Theoretical study on the kinetics of OH radical reactions with CH₃OOH and CH₃CH₂OOH

Abstract

The mechanisms and kinetics studies of the OH radical with alkyl hydroperoxides CH(3)OOH and CH(3)CH(2)OOH reactions have been carried out theoretically. The geometries and frequencies of all the stationary points are calculated at the UBHandHLYP/6-311G(d,p) level, and the energy profiles are further refined by interpolated single-point energies method at the MC-QCISD level of theory. For two reactions, five H-abstraction channels are found and five products (CH(3)OO, CH(2)OOH, CH(3)CH(2)OO, CH(2)CH(2)OOH, and CH(3)CHOOH) are produced during the above processes. The rate constants for the CH(3)OOH/CH(3)CH(2)OOH + OH reactions are corrected by canonical variational transition state theory within 250-1500 K, and the small-curvature tunneling is included. The total rate constants are evaluated from the sum of the individual rate constants and the branching ratios are in good agreement with the experimental data. The Arrhenius expressions for the reactions are obtained.

Estimation of rate coefficients and branching ratios for gas-phase reactions of OH with aliphatic organic compounds for use in automated mechanism construction

“…However, it overestimates the reported contribution of H-atom abstraction from the -CH(OOH)-group in the unsaturated isoprene-derived hydroperoxide, 2-hydroperoxy-3-methyl-but-3-en-1ol, reported by St Clair et al 2016, such that the assigned value of F (-OOH) appears to represent a reasonable compromise. The overall rate coefficients and calculated distributions of OH attack in CH 3 OOH and C 2 H 5 OOH at 298 K are also in good agreement with the density functional theory (DFT) calculations of Luo et al (2011), which provides some additional support for the assigned parameters.…”

Kinetics of the Reactions of Methyl Radical with Hydrogen, Methyl and Ethyl Peroxides

“…The calculated geometries of stationary points for the title reactions are given in Figure S1 (Supporting Information). They are consistent with available values in the literature ( [52] for CH 3 OOH and CH 3 OO; [9] for C 2 H 5 OOH, C 2 H 5 OO, CH 2 CH 2 OOH and CH 3 CH 2 O; [53] for CH 2 O, OH, CH 3 CHO, C 2 H 4 , HOO, CH 3 , CH 4 , CH 3 OH and CH 3 O). Compared to the values calculated at B3LYP and M06‐2X theories, the values calculated at MP2 theory are in good accordance with available literature data and the maximum deviations between them are less than 0.015 Å for the bond lengths and no more than 1.1° for the bond angles.…”

“…The calculated vibrational frequencies of the stationary points for the title reactions are listed in Tables S2a–c (Supporting Information). They are in good agreement with available literature data [9,52–53] . The deviations between the calculated and available literature data are within 5.1 %.…”

“…Alkyl and Hydrogen peroxides play a significant role in low‐temperature combustion processes [1–4] and are considered as a temporary pool for various active radical in atmosphere with several hundreds of pptv level, [5–6] responsible for regulating the oxidation capacity of the earth atmosphere and redistributing hydroperoxyl radicals or alkyl peroxy radicals [7–9] . They can be converted into unsaturated ketones or aldehydes which are able to cause various damages to the environment or human [10–13] and involved in the formation of acid rain, acting as oxidants of sulfur dioxide in rain droplets and clouds [14–15] .…”

Theoretical Study on the Dynamics and Kinetics of the Reaction of CH2OH with OH

“…Experimental and computational works are reported on the kinetics of the reaction of OH radical with OCS, − SO 2 , CH 2 O, H 2 O, CO, CH 3 OOH and CH 3 CH 2 OOH . Also, several experimental and computational studies have addressed the reaction of CH 2 OH with O 2 , NO 2 , O­( 3 P), and HBr .…”