The catalyst-free dehydrofluorination of 1,1,1,3,3-pentafluoropropane (HFC-245fa) was investigated both experimentally and theoretically to elucidate the mechanism and kinetics of the reaction. The experimental results demonstrated easier generation of E-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) than HFO-1234ze(Z) under the same reaction conditions within a temperature range of 500–700 °C. When analyzing the geometry, energetics, and kinetic modeling of the reaction at the B3LYP/6−311++G (d,p) level of theory, it was found that the thermodynamic stability of HFO-1234ze(E) is relatively higher than its isomer (HFO-1234ze(Z). Besides, the rate constants of HFO-1234ze(E) were always larger than those of HFO-1234ze(Z) at 400–2000 K, which agreed well with the higher selectivity of HFO-1234ze(E) in the synthetic experiment results. Our theoretical demonstration provides a reference to investigate the mechanism and kinetics of other analogous reactions.

通过实验和理论研究了1,1,1,3,3-五氟丙烷 ( HFC-245fa )的无催化剂脱氟化氢反应，以阐明反应的机理和动力学。实验结果表明，在 500–700 °C 的温度范围内，在相同的反应条件下，E -1,3,3,3-四氟丙烯 ( HFO-1234ze(E) ) 比HFO-1234ze(Z)更容易生成。在 B3LYP/6−311++G (d,p) 理论水平分析反应的几何学、能量学和动力学模型时，发现HFO-1234ze(E)的热力学稳定性相对高于它的异构体 ( HFO-1234ze(Z)。此外，HFO-1234ze(E)的速率常数在 400-2000 K 时总是大于HFO-1234ze(Z)，这与合成实验结果中HFO-1234ze(E)的更高选择性非常吻合。我们的理论论证为研究其他类似反应的机理和动力学提供了参考。