Addition of ethyl radicals to carbon monoxide. Kinetic and thermochemical properties of the propionyl radical

Azoethane was irradiated in the presence of carbon monoxide in the temperature range of 238 to 378 K. Kinetic parameters for the addition of ethyl radicals to carbon monoxide and for the decomposition of propionyl radicals were determined. The rate constants were found to be log k (cm 3 mol −1 sec −1 ) = 11.19 ‐ 4.8/θ and log k (sec −1 ) = 12.77 ‐ 14.4/θ, respectively. Estimated thermochemical properties of the propionyl radical are ΔH f 0 = ‐10.6 ± 1.0 kcal mol −1 , S 0 = 77.3 ± 1.0 cal K −1 mol −1 , and D (C 2 H 5 COH) = 87.4 kcal mol −1 .