合成气在Rh(111)上转化为乙醇的机理的键级守恒研究

Bond-Order-Conservation Model Study of the Mechanism of Ethanol Formation from Syngas Conversion on Rh(111)

Rh上乙醇的生成机理,目前主要有两类.一是Ichikawa等为代表提出的“CO解离—CH_x(x=2或3)—乙酰基—乙醇”机理;另一是蔡启瑞等的“CO缔合—甲酰基(金属氧卡宾)—卡宾—乙烯酮—乙酰基—乙醇”机理.本文用Shustorovich的键级守恒—Morse势(BOC-MP)

Bond-order-conservation-Morse-potential approach has been used to study the mechanism of ethanol formation from syngas conversion on Rh (111). The results of our calculation show that the reaction for syngas on Rh may be considered through an associative mechanism in which the C2 oxygenates such as ethanol etc. are mainly produced by carbon monoxide (CO) insertion into carbene (CH2) and acetyl is mainly formed by the hydrogenation of ketene (CH2CO) intermediate. The possible rate- determining step (RDS) involved in ethanol formation is believed to be the hydrogenation of CO into formyl (HCO). In addition, the path of formation of CHx species is also discussed.