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CN-121974823-A - Method for efficiently synthesizing 6-aminocapronitrile based on continuous flow microreactor

CN121974823ACN 121974823 ACN121974823 ACN 121974823ACN-121974823-A

Abstract

The invention provides a method for efficiently synthesizing 6-aminocapronitrile based on a continuous flow microreactor, which comprises the following steps of firstly stirring a caprolactam solution of reactants and a solid catalyst uniformly to obtain a solid-liquid mixed reactant, then respectively preheating the solid-liquid mixture and ammonia gas, continuously injecting the mixture into a mixer to fully mix gas-liquid two-phase reactants to obtain a fully mixed reaction solution after reaching a reaction temperature, continuously inputting the reactant solution into the microreactor, carrying out heterogeneous catalytic ammonification reaction for 0.5-10 min under the conditions that the reaction temperature is 60-300 ℃ and the pressure is 0.01-3 MPa, and finally carrying out heat exchange cooling and gas-solid-liquid separation treatment on the product to obtain the 6-aminocapronitrile. The invention strengthens mass transfer through the microreactor, so that the conversion rate is up to 99.7%, the yield is 98.2%, the reaction time is shortened to 0.5-10 min, and the problems of more side reactions and low efficiency in the traditional process are solved.

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 (6)

  1. 1. A method for efficiently synthesizing 6-aminocapronitrile based on a continuous flow microreactor is characterized by comprising the following steps of: (1) Firstly, uniformly stirring a caprolactam solution of reactants and a solid catalyst to obtain a solid-liquid mixed reactant, then respectively preheating the solid-liquid mixture and ammonia gas, and continuously injecting the mixture into a mixer to fully mix the gas-liquid two-phase reactant after the reaction temperature is reached to obtain a fully mixed reaction solution; (2) Continuously inputting the completely mixed reactant solution obtained in the step (1) into a microreactor, and carrying out heterogeneous catalytic ammonification reaction for 0.5-10 min under the conditions that the reaction temperature is 60-300 ℃ and the pressure is 0.01-3 MPa; (3) Carrying out heat exchange cooling and gas-solid-liquid separation treatment on the product output from the microreactor in the step (2) to obtain a product 6-aminocapronitrile; Wherein the solid catalyst in the step (1) is at least one of a silicon-aluminum molecular sieve, a transition metal oxide, a magnesium oxide/carbon load, a magnesium phosphate/silicon dioxide and a calcium phosphate/aluminum oxide load.
  2. 2. The method for efficiently synthesizing 6-aminocapronitrile based on the continuous flow microreactor according to claim 1, wherein the volume flow ratio of caprolactam solution to ammonia gas in the reactant in the step (1) is 1:1-100, the mass fraction of caprolactam in the caprolactam solution is 1-30 wt%, and the mass fraction ratio of caprolactam to solid catalyst is 1-30:1.
  3. 3. The method for efficiently synthesizing 6-aminocapronitrile based on the continuous flow microreactor according to claim 1, wherein the ammonia gas flow rate in the step (1) is 5-100 ml/min.
  4. 4. The method for efficiently synthesizing 6-aminocapronitrile based on the continuous flow microreactor according to claim 1, wherein the preheating pipe used in the preheating in the step (1) has an inner diameter of 0.1-6mm and a length of 0.1-3 m.
  5. 5. The method for efficiently synthesizing 6-aminocapronitrile based on the continuous flow microreactor according to claim 4, wherein the inner diameter of the preheating pipe is any one of polytetrafluoroethylene, stainless steel pipe, hastelloy and the like.
  6. 6. The method for efficiently synthesizing 6-aminocapronitrile based on the continuous flow microreactor according to claim 1, wherein the microreactor is any one of a static microreactor, a rotary microreactor and an ultrasonic microreactor.

Description

Method for efficiently synthesizing 6-aminocapronitrile based on continuous flow microreactor Technical Field The invention relates to the technical field of chemical reaction engineering, in particular to a method for efficiently synthesizing 6-aminocapronitrile based on a continuous flow microreactor. Background 1, 6-Hexamethylenediamine (HMDA) is an important raw material for polymerizing monomers, and is commonly used for synthesizing nylon polymeric materials including nylon 610,66 and 612 and other products. According to market data statistics, 2024 global nylon market scale is up to 326.4 hundred million dollars, and is a widely used polymeric material with an annual growth rate of 5.1%. At present, a common method for synthesizing 1, 6-hexamethylenediamine comprises the steps of ammonifying and dehydrating a caprolactam reactant to obtain an intermediate product 6-aminocapronitrile, and synthesizing the intermediate product through a catalytic hydrogenation reaction. Wherein, caprolactam and ammonia are used as reactants to synthesize a key intermediate 6-aminocapronitrile, which relates to a common multiphase reaction process. At present, the reaction is usually carried out in a stirred tank reactor, and the problems of low service life of the catalyst, polymer blockage and the like caused by long reaction time, low product selectivity, easy occurrence of polymerization side reaction and the like exist due to low gas-liquid-solid multiphase mass transfer and heat transfer efficiency in the reactor. Therefore, developing a process for the efficient synthesis of 6-aminocapronitrile based on a continuous flow microreactor is very important for improving the yield and economy of the intermediate 6-aminocapronitrile. Disclosure of Invention The invention aims to solve the technical problem of providing a method for efficiently synthesizing 6-aminocapronitrile based on a continuous flow microreactor, which strengthens a multiphase mass transfer-reaction process through the microreactor, improves the speed and selectivity of the reaction process, and avoids polymerization side reaction, thereby solving the problems of short service life of a catalyst and low selectivity of a product. The invention is realized in the following way: A method for efficiently synthesizing 6-aminocapronitrile based on a continuous flow microreactor comprises the following steps: (1) Firstly, uniformly stirring a caprolactam solution of reactants and a solid catalyst to obtain a solid-liquid mixed reactant, then respectively preheating the solid-liquid mixture and ammonia gas, and continuously injecting the mixture into a mixer to fully mix the gas-liquid two-phase reactant after the reaction temperature is reached to obtain a fully mixed reaction solution; (2) Continuously inputting the completely mixed reactant solution obtained in the step (1) into a microreactor, and carrying out heterogeneous catalytic ammonification reaction for 0.5-10 min under the conditions that the reaction temperature is 60-300 ℃ and the pressure is 0.01-3 MPa; (3) Carrying out heat exchange cooling and gas-solid-liquid separation treatment on the product output from the microreactor in the step (2) to obtain a product 6-aminocapronitrile; Wherein the solid catalyst in the step (1) is at least one of a silicon-aluminum molecular sieve, a transition metal oxide, a magnesium oxide/carbon load, a magnesium phosphate/silicon dioxide and a calcium phosphate/aluminum oxide load. Further, the volume flow ratio of the caprolactam solution to the ammonia gas in the reactant in the step (1) is 1:1-100, the mass fraction of the caprolactam in the caprolactam solution is 1-30wt%, and the mass fraction ratio of the caprolactam to the solid catalyst is 1-30:1. Further, the ammonia flow in the step (1) is 5-100 ml/min. Further, the preheating tube adopted in the step (1) has an inner diameter of 0.1-6mm and a length of 0.1-3 m. Further, the inner diameter of the preheating pipe is made of any one of polytetrafluoroethylene, stainless steel pipe, hastelloy and the like. Further, the microreactor is any one of a static microreactor, a rotary microreactor and an ultrasonic microreactor. The invention has the following advantages: The invention can raise the conversion rate of caprolactam reactant to 99.7%, the yield of 6-aminocapronitrile product to 98.2%, and the reaction time is shortened to the minute level (0.5-10 min) to avoid polymerization side reaction. Detailed Description The technical scheme of the present invention will be clearly and completely described in connection with the following detailed description. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufac