氯代苯胺液相催化加氢合成环己酮

Liquid phase catalytic hydrogenation of chloroaniline into cyclohexanone

提出了一种催化降解氯代苯胺高选择性合成环己酮的技术.在La修饰Pd/Al2O3催化剂作用下,通过催化加氢的方法实现了由多氯代苯胺(2,4,6-三氯苯胺和2,4,-二氯苯胺)高选择性地合成环己酮(不含环己醇).在优化的反应条件下,2,4,6-三氯苯胺加氢生成环己酮的转化率和选择性分别为100%和98.6%(没有检测到环己醇);2,4,-二氯苯胺加氢生成环己酮的转化率和选择性均为100%.氯代苯胺在Pd/La-Al2O3催化剂表面首先发生加氢脱氯/N-甲基化等反应生成苯胺、N-甲基苯胺和N,N-二甲基苯胺等中间产物,随后这些中间产物发生苯环加氢、氨基水解/醇解等反应得到环己酮;氯代苯胺上Cl元素的存在和体系中水的含量是影响环己酮选择性的重要因素.

A method for the degradation of chloraniline for high selective synthesis of cyclohexanone was proposed. The cyclohexanone was synthesized from multichloraniline（2,4,6-trichloroaniline and 2,4-dichloroaniline） with a high selectivity（without cyclohexanol） over a La modified Pd/Al2O3 catalyst.The conversion of the hydrogenation of 2,4,6-trichloroaniline and 2,4-dichloroaniline are both 100%,and the corresponding selectivity of cyclohexanone are 98.6%and 100%（cyclohexanol was not detected） ,respectively,under the optimal reaction conditions. Chloraniline was first underwent hydrodechlorination/N-methylation reactions to form intermediates such as aniline,N-methylaniline,N,N-dimethylaniline,etc.on the surface of the Pd/La-Al2O3 catalyst.Then cyclohexanone was produced from the ring hydrogenation and amino-group hydrolysis/alcoholysis of these intermediates.The presence of Cl in the chloraniline molecular and water in the reaction system is important for the selectivity of cyclohexanone.