Unimolecular decomposition of ethyl hydroperoxide: Ab initio/Rice- Ramsperger-Kassel-Marcus theoretical prediction of rate constants

Alkyl hydroperoxides are found to be important intermediates in the combustion and oxidation processes of hydrocarbons. However, studies of ethyl hydroperoxide (CH₃CH₂OOH) are limited. In this work, kinetics and mechanisms for unimolecular decomposition of CH₃CH ₂OOH have been investigated. The potential energy surface of decomposition reactions have first been predicted at the CCSD(T)/6-311+G(3df,2p) //B3LYP/6-311G(d, p) level. The results show that the formation of CH ₃CH₂O + OH via O-O direct bond dissociation is dominant, the branching ratio of which is over 99% in the whole temperature range from 300 to 1000 K, and its rate constant can be expressed as k1 = 9.26 × 10 ⁵² T^-11.91 exp(-26879/T) s^-1 at 1 atm. The rate constants of the reaction CH₃CH₂OOH → CH ₃CH₂O + OH at different temperatures and pressures have been calculated, which can help us to comprehend the reactions of CH ₃CH₂OOH at experimental conditions.