摘要
采用原位红外测试技术结合化学捕获方法研究了Cu-Zn-Mg-K催化剂上合成低碳混合醇的反应机理。用动态技术提高表面物的浓度,增强其红外信息和提高它们的响应速度。捕获剂CH_3I和CH_3OH以脉冲方式引入原位红外池,分别捕获到一些较关键的C_2中间物:表面乙酰基、表面乙酸盐、乙烯酮和烯醇盐。利用脉冲-原位红外测试技术,观测了从C_1中间物到C_2中间物演变的动态过程,同时还考察了甲醇对低碳醇合成的影响。指出在Cu-Zn-Mg-K上低碳醇的合成是通过CO插入碳链递增这种反应途径实现的。
The mechanism of higher alcohol synthesis on Cu-Zn-Mg-K catalysts was monitored by in situ IR chemical trapping technique . The dynamic technique was used to increase the surface concentration and response rate of surface intermediates, thereby to increase their IR signal intensity. Pulse injection of CH3I and CH3OH into the in situ cell resulted in the appearance of some crucial C2 intermediates in the reaction, such as surface acctyl, acetate, ketene and enolate . Meanwhile, the pulse in situ technique was used to observe the evolution from primary species to C2 intermediates and the influence of methanol on higher alcohol synthesis. The results indicated that higher alcohol synthesis over Cu-Zn-Mg-K occurred via a classical CO insertion mechanism.
