CN-121974807-A - Method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on continuous flow fixed bed reactor

Abstract

The invention discloses a method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on a continuous flow fixed bed reactor, which comprises the steps of premixing a 6-aminocapronitrile solution with hydrogen, continuously inputting a mixed reactant stream into the fixed bed reactor filled with a catalyst, staying for 0.5-5 min under the conditions of 50-150 ℃ and 0.5-3.5MPa of reaction temperature, carrying out multiphase hydrogenation reaction, and carrying out on-line separation on a product to obtain high-purity 1, 6-hexamethylenediamine. The method shortens the reaction time to within 5 minutes by strengthening gas-liquid-solid mass transfer, improves the conversion rate of the reactants to 93-100 percent, improves the yield of the 1, 6-hexamethylenediamine to above 92 percent, and obviously improves the production efficiency and the yield of the reactants.

Inventors

• ZHOU CAIJIN
• GE XUEHUI
• LIU YAO
• LIN YUJING
• WANG XIAODA
• JIANG LILONG
• PAN DEBIAO
• WANG JIANHUA

Assignees

• 福建省恒申化工科技有限公司
• 福州大学

Dates

Publication Date

20260505

Application Date

20251215

Claims (4)

1. 1. A method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on a continuous flow fixed bed reactor, which is characterized by comprising the following steps: (a) Firstly, preheating reactants to be hydrogenated to reach a reaction temperature, and fully mixing the reactants with a hydrogen flow through a mixer to obtain a mixed reactant flow which is completely mixed; (b) Continuously inputting the mixed reactant flow obtained in the step (a) into a fixed bed reactor filled with a catalyst, and carrying out multiphase hydrogenation reaction at the reaction temperature of 50-150 ℃ and the pressure of 0.5-3.5 MPa for 0.5-5 min; (c) Carrying out online rapid gas-liquid separation on the product obtained in the step (b) to obtain a 1, 6-hexamethylenediamine product solution; The reactant in the step (a) is 6-aminocapronitrile solution, and the mixer is any one of a micromixer, a static mixer, a rotator mixer and an ultrasonic mixer; the fixed bed reactor filled with the catalyst in the step (b), wherein the filled catalyst is any one of nickel/aluminum oxide, cobalt/carbon, ruthenium/carbon and palladium/silicon oxide.
2. 2. The method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on a continuous flow fixed bed reactor according to claim 1, wherein the solute to solvent ratio of the reactant solution to be hydrogenated in the step (a) is mixed according to a mass ratio of 1:2-1:30.
3. 3. The method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on a continuous flow fixed bed reactor according to claim 1, wherein the reactants in the step (a) and hydrogen are mixed according to a volume flow ratio of 1:200-1.
4. 4. The method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on a continuous flow fixed bed reactor according to claim 1, wherein the synthesis device structure of the method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation is as follows, and comprises a mixer, a fixed bed reactor of a reaction part filled with a catalyst, and an online gas-liquid separator, wherein the mixer is arranged at the inlet of the fixed bed reactor, and the online gas-liquid separator is arranged at the outlet of the fixed bed reactor.

Description

Method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on continuous flow fixed bed reactor Technical Field The invention relates to the technical field of organic amine compound synthesis, in particular to a method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on a continuous flow fixed bed reactor. Background 1, 6-Hexamethylenediamine (HMDA) is used as an important chemical raw material and is generally used in the synthesis process of nylon materials, diisocyanate, urea-formaldehyde resins and other materials. For example, HMDA can be polymerized with adipic acid and sebacic acid to form nylon 610, respectively, and then processed into various high performance nylon products and used in various fields such as electrical, aerospace, and automotive. Currently, the production methods of 1, 6-hexamethylenediamine include a1, 4-butadiene hydrocyanation method, a caprolactam ammonification and dehydration method, a1, 6-adipate ammonification method, a1, 6-hexanedialdehyde ammonification method and the like. The caprolactam ammonification and dehydration method has the advantages of few byproducts, high HMDA selectivity of the product and the like, and is an important production method for synthesizing 1, 6-hexamethylenediamine. The synthesis method takes caprolactam and ammonia as reactants, and under the action of a catalyst, hydrolysis, ammoniation and dehydration reaction are carried out to generate 6-Aminocapronitrile (ACN), and then the ACN is hydrogenated to generate the product 1, 6-hexamethylenediamine. Among them, ACN catalytic hydrogenation is an important process for synthesizing 1, 6-hexamethylenediamine products. The traditional hydrogenation reactors used in industry, such as a high-temperature high-pressure stirred tank reactor, a bubble column reactor, a trickle bed reactor and the like, have the problems of long reaction time, low product yield, high energy consumption and the like due to the problems of limited gas-liquid-solid multiphase mass transfer, low heat transfer efficiency and the like in the reactors, thereby increasing the production cost of products and reducing the production efficiency. Disclosure of Invention The invention aims to solve the technical problems of providing a method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on a continuous flow fixed bed reactor, which utilizes a continuous flow reactor process strengthening technology to realize the full mixing of reactants and catalysts and strengthen the mass transfer process of gas-liquid-solid three phases so as to improve the reaction speed and the product yield. The invention is realized in the following way: a method for synthesizing 1, 6-hexamethylenediamine by one-step high-efficiency hydrogenation based on a continuous flow fixed bed reactor, which is characterized by comprising the following steps: (a) Firstly, preheating reactants to be hydrogenated to reach a reaction temperature, and fully mixing the reactants with a hydrogen flow through a mixer to obtain a mixed reactant flow which is completely mixed; (b) Continuously inputting the mixed reactant flow obtained in the step (a) into a fixed bed reactor filled with a catalyst, and carrying out multiphase hydrogenation reaction at the reaction temperature of 50-150 ℃ and the pressure of 0.5-3.5 MPa for 0.5-5 min; (c) And (c) carrying out online rapid gas-liquid separation on the product obtained in the step (b) to obtain a 1, 6-hexamethylenediamine product solution. The reactant in the step (a) is 6-aminocapronitrile solution, and the mixer is any one of a micromixer, a static mixer, a rotator mixer and an ultrasonic mixer; the fixed bed reactor filled with the catalyst in the step (b), wherein the filled catalyst is any one of nickel/aluminum oxide, cobalt/carbon, ruthenium/carbon and palladium/silicon oxide. Further, the solute and solvent ratio of the reactant solution to be hydrogenated in the step (a) is mixed according to the mass ratio of 1:2-1:30. Further, the reactant in the step (a) and hydrogen are mixed according to the volume flow ratio of 1:200-1. Further, the one-step high-efficiency hydrogenation synthesis method of 1, 6-hexamethylenediamine is based on a synthesis device structure which comprises a mixer, a fixed bed reactor filled with a catalyst in a reaction part and an online gas-liquid separator, wherein the mixer is arranged at the inlet of the fixed bed reactor, and the online gas-liquid separator is arranged at the outlet of the fixed bed reactor. The invention has the following advantages: (1) The mass transfer efficiency is improved, so that the reaction time is shortened to be within 5 minutes (compared with the traditional process for several hours); (2) The conversion rate of the reactants is as high as 93-100%, and the HMDA yield is improved to 90-96%; (3) Continuous operation reduces energy consumpti