Radiation-induced dechlorination of pentachloroethane and sym-tetrachloroethane. Reactions of 1,1,2,2-tetrachloroethyl and 1,2,2-trichloroethyl radicals

Abstract

Pentachloroethyl 1,1,2,2-tetrachloroethyl and 1,1,2-trichloroethyl radicals were produced by the reactions of radiolytically generated cyclohexyl radicals with pentachloroethane and sym-tetrachloroethane. The kinetics of the following reactions were studied: c-C6H11+ C2Cl5H →c-C6H11Cl + C2Cl4H (2), c-C6H11+ C2Cl5H →c-C6H12+ C2Cl5(3), C2Cl4H + c-C6H12→C2Cl4H2+ c-C6H11(4), C2Cl4H →C2Cl3H + Cl (5), c-C6H11+ C2Cl4H2→c-C6H11Cl + C2Cl3H2(11), c-C6H11+ C2Cl4H2→c-C6H12+ C2Cl4H (12), C2Cl3H2+ c-C6H12→C2Cl3H3+ c-C6H11(13), C2Cl3H2→C2Cl2H2+ Cl. (14). The following rate expressions were obtained: log10(k2/k3)= 1.40±0.15 –(660±230)/4.576T; log10(k11/k12)= 1.07±0.06 –(3780±120)/4.576T: log10(k5/k4)(mol l.–1)= 5.63±0.07 –(8100±100)/4.576T; log10(k14/k13)(mol l.–1)= 5.91±0.21 –(6900±400)/4.576T. R the gas constant was taken to be 1.9872 cal K–1mol–1 and subsequent activation energies expressed in cal mol–1(1 cal = 4.1855 J).