd; preferably, the precious metal content in the second catalyst is 0.5-1% by mass fraction.

[0011] Furthermore, the concentration of succinonitrile in the succinonitrile solution is 10-50% by mass, preferably 15-25%.

[0012] Further, the solvent of the succinonitrile solution is selected from one or more of the following: methanol, ethanol or water; preferably, the solvent of the succinonitrile solution is methanol.

[0013] Furthermore, the dosage of the first catalyst is 0.1-5 times, preferably 0.5-1 times, the mass of succinonitrile in the succinonitrile solution.

[0014] Further, the temperature of the first hydrogenation reaction is 80-150°C, preferably 90-110°C; preferably, the time of the first hydrogenation reaction is 1-5h, preferably 2-3h; preferably, the pressure of the first hydrogenation reaction is 0.5-2.5MPa, preferably 1-1.5MPa.

[0015] Furthermore, the dosage of the second catalyst is 0.01-0.3 times, preferably 0.05-0.1 times, the mass of succinonitrile in the succinonitrile solution.

[0016] Further, the temperature of the second hydrogenation reaction is 70-120°C, preferably 80-90°C; preferably, the time of the second hydrogenation reaction is 0.1-3h, preferably 0.5-1h; preferably, the pressure of the second hydrogenation reaction is 0.5-1.5MPa, preferably 0.7-1.0MPa.

[0017] Furthermore, the reactants for the first hydrogenation reaction are fed from the upper end of the first reactor, and the first hydrogenation reaction product is discharged from the lower end of the first reactor; the first hydrogenation reaction product is fed from the upper end of the second reactor, and the second hydrogenation reaction product is discharged from the lower end of the second reactor.

[0018] The technical solution of the present invention is applied, a step-by-step hydrogenation method is adopted, and a corresponding catalyst is used, and the depth of hydrogenation is controllable. The first step mainly generates aminobutyronitrile, and the second step further hydrogenates to prepare 1,4-butanediamine, which can effectively reduce side reactions, produce fewer by-products, and have low separation difficulty during post-processing, and high product purity. In addition, the method does not need to add other components such as ammonia to inhibit side reactions, and the industrial process flow is simple and easy to promote and use. DETAILED DESCRIPTION

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0020] As mentioned in the background technology, the prior art has certain defects in the preparation of 1,4-butanediamine, whether it is a biological method or a chemical method. For example, the biological method has special environmental requirements for fermentation culture, low production efficiency, and unstable product quality; the chemical method also generates a certain amount of by-products and is not easy to industrialize. Therefore, this application intends to propose a preparation method of 1,4-butanediamine that can reduce the by-product content and is easy to promote industrial production.

[0021] In a first typical embodiment of the present application, a method for preparing 1,4-butanediamine is provided, the method comprising: a first hydrogenation reaction of a succinonitrile solution and hydrogen under the catalysis of a first catalyst to obtain a first hydrogenation reaction product; a second hydrogenation reaction of the first hydrogenation reaction product and hydrogen under the catalysis of a second catalyst to obtain 1,4-butanediamine; wherein the first catalyst is a nickel-based catalyst supported on Al2O3, and the second catalyst is a precious metal catalyst supported on C.

[0022] The chemical equation of the first hydrogenation reaction is as follows: (the catalyst 1# in the following formula is the first catalyst);

[0023]

[0024] The chemical equation of the second hydrogenation reaction is as follows: (the catalyst 2# in the following formula is the second catalyst);

[0025]

[0026] The present application utilizes a suitable catalyst to control the degree of hydrogenation of the reactants, and controls the reaction for preparing 1,4-butanediamine to be carried out in two steps. Among them, the first hydrogenation reaction utilizes a nickel-based catalyst, which has a low catalytic activity and mainly generates an aminobutanenitrile intermediate, which can avoid overreaction. The second hydrogenation reaction utilizes a precious metal catalyst, which has a high catalytic activity, and finally completes the catalytic synthesis of butanediamine. Through the above two hydrogenation reactions, the occurrence of side reactions can be effectively reduced without adding other components such as ammonia to suppress side reactions, and the selectivity is high. At the same time, the separation difficulty of post-treatment is reduced, and the purity of the obtained 1,4-butanediamine is high.

[0027] The chemical equation of the possible side reaction in this application is as follows: (the byproducts are mainly tetrahydropyrrole and ditetramethyltriamine)

[0028]

[0029] The conversion rate of succinonitrile in the first hydrogenation reaction is: (100-succinonitrile content)*100%, the selectivity of the first hydrogenation reaction is calculated as: (100-tetrahydropyrrole content-bistetramethyltriamine content)*100%, and the yield is: conversion rate*selectivity.

[0030] The conversion rate of aminobutyronitrile in the second hydrogenation reaction is: (100-aminobutyronitrile content)*100%, the selectivity of the second hydrogenation reaction is calculated as: (100-tetrahydropyrrole content-bistetramethyltriamine content)*100%, and the yield is: conversion rate*selectivity.

[0031] The substance contents are all the gas spectrum normalized contents after deducting the solvent. The higher the selectivity, the less the by-product content of the reaction.

[0032] In order to further convert all the products into aminobutyronitrile in the first hydrogenation reaction and reduce the occurrence of side reactions, in a preferred embodiment, the loading amount of the nickel-based metal in the first catalyst is 10-30% by mass fraction, preferably 20-30%; preferably, the nickel-based metal also includes other metals other than nickel, wherein the other metals are selected from one or more of the following: Cr, Mo or Ti; preferably, the other metals in the nickel-based metal are Cr or Mo; preferably, the metal composition in the nickel-based metal is, by mass fraction: Ni: 90-98%; Cr: 0-5%; Mo: 0-5%; Ti: 0-5%. Wherein, the loading amount of the nickel-based metal is the mass of the nickel-based metal / the total mass of (nickel-based metal+Al2O3).

[0033] In order to further convert all the products into 1,4-butanediamine in the second hydrogenation reaction and reduce the occurrence of side reactions, in a preferred embodiment, the precious metal of the second catalyst includes: Pt or Pd; preferably, the precious metal content in the second catalyst is 0.5-1% by mass, and the rest is C.

[0034] In order to further efficiently obtain 1,4-butanediamine with high selectivity and high yield, in a preferred embodiment, the concentration of succinonitrile in the succinonitrile solution is 10-50%, preferably 15-25%, by mass fraction.

[0035] Any solvent that can dissolve succinonitrile is suitable for the present application. To better complete the hydrogenation reaction of the present application, in a preferred embodiment, the solvent of the succinonitrile solution is selected from one or more of the following: methanol, ethanol or water; preferably, the solvent of the succinonitrile solution is methanol.

[0036] In order to further completely convert the reactants and reduce the occurrence of side reactions, it is necessary to select appropriate amounts of reactants and catalysts. In a preferred embodiment, the amount of the first catalyst is 0.1-5 times the mass of succinonitrile in the succinonitrile solution, preferably 0.5-1 times.

[0037] To further efficiently complete the first hydrogenation reaction, in a preferred embodiment, the temperature of the first hydrogenation reaction is 80-150°C, preferably 90-110°C; preferably, the time of the first hydrogenation reaction is 1-5h, preferably 2-3h; preferably, the pressure of the first hydrogenation reaction is 0.5-2.5MPa, preferably 1-1.5MPa.

[0038] In order to further completely convert the reactants and reduce the occurrence of side reactions, it is necessary to select appropriate amounts of reactants and catalysts. In a preferred embodiment, the amount of the second catalyst is 0.01-0.3 times the mass of succinonitrile in the succinonitrile solution, preferably 0.05-0.1 times.

[0039] To further efficiently complete the second hydrogenation reaction, in a preferred embodiment, the temperature of the second hydrogenation reaction is 70-120°C, preferably 80-90°C; preferably, the time of the second hydrogenation reaction is 0.1-3h, preferably 0.5-1h; preferably, the pressure of the second hydrogenation reaction is 0.5-1.5MPa, preferably 0.7-1.0MPa.

[0040] In order to efficiently prepare the 1,4-butanediamine of the present application in industrial production, in a preferred embodiment, the reactants for the first hydrogenation reaction are fed from the upper end of the first reactor, and the first hydrogenation reaction product is discharged from the lower end of the first reactor; the first hydrogenation reaction product is fed from the upper end of the second reactor, and the second hydrogenation reaction product is discharged from the lower end of the second reactor. The catalyst is loaded in the reactor, so that the reactants and the catalyst can be fully contacted, and a relatively complete and highly selective hydrogenation reaction is carried out to obtain 1,4-butanediamine with a high yield and purity.

[0041] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0042] Example 1

[0043] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 20% by mass fraction, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of the first catalyst is 1 times the weight of succinonitrile. A methanol solution of succinonitrile and hydrogen are simultaneously introduced into a fixed bed reactor filled with the first catalyst to perform a first hydrogenation reaction. Among them, the concentration of the methanol solution of succinonitrile is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0044] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 98.32%, diaminobutane was 1.65%, tetrahydropyrrole was 0.02%, and tetramethylenetriamine was 0.01%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.97%.

[0045] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0MPa, and the reaction time is 1h.

[0046] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.03%, the content of diaminobutyrate was 99.89%, the content of tetrahydropyrrole was 0.05%, and the content of tetramethylenetriamine was 0.03%; the conversion rate of aminobutyronitrile was 99.97%, the selectivity of the reaction was 99.92%, and the yield of diaminobutyrate was 99.89%.

[0047] Example 2

[0048] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 20% by mass fraction, and the nickel-based catalyst composition is: Ni 95%, Mo 5%. The amount of the first catalyst is 1 times the weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to carry out the first hydrogenation reaction. Wherein, the concentration of succinonitrile methanol solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0049] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 98.13%, diaminobutane was 1.82%, tetrahydropyrrole was 0.03%, and tetramethylenetriamine was 0.02%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.95%.

[0050] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0MPa, and the reaction time is 1h.

[0051] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.01%, the content of diaminobutyrate was 99.92%, the content of tetrahydropyrrole was 0.04%, and the content of tetramethylenetriamine was 0.03%; the conversion rate of aminobutyronitrile was 99.99%, the selectivity of the reaction was 99.93%, and the yield of diaminobutyrate was 99.92%.

[0052] Example 3

[0053] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 20% by mass fraction, and the nickel-based catalyst composition is: Ni 95%, Ti 5%. The amount of the first catalyst is 1 times the weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to carry out the first hydrogenation reaction. Wherein, the concentration of succinonitrile methanol solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0054] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 97.14%, diaminobutane was 2.48%, tetrahydropyrrole was 0.25%, and tetramethylenetriamine was 0.13%; the conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.62%.

[0055] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0MPa, and the reaction time is 1h.

[0056] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.04%, the content of diaminobutyrate was 99.03%, the content of tetrahydropyrrole was 0.65%, and the content of tetramethylenetriamine was 0.28%; the conversion rate of aminobutyronitrile was 99.96%, the selectivity of the reaction was 99.07%, and the yield of diaminobutyrate was 99.03%.

[0057] Example 4

[0058] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 20% by mass fraction, and the nickel-based catalyst composition is: Ni 94%, Cr 2%, Mo 2%, Ti 2%. The amount of the first catalyst is 1 times the weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to carry out the first hydrogenation reaction. Among them, the concentration of succinonitrile methanol solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0059] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 97.82%, diaminobutane was 2.04%, tetrahydropyrrole was 0.09%, and tetramethylenetriamine was 0.05%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.86%.

[0060] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0MPa, and the reaction time is 1h.

[0061] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.03%, the content of diaminobutyrate was 99.42%, the content of tetrahydropyrrole was 0.34%, and the content of tetramethylenetriamine was 0.21%; the conversion rate of aminobutyronitrile was 99.97%, the selectivity of the reaction was 99.45%, and the yield of diaminobutyrate was 99.42%.

[0062] Example 5

[0063] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 30% by mass fraction, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of the first catalyst is twice the weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to perform the first hydrogenation reaction. Wherein, the concentration of succinonitrile methanol solution is 25% by mass fraction, the reaction temperature is 130°C, the reaction pressure is 2.0MPa, and the reaction time is 1.5h.

[0064] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 97.49%, diaminobutane was 1.72%, tetrahydropyrrole was 0.56%, and tetramethylenetriamine was 0.23%; the conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.21%.

[0065] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 1%, and the amount of the second catalyst is 0.2 times the initial weight of succinonitrile. The reaction temperature is 80°C, the pressure is 0.8MPa, and the reaction time is 2h.

[0066] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.02%, the content of diaminobutyrate was 98.75%, the content of tetrahydropyrrole was 0.81%, and the content of tetramethylenetriamine was 0.42%; the conversion rate of aminobutyronitrile was 99.98%, the selectivity of the reaction was 98.77%, and the yield of diaminobutyrate was 98.75%.

[0067] Example 6

[0068] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 10% by mass, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of the first catalyst is 5 times the weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to carry out the first hydrogenation reaction. Among them, by mass fraction, the concentration of succinonitrile methanol solution is 50%, the reaction temperature is 150°C, the reaction pressure is 2.5MPa, and the reaction time is 1h.

[0069] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 95.32%, diaminobutane was 3.25%, tetrahydropyrrole was 0.95%, and tetramethylenetriamine was 0.48%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 98.57%.

[0070] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pd / C catalyst with a Pd content of 0.7%, and the amount of the second catalyst is 0.3 times the initial weight of succinonitrile. The reaction temperature is 70°C, the pressure is 0.5MPa, and the reaction time is 3h.

[0071] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.03%, the content of diaminobutyrate was 97.63%, the content of tetrahydropyrrole was 1.58%, and the content of tetramethylenetriamine was 0.76%; the conversion rate of aminobutyronitrile was 99.97%, the selectivity of the reaction was 97.66%, and the yield of diaminobutyrate was 97.63%.

[0072] Example 7

[0073] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 30% by mass fraction, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of the first catalyst is 3 times the weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to carry out the first hydrogenation reaction. Wherein, the concentration of succinonitrile methanol solution is 10% by mass fraction, the reaction temperature is 80°C, the reaction pressure is 0.5MPa, and the reaction time is 5h.

[0074] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 95.97%, diaminobutane was 3.32%, tetrahydropyrrole was 0.44%, and tetramethylenetriamine was 0.27%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.29%.

[0075] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 1%, and the amount of the second catalyst is 0.01 times the initial weight of succinonitrile. The reaction temperature is 120°C, the pressure is 1.5MPa, and the reaction time is 0.1h.

[0076] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.08%, the content of diaminobutyrate was 99.11%, the content of tetrahydropyrrole was 0.71%, and the content of tetramethylenetriamine was 0.38%; the conversion rate of aminobutyronitrile was 99.92%, the selectivity of the reaction was 98.91%, and the yield of diaminobutyrate was 98.83%.

[0077] Example 8

[0078] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 20% by mass fraction, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of the first catalyst is 1 times the weight of succinonitrile. Succinonitrile ethanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to perform the first hydrogenation reaction. Wherein, the concentration of the succinonitrile ethanol solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0079] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 97.59%, diaminobutane was 2.03%, tetrahydropyrrole was 0.23%, and tetramethylenetriamine was 0.15%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.62%.

[0080] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0 MPa, and the reaction time is 1 hour.

[0081] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.03%, the content of diaminobutyrate was 99.15%, the content of tetrahydropyrrole was 0.47%, and the content of tetramethylenetriamine was 0.35%; the conversion rate of aminobutyronitrile was 99.97%, the selectivity of the reaction was 99.18%, and the yield of diaminobutyrate was 99.15%.

[0082] Example 9

[0083] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 20% by mass fraction, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of the first catalyst is 1 times the weight of succinonitrile. Succinonitrile aqueous solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to carry out the first hydrogenation reaction. Among them, the concentration of the succinonitrile aqueous solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0084] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 96.78%, diaminobutane was 2.38%, tetrahydropyrrole was 0.56%, and tetramethylenetriamine was 0.28%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.16%.

[0085] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0 MPa, and the reaction time is 1 hour.

[0086] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.05%, the content of diaminobutyrate was 98.87%, the content of tetrahydropyrrole was 0.73%, and the content of tetramethylenetriamine was 0.35%; the conversion rate of aminobutyronitrile was 99.95%, the selectivity of the reaction was 98.92%, and the yield of diaminobutyrate was 98.87%.

[0087] Example 10

[0088] Step 1: The first catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 20% by mass fraction, and the nickel-based catalyst composition is: Ni 100%. The amount of the first catalyst is 1 times the weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the first catalyst to perform the first hydrogenation reaction. Wherein, the concentration of succinonitrile methanol solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0089] The reaction liquid obtained by the first hydrogenation reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 95.76%, diaminobutane was 3.15%, tetrahydropyrrole was 0.78%, and tetramethylenetriamine was 0.31%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 98.91%.

[0090] Step 2: The reaction liquid obtained from the first hydrogenation reaction is continuously fed to the upper part of the fixed bed reactor filled with the second catalyst, and hydrogen is introduced simultaneously to carry out the second hydrogenation reaction. The second catalyst is a Pt / C catalyst with a Pt content of 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0MPa, and the reaction time is 1h.

[0091] The reaction liquid obtained by the second hydrogenation reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 0.05%, the content of diaminobutyrate was 98.01%, the content of tetrahydropyrrole was 1.31%, and the content of tetramethylenetriamine was 0.63%; the conversion rate of aminobutyronitrile was 99.95%, the selectivity of the reaction was 98.06%, and the yield of diaminobutyrate was 98.01%.

[0092] Comparative Example 1

[0093] Step 1: The catalyst is a nickel-based catalyst loaded into Al2O3. The loading amount of the nickel-based metal in the first catalyst is 20% by mass fraction, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of the first catalyst is 1 times the weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into the fixed bed reactor filled with the catalyst. Among them, the concentration of succinonitrile methanol solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0094] The reaction liquid obtained by the above reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 98.32%, diaminobutane was 1.65%, tetrahydropyrrole was 0.02%, and tetramethylenetriamine was 0.01%. The conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.97%.

[0095] Step 2: The reaction liquid obtained by the above reaction is continuously fed into the upper part of the fixed bed reactor filled with catalyst, and hydrogen is introduced simultaneously. The catalyst is a nickel-based catalyst loaded into Al2O3, the loading amount of the nickel-based metal in the first catalyst is 20%, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of catalyst used is 1 times the weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0MPa, and the reaction time is 1h.

[0096] The reaction liquid obtained by the above reaction was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 15.81%, the content of diaminobutyrate was 79.01%, the content of tetrahydropyrrole was 3.31%, and the content of tetramethylenetriamine was 1.87%; the conversion rate of aminobutyronitrile was 84.19%, the selectivity of the reaction was 94.82%, and the yield of diaminobutyrate was 79.01%.

[0097] Comparative Example 2

[0098] Step 1: The catalyst is a Pt / C catalyst, the Pt content is 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into a fixed bed reactor filled with the catalyst. The concentration of the succinonitrile methanol solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0099] The reaction liquid obtained by the above reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 80.63%, diaminobutane was 18.72%, tetrahydropyrrole was 0.38%, and tetramethylenetriamine was 0.27%; the conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.35%.

[0100] Step 2: The reaction liquid obtained by the above reaction is continuously fed to the upper part of the fixed bed reactor filled with catalyst, and hydrogen is introduced simultaneously. The catalyst is a Pt / C catalyst, the Pt content is 0.5%, and the catalyst dosage is 0.1 times the initial weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0 MPa, and the reaction time is 1 hour.

[0101] The reaction liquid obtained by the above reaction was analyzed by gas chromatography, wherein aminobutyronitrile was not detected, the content of diaminobutyrate was 90.87%, tetrahydropyrrole was 5.82%, and tetramethylenetriamine was 3.31%; the conversion rate of aminobutyronitrile was 100%, the selectivity of the reaction was 90.87%, and the yield of diaminobutyrate was 90.87%.

[0102] Comparative Example 3

[0103] Step 1: The catalyst is a Pt / C catalyst, the Pt content is 0.5%, and the amount of the second catalyst is 0.1 times the initial weight of succinonitrile. Succinonitrile methanol solution and hydrogen are simultaneously introduced into a fixed bed reactor filled with the catalyst. The concentration of the succinonitrile methanol solution is 20% by mass fraction, the reaction temperature is 110°C, the reaction pressure is 1.5MPa, and the reaction time is 2h.

[0104] The reaction liquid obtained by the above reaction was analyzed by gas chromatography, wherein aminobutyronitrile was 80.63%, diaminobutane was 18.72%, tetrahydropyrrole was 0.38%, and tetramethylenetriamine was 0.27%; the conversion rate of diaminobutane was 100%, and the selectivity of the reaction was 99.35%.

[0105] Step 2: The reaction liquid obtained by the above reaction is continuously fed to the upper part of the fixed bed reactor filled with the catalyst, and hydrogen is introduced simultaneously. The catalyst is a nickel-based catalyst loaded into Al2O3, the loading amount of the nickel-based metal in the first catalyst is 20%, and the nickel-based catalyst composition is: Ni 95%, Cr 5%. The amount of catalyst used is 1 times the weight of succinonitrile. The reaction temperature is 90°C, the pressure is 1.0MPa, and the reaction time is 1h.

[0106] The reaction liquid of step 2 was analyzed by gas chromatography, wherein the content of aminobutyronitrile was 2.35%, the content of diaminobutyrate was 93.15%, the content of tetrahydropyrrole was 2.84%, and the content of tetramethylenetriamine was 1.66%; the conversion rate of aminobutyronitrile was 97.65%, the selectivity of the reaction was 95.50%, and the yield of diaminobutyrate was 93.25%.

[0107] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: adopting a step-by-step hydrogenation method, using a corresponding catalyst, the depth of hydrogenation is controllable, the first step mainly generates aminobutyronitrile, and the second step further hydrogenates to prepare 1,4-butanediamine, which can effectively reduce side reactions, produce fewer by-products, and have high reaction selectivity (the selectivity of the first hydrogenation reaction is ≥98.57%; the selectivity of the second hydrogenation reaction is ≥97.63%). The separation difficulty is low during post-processing, and the product purity is high. In addition, this method does not need to add other components such as ammonia to inhibit side reactions, and the industrial process flow is simple and easy to promote and use.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing 1,4-butanediamine, characterized in that: The preparation method comprises: The succinonitrile solution and hydrogen undergo a first hydrogenation reaction under the catalysis of a first catalyst to obtain a first hydrogenation reaction product; The first hydrogenation reaction product and the hydrogen are subjected to a second hydrogenation reaction under the catalysis of a second catalyst to obtain the 1,4-butanediamine; Wherein, the first catalyst is a nickel-based catalyst supported on Al2O3, and the second catalyst is a precious metal catalyst supported on C.

2. The preparation method according to claim 1, characterized in that: In terms of mass fraction, the loading amount of the nickel-based metal in the first catalyst is 10-30%, preferably 20-30%; Preferably, the nickel-based metal further comprises other metals besides nickel, wherein the other metals are selected from one or more of the following: Cr, Mo or Ti; Preferably, the other metal in the nickel-based metal is Cr or Mo; Preferably, the metal composition of the nickel-based metal is, by mass fraction, Ni: 90-98%; Cr: 0-5%; Mo: 0-5%; Ti: 0-5%.

3. The preparation method according to claim 1, characterized in that: The noble metal in the second catalyst includes: Pt or Pd; Preferably, the precious metal content in the second catalyst is 0.5-1% by mass.

4. The preparation method according to claim 1, characterized in that: In terms of mass fraction, the concentration of succinonitrile in the succinonitrile solution is 10-50%, preferably 15-25%.

5. The preparation method according to claim 1, characterized in that: The solvent of the succinonitrile solution is selected from one or more of the following: methanol, ethanol or water; Preferably, the solvent of the succinonitrile solution is methanol.

6. The preparation method according to claim 1, characterized in that: The usage of the first catalyst is 0.1-5 times, preferably 0.5-1 times, the mass of succinonitrile in the succinonitrile solution.

7. The preparation method according to claim 1, characterized in that: The temperature of the first hydrogenation reaction is 80-150°C, preferably 90-110°C; Preferably, the first hydrogenation reaction time is 1-5h, preferably 2-3h; Preferably, the pressure of the first hydrogenation reaction is 0.5-2.5 MPa, preferably 1-1.5 MPa.

8. The preparation method according to claim 1, characterized in that: The amount of the second catalyst used is 0.01-0.3 times the mass of succinonitrile in the succinonitrile solution, preferably 0.05-0.1 times.

9. The preparation method according to claim 1, characterized in that: The temperature of the second hydrogenation reaction is 70-120°C, preferably 80-90°C; Preferably, the second hydrogenation reaction time is 0.1-3h, preferably 0.5-1h; Preferably, the pressure of the second hydrogenation reaction is 0.5-1.5 MPa, preferably 0.7-1.0 MPa.

10. The preparation method according to claim 1, characterized in that: The reactants for the first hydrogenation reaction are fed from the upper end of the first reactor, and the first hydrogenation reaction product is discharged from the lower end of the first reactor; The first hydrogenation reaction product is fed from the upper end of the second reactor, and the second hydrogenation reaction product is discharged from the lower end of the second reactor.

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