Method for preparing 1, 3-cyclohexanediamine by hydrogenation of m-xylylenediamine

Abstract

The invention relates to a method for preparing 1, 3-butanediol by hydrogenation of m-xylylenediamine. According to the method, hydrogenation of high-concentration m-xylylenediamine can be realized toprepare the high-cis-form-content 1, 3-cyclohexanediamine. The method comprises the following steps: adding a certain mass of m-xylylenediamine into a system containing a catalyst, a solvent, a reaction additive and high-pressure hydrogen at a constant speed so that the m-xylylenediamine is kept at a relatively low concentration in the whole reaction process through controlling the feeding rate of m-xylylenediamine. High-concentration hydrogenation mother liquor can be obtained while high-selectivity selectivity and yield of 1, 3-cyclohexylenediamine are realized. By adding a nitrogen-containing rigid cyclic compound into a reaction system, the content of cis-form bodies in a hydrogenation product 1, 3-cyclohexanediamine can be effectively increased, and a 1, 3-cyclohexanediamine productwith a cis-form body / trans-form body ratio of 80 / 20 or above is obtained. The method is easy to implement and has an industrial application prospect.

Description

technical field [0001] The invention relates to a method for preparing 1,3-cyclohexanedimethylamine by hydrogenating m-xylylenediamine, in particular to a method for preparing 1,3-cyclohexane with high cis-body content by hydrogenating m-xylylenediamine with high concentration The method for dimethylamine belongs to the field of synthesis of amine compounds. Background technique [0002] 1,3-Cyclohexanedimethylamine is an important fine chemical, which has a wide range of applications in the fields of epoxy curing agent, isocyanate and polyamide. [0003] The main preparation methods of 1,3-cyclohexanedimethylamine include hydrogenation of isophthalonitrile, hydroamination of 1,3-cyclohexanedimethanol and hydrogenation of m-xylylenediamine. Among them, the hydrogenation method of m-xylylenediamine has the advantages of high conversion rate of raw materials, high selectivity of products, and easy separation and purification of products. method. [0004] Patent US5741928 ad...

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Problems solved by technology

[0013] In order to overcome the low concentration of the existing m-xylylenediamine hydrogenation substrate, the present invention causes large amount of solvent, high energy consumption for product separation, and low production efficiency of reactor per unit volume Low, and need to increase the cis-isomer content in the 1,3-cyclohexanedimethylamine product through subsequent isomerization reaction, develop a high-concentration m-xylylenediamine hydrogenation to prepare high cis-isomer content1 , the method of 3-cyclohexanedimethylamine, its main features are: (1) by adding a certain quality m-xylylenediamine to the system containing catalyst, solvent, reaction additive and high-pressure hydrogen at a constant rate, by controlling the m-xylylenediamine The feeding rate of xylylenediamine keeps the concentration of m-xylylenediamine low throughout the reaction process, which can not only achieve high selectivity and yield of 1,3-cyclohexyldimethylamine, but also obtain high concentration (2) by adding pyridine, 2-picoline, 3-picoline, quinoline, 2-methylquinoline, 3-methylquinoline, isoquinoline, 6 One or more of nitrogen-containing rigid cyclic compounds such as methylisoquinoline, 2,2'-bipyridine, 4,4'-bipyridine, 1,10-phenanthroline as reaction additives, not only It can increase the content of the cis-isomer in the hydrogenation product 1,3-cyclohexanedimethylamine, and can also inhibit the side reaction of deamination, and improve the selectivity and yield of 1,3-cyclohexanedimethylamine