Method for synthesizing hexamethylenediamine and co-producing n-hexylamine and cyclohexylimide

Abstract

The invention relates to a method for synthesizing hexamethylenediamine and co-producing n-hexylamine and cyclohexylimide, which comprises the following steps: simultaneously conveying ammonia gas andcaprolactam into a first reactor, and carrying out ammoniation reaction under the action of a catalyst to obtain ammoniation liquid; and putting ammoniation liquid obtained by the ammoniation reaction into a second reactor, adding a catalyst and a solvent, and carrying out hydrogenation reaction to obtain products hexamethylenediamine, n-hexylamine and cyclohexyleneimine. According to the invention, the method for co-production of three products of hexamethylenediamine, n-hexylamine and cyclohexyleneimine by the same process is innovatively designed, the problems existing in independent production of each product in the prior art are effectively overcome, the process route is simple, the operation is simple, convenient and safe, continuous production can be realized, the product yield ishigh, and the economic benefit is greatly improved; besides, by regulating and controlling the reaction conditions of the process, the proportion of three products, namely hexamethylenediamine, n-hexylamine and cyclohexyleneimine, can be regulated and controlled, so that production is matched with actual market requirements, and the anti-risk capacity and profit capacity of the process are fully improved.

Description

technical field [0001] The invention relates to the technical field of organic chemical industry, in particular to a method for synthesizing hexamethylenediamine and coproducing n-hexylamine and cyclohexylimine. Background technique [0002] Hexamethylenediamine is a key raw material in the nylon industry. It is commonly used in the industry to synthesize nylon 66 and nylon 610, and then to make products such as nylon resin, nylon fiber and engineering plastics. At present, the large-scale industrialized production method of hexamethylenediamine is mainly produced by direct hydrogenation of adiponitrile under the action of a nickel-based catalyst. However, during the implementation of this process, it is generally accompanied by the production of hexamethylenediamine, which has a great impact on the quality of the synthetic nylon 66 product. Impurity diaminocyclohexane, and the impurity is extremely difficult to separate. In the prior art, patent CN107739318A discloses a me...

AI Technical Summary

Problems solved by technology

At present, the preparation methods of cyclohexyl imine mainly include two kinds: one is obtained by deamination and cyclization of 1,6-hexamethylenediamine. Since this process fails to completely solve the technical problem of intermolecular deamination, At present, this method has been basically eliminated; the other one uses aniline as a raw material, mixes aniline vapor and hydrogen into the reactor, and carries out hydrogenation reaction at 130°C to 170°C in the presence of a cobalt catalyst. The reaction is cooled and then distilled to obtain Finished product, but the process is complicated and the preparation cost is high

Patent CN1483725A in the prior art discloses a production method of cyclohexyl imine and its technology, using caprolactam as raw material and hydrogen at 180°C to 260°C, under the condition of catalyst and white oil, hydrogen and caprolactam undergo reduction The reaction produces cyclohexyl imine; the crude product obtained by this method exists in the form of gas and is combined with unreacted hydrogen to form a mixed gas, and then the mixed gas needs to be compressed, condensed, reboiled and other operations to obtain the product, and the separation of the product is difficult , long operation process and high operational safety risks