The Reaction of OH Radicals with 1,1‐di‐, tri‐ and tetrachloroethylene

TLDR: In this article, the authors investigated the kinetics and product formation of the homogeneous gas-phase reactions of the OH radical with 1,1-di, tri-and tetrachloroethylene, in the pressure range of 0.5-5.6 mbar.

Abstract: The kinetics and product formation of the homogeneous gas-phase reactions of the OH radical with 1,1-di-, tri- and tetrachloroethylene were investigated at temperatures between 298–459 K, in the pressure range of 0.5–5.6 mbar. Measurements were made in a discharge-flow apparatus, using helium as the carrier gas. The OH radical and the reaction products were detected by mass spectrometry. The rate constants were observed to be pressure independent in the case of 1,1-di- and tetrachloroethylene but slightly pressure dependent in the case of trichloroethylene. The temperature dependencies can be expressed by the Arrhenius equation (in units of 1012 cm3 mol−1 s−1). k(T) = (0.136 ± 0.016) exp[(9.5 ± 0.4) kJ mol−1/RT] for 1,1-dichloroethylene, k(T) = (0.470 ± 0.051) exp[(2.0 ± 0.5) kJ mol−1/RT] for trichloroethylene, and k(T) = (3.33 ± 0.19) exp[−(8.6 ± 0.1) kJ mol−1/RT] for tetrachloroethylene. The major products are: CH2OH — CCl2 for 1,1-dichloroethylene; 2,2-dichloroethenol and Cl for trichloroethylene; trichloroethenol, dichloroacetyl chloride, Cl, CHCl2 and phosgene for tetrachloroethylene.