The role of Form ation Chemically Activated Intermediates on th e Mechan ism and Kinetics of the Reaction of M ethoxy Radical with Hydroxyl Radical

Chemically active species like hydr oxyl radical, methoxy radical (CH۳ O), and hy droxy methyl radical (CH ۲OH) play important role in the atmospheric and combustion processes. Methoxy radical undergoes isomerisation process to produce hydroxy meth yl radical. Both methoxy and hydroxy methyl ra dicals are th e key intermediates in th e combusti on of methanol in oxygen rich regime. The kinetics of the reac tions of CH ۳O or CH۲O H with hyd roxyl radic al has been stu died in som e extent. Me thoxy radical is ۳۶.۶ k J mol-۱ mor e stable than hydroxy m ethyl radical with ۱۲۵.۵ kJ mol-۱ activation energy at the CCS D(T)/Aug-c c-pVTZ lev el of theory. The major product of th e reaction of methox y radical w ith hydrox yl radical is reported to be formaldehyde and water. The reaction is hi ghly exothermic and the products are ۴۰۱.۹ kJ mol-۱ more stable than the reactants. Another pat h for the re action of m ethoxy radic al with hydroxyl radical is formation of a chemically activated CH۳OOH* interme diate, which is ۱۷۴ kJ mol-۱ more stable than the reactants. F ormation of this chemically activated interme diate increas e the possibility of formation of some other products like m ethane, mol ecular oxygen and meth anol.To the best of our knowledge no data is available for the mechanism and fo rmation of these products.This is the purpose of the present work to inv estigate the possibility of formation of CH۳OOH * intermediate and calculating the branching ratio of differ ent channels in this syst em.

کلیدواژه ها:

Kinetics Hydroxyl radical ، Met hoxy radical ، Hydroxy m ethyl radic al