邻氯硝基苯在Pd／C催化剂上加氢反应机理及添加Cu对邻氯苯胺选择性的影响  

Mechanism of hydrogentation of o-chloronitrobenzene over Pd/C and the effect of copper on selectivity of o-chloroaniline in the reaction

作　　者：李峰[1] 李明时[1] 朱建军[1] 单玉华[1] 

机构地区：[1]江苏省精细石油化工重点实验室,江苏工业学院化工系,江苏常州213164

出　　处：《化学研究与应用》2010年第3期311-315,共5页Chemical Research and Application

基　　金：国家自然科学基金资助项目(20976076);教育部留学回国人员科研启动基金资助项目

摘　　要：本文研究了邻氯硝基苯在5％Pd／C催化剂上加氢为邻氯苯胺和苯胺的反应机理。结果表明，在常压下，邻氯苯胺和苯胺的选择性分别为～70％和～30％，且不随转化率增加而变化。在加压（1．0Mpa）条件下，也有类似规律。因此，说明邻氯苯胺和苯胺分别是两个平行反应的产物。通过测定该反应各步骤的初始反应速率，进一步证实了这一结论。在认识反应机理的基础上，制备出可有效抑制脱氯的Cu-Pd／C双金属催化剂。在不加脱氯抑制剂的情况下，可使邻氯硝基苯加氢制备邻氯苯胺的选择性提高到96％以上。Reaction mechanism of hydrogenation of o-chloronitrobenzene to o-chloreaniline and aniline over 5% Pd/C was investigated. It was shown that the selectivity of o-chloroaniline and aniline were - 70% and -30%, respectively, under atomosphere. More importantly, the selectivities remained almost constandy with increasing conversion of o- chloronitrobenzene. Similar results were observed under elevated perssure （ 1.0 Mpa）. These results indicated that o-chloroaniline and aniline were formed from two parallel reactions. The initial reaction rates of diferent reactions were measured, which further confirmed the paralle reaction mechanism. Based on the proposed mechanism, a Cu-Pd/C bimetallic catalyst was prepared and applied in hydrogenation of o-chloronitrobenzene to o-chloroaniline. Thus,selectivity of o-chloroaniline was improved to higher than 96%, owing to the inhibiting effect of copper on hydro-dechlorination reaction.

关 键 词：邻氯硝基苯 邻氯苯胺 催化加氢 反应机理 

分 类 号：O643.32[理学—物理化学]