Computational Study on the Reaction of β-Hydroxyethylperoxy Radical with HO 2 and Effects of Water Vapor.

The reaction of β-hydroxyethylperoxy radical (β-HEP) and HO 2 with and without water was studied using quantum chemistry and kinetic calculations. The main products are HOCH 2 CH 2 OOH and 3 O 2 for the reaction with and without water, while all other reaction channels can be neglected. The rate coefficients of the reaction follow negative temperature dependence. The pseudo-second-order rate coefficients are 2-4 orders of magnitude smaller for the reaction with saturated water vapor, indicating the negligible contribution of water in this reaction. This is probably also true for other peroxy radicals (except for HO 2 ), indicating that a large part of previous results on the water enhancement of reaction rate coefficients might have overestimated the influence of water.