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

Abstract

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 -COOH 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.

Density Functional Theory Study on Fluorine Abstraction of the CF3I Catalytic Synthesis

“…根据已有的实验及理论研究, CF 及 CF 3 可以缔合生 成吸附于 graphite(001)表面的 CFCF 3 , 实现碳链的增 长 [12,15] . Figure 2 Proposed reaction pathways for the generation of CF 3 and CF 4 吸附于 graphite(001)表面的 CFCF 3 和 CF 2 , 如图 3 所示.…”