The role of KCl in FeCl3-KCl/Al2O3 catalysts with enhanced catalytic performance for ethane oxychlorination

Dalton Trans. 2017 Aug 8;46(31):10433-10439. doi: 10.1039/c7dt01957b.

Abstract

Among the vinyl chloride production processes, ethane oxychlorination is the most economical and environment-friendly process but constrained by the lack of high performance catalysts for industrial applications. In this work, FeCl3-KCl/Al2O3 catalysts with different molar ratios of K/Fe were prepared by a co-impregnation method and applied to ethane oxychlorination. The FeCl3-KCl/Al2O3 catalyst with K/Fe = 2 exhibited enhanced catalytic performance with the highest conversion of C2H6 (99.1%) and the best selectivity to C2H3Cl (74%) under the optimal conditions of 400 °C, C2H6 : HCl : air = 1 : 3 : 5.5 (volume ratio) and GHSV = 4560 h-1. It was found that the enhanced catalytic performance could be attributed to the formation of KFeCl4 from KCl and FeCl3 and the change of the reaction process. Besides, KCl is in favor of weakening the interaction between the active species and support. The reduction activation energy of Fe(iii) → Fe(ii) is efficiently reduced by KCl addition. The FeCl3-KCl/Al2O3 catalyst may be a potential catalyst for industry due to its simple composition and convenient preparation.