Theoretical study on the kinetics for OH reactions with CH3OH and C2H5OH

Abstract

Kinetics and mechanisms for reactions of OH with methanol and ethanol have been investigated at the CCSD(T)/6-311 + G(3df, 2p)//MP2/6-311 + G(3df, 2p) level of theory. The total and individual rate constants, and product branching ratios for the reactions have been computed in the temperature range 200–3000 K with variational transition state theory by including the effects of multiple reflections above the wells of their pre-reaction complexes, quantum-mechanical tunneling and hindered internal rotations. The predicted results can be represented by the expressions k₁ = 4.65 × 10⁻²⁰ × T^2.68 exp(414/T) and k₂ = 9.11 × 10⁻²⁰ × T^2.58 exp(748/T) cm³ molecule⁻¹ s⁻¹ for the CH₃OH and C₂H₅OH reactions, respectively. These results are in reasonable agreements with available experimental data except that of OH + C₂H₅OH in the high temperature range. The former reaction produces 96–89% of the H₂O + CH₂OH products, whereas the latter process produces 98–70% of H₂O + CH₃CHOH and 2–21% of the H₂O + CH₂CH₂OH products in the temperature range computed (200–3000 K).

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Keywords

Theoretical study

Kinetics

OH reaction with CH₃OH and C₂H₅OH

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