CF3I Synthesis Catalyzed by Activated Carbon: A Density Functional Theory Study

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• 作者：Yingjie Hu ; Taiping Wu ; Weizhou Liu ; Liyang Zhang ; Renming Pan
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：March 13, 2014
• 年：2014
• 卷：118
• 期：10
• 页码：1918-1926
• 全文大小：669K
• 年卷期：v.118,no.10(March 13, 2014)
• ISSN：1520-5215

文摘

A revised reaction mechanism of CF₃I synthesis catalyzed by activated carbon is investigated with quantum chemistry methods using density functional theory (DFT). The adsorption configurations of possible intermediates are carefully examined. The reaction pathway and related transition states are also analyzed. According to our calculations, first, the dehydrofluorination of CHF₃ is catalyzed by 鈭扖OOH groups, which possesses the highest barrier and is accordingly identified as the rate-determining step. Second, the difluorocarbene disproportionation over graphite (001) surface proceeds instead of dimerization. The next reaction steps involving the association of fluoromethine and trifluoromethyl, the fluorine abstractions between intermediates and the iodine abstractions by the desorbed CF₃ and CF₂CF₃ from molecular iodine are also feasible over graphite (001) surfaces. It is also found that the coke deposition in experiments is due to the fluorine abstraction from fluoromethine. This revised mechanism is in agreement with available experimental data and our theoretical computations.