Method for preparing hexamethylenediamine key intermediate 6-aminocapronitrile by two-step method

A technology of aminocapronitrile and hexamethylenediamine, which is applied in the preparation of carboxylic acid amides, the preparation of cyanide reaction, chemical instruments and methods, etc., can solve the problems of easy coking of catalysts, and achieve the avoidance of coking of catalysts, lasting conversion rate, and prolonged use. effect of life

Active Publication Date: 2020-09-15
JIANGSU YANGNONG CHEM GROUP +2
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0007] The main purpose of the present invention is to provide a method for preparing hexamethylenediamine key intermediate 6-aminocapronitrile by a two-step method, so as to solve the problem that the catalyst for forming 6-aminocapronitrile by one-step method in the prior art is easy to coke

Method used

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  • Method for preparing hexamethylenediamine key intermediate 6-aminocapronitrile by two-step method
  • Method for preparing hexamethylenediamine key intermediate 6-aminocapronitrile by two-step method

Examples

Experimental program
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Effect test

Embodiment 1

[0036] Mix caprolactam and hydrogen chloride aqueous solution in a reaction kettle. The mass ratio of caprolactam: water: hydrogen chloride is 1:6:0.001. The mixture is reacted at 150°C and 0.5MPa for 48 hours. The obtained material is flashed to remove 80% of the water, and then the reaction Ammonia gas at 150° C. was passed into the kettle at a flow rate of 3 times the weight of caprolactam per hour for 5 hours to obtain crude aminocaproamide.

[0037] Aminocaproamide crude product was mass space velocity 8h -1 Pump into the reactor that alumina catalyst is housed from the top, pass into the ammonia gas of 300 ℃ with the flow rate of 7 times amino caproamide crude product weight, ammonia gas enters simultaneously from the reactor bottom and the middle part (bottom and middle part ammonia gas pumping ratio 2:1), the conversion rate of total caprolactam per pass is 99.5%, the highest selectivity of aminocapronitrile is 99.3%, and the single pass life of the catalyst is judged ...

Embodiment 2

[0039] Mix caprolactam and hydrogen chloride aqueous solution in a reaction kettle, the mass ratio of caprolactam:water:sodium hydroxide is 1:6:0.3, the mixture is reacted at 280°C and 7.5MPa for 12h, and the obtained material is flashed to remove 80% of the water, and then Ammonia gas at 200° C. was passed into the reactor at a flow rate of 1 times the weight of caprolactam per hour for 3 hours to obtain crude aminocaproamide.

[0040] Aminocaproamide crude product was mass space velocity 0.5h -1 Pump into the reactor that alumina catalyst is housed from the top, pass into the ammonia gas of 200 ℃ with the flow rate of 0.5 times amino caproamide crude product weight, ammonia gas enters simultaneously from the reactor bottom and middle part (bottom and middle part ammonia gas pumping ratio is 1:1), the conversion rate of total caprolactam per pass is 99.3%, the highest selectivity of aminocapronitrile is 98.7%, and the one-pass life of the catalyst is 1350h when the selectivit...

Embodiment 3

[0042] Mix caprolactam and hydrogen chloride aqueous solution in a reaction kettle. The mass ratio of caprolactam: water: hydrogen chloride is 1:3:0.01. The mixture is reacted at 200°C and 1.7MPa for 3 hours. Ammonia gas at 250° C. was passed into the kettle at a flow rate of 0.5 times the weight of caprolactam per hour for 2 hours to obtain crude aminocaproamide.

[0043] Aminocaproamide crude product was mass space velocity 1h -1 Pump into the reactor that alumina catalyst is housed from the top, pass into the ammonia gas of 230 ℃ with the flow rate of 4 times amino caproamide crude product weight, ammonia gas enters simultaneously from the reactor bottom and the middle part (bottom and middle part ammonia gas pumping ratio 1:1), the conversion rate of total caprolactam per pass is 99.8%, the highest selectivity of aminocapronitrile is 99.4%, and the single pass life of the catalyst is 1550h when the selectivity of aminocapronitrile is less than 98%.

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Abstract

The invention provides a method for preparing a hexamethylenediamine key intermediate 6-aminocapronitrile by a two-step method. The method comprises the following steps: step S1, in a first reactor, after caprolactam is subjected to a hydrolysis reaction in an aqueous solution, introducing first hot ammonia gas into the first reactor to obtain an aminocaproamide crude product, the temperature of the first hot ammonia gas being 150-250 DEG C; S2, performing catalytic dehydration on the aminocaproamide crude product and second hot ammonia gas in a second reactor to obtain aminocapronitrile, wherein the temperature of the second hot ammonia gas ranges from 200 DEG C to 300 DEG C. According to the invention, the polymerization of the hydrolysate is effectively controlled in the step S1 so thatpolymerization of the polymer on the surface of the catalyst when the aminocaproamide crude product participates in the catalytic dehydration reaction in the step S2 is effectively relieved, coking of the catalyst is avoided, the service life of the catalyst is prolonged, and then lasting high-conversion-rate and high-selectivity preparation of 6-aminocapronitrile from caprolactam is guaranteed.

Description

technical field [0001] The invention relates to the technical field of synthesis of hexamethylenediamine, in particular to a two-step method for preparing the key intermediate of hexamethylenediamine, 6-aminocapronitrile. Background technique [0002] 1,6-Hexamethylenediamine is an important high-performance material intermediate, mainly used in the production of polyamide, such as nylon 66, nylon 610, etc. It can also be used in the production of polyurethane, and can also be used as a curing agent for urea-formaldehyde resin and epoxy resin . [0003] According to different raw materials, the production method of hexamethylenediamine is divided into adiponitrile method and caprolactam method, the former is the main industrial production method, and the production method of adiponitrile can be divided into: butadiene method, acrylonitrile method, adiponitrile method, Diacid method. [0004] The butadiene method is in the presence of transition metals such as nickel and ph...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C253/20C07C255/24
CPCC07C253/20C07C231/02C07C227/22C07C255/24C07C237/06C07C229/08
Inventor 王根林徐林丁克鸿梅学赓王铖殷恒志刘鑫王鑫宇郭博博
Owner JIANGSU YANGNONG CHEM GROUP
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