摘要
1.前言 同位素效应是研究化学反应历程的一种有效方法。当反应键被同位素取代后,产生的同位素效应对于确定反应历程中的速控步聚可提供重要信息。本文在一系列铑基催化剂上,分别用H_2,D_2和CO进行合成甲醇及乙醇反应,首次观察到该反应具有显著的氘逆同位素效应。根据这一结果,结合我们先前提出的合成气反应机理,对铑基催化剂上甲醇及乙醇合成反应的可能的速控步骤作了初步探讨。
A series of syngas conversion reactions with the substitution of D2 for H2 were carried out to study the isotope effect of deuterium. Noticable deuterium inverse isotope effects for the methanol and ethanol formation were observed for the first time, which was interpreted from the transition state theory. It is believed that the kinetic isotope effect of hydrogen/deuterium adsorption in rate-determining step (RDS), rather than the thermodynamic one, is responsible for the overall inverse isotope effect. The possible RDS involved in methanol formation was supposed to be the first step of
hydrogenation, i. e. , CO + H→HCO. As deuterium inverse isotope effects for the ethanol and
methanol formation are displayed simultaneously, the RDS involved in ethanol formation seems to be the step of hydrogenation (or deuteration) also.
出处
《分子催化》
EI
CAS
CSCD
1992年第2期156-159,共4页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金资助课题
关键词
铑基
催化剂
甲醇
乙醇
氘同位素
Rhodium-based catalysts, Methanol and ethanol synthesis, Deuterium isotope effects, Reaction mechanism.
