Rate Coefficients and Mechanistic Analysis for the Reaction of Hydroxyl Radicals with 1,1-Dichloroethylene and trans-1,2-Dichloroethylene over an Extended Temperature Range

Abstract

Rate coefficients are reported for the gas-phase reaction of the hydroxyl radical (OH) with 1,1-dichloroethylene (k1) and trans-1,2-dichloroethylene (k2) over an extended temperature range at 740 ± 10 Torr in a He bath gas. Absolute rate measurements were obtained using a laser photolysis/laser-induced fluorescence (LP/LIF) technique under slow flow conditions. Rate measurements for k1 exhibited complex behavior with negative temperature dependence at temperatures below 640 K, a rapid falloff in rate between 650 and 700 K, and positive temperature dependence from 700 to 750 K. The simple Arrhenius equation adequately describes the data below 640 K and above 700 K and is given (in units of cm3 molecule-1 s-1) by k1(291−640 K) = (1.81 ± 0.36) × 10-12 exp(511 ± 71)/T and k1(700−750 K) = 3.13 × 10-10 exp(−5176/T). Rate measurements for k2 also exhibited complex behavior with a near-zero or slightly negative temperature dependence below 500 K and a near-zero or slightly positive temperature dependence above 50...