Theoretical study of mechanisms and kinetics of reactions of the O(3P) atom with alkyl hydroperoxides (ROOH) where (R = CH3 & C2H5)

• Published in: Computational and theoretical chemistry 2022-02, Vol.1208, p.113547, Article 113547
• Main Authors: Guleria, Kanika, Subramanian, Ranga
• Format: Article
• Language: English
• Subjects: Alkyl hydroperoxides; Arrhenius plots; CVT/SCT; Hindered rotations; Potential energy surfaces; Rate coefficients
• ISSN: 2210-271X
• DOI: 10.1016/j.comptc.2021.113547

[Display omitted] •All reaction pathways of CH3OOH + O(3P) and CH3CH2OOH + O(3P) reactions are spontaneous in nature.•Hydrogen abstraction from CH3 group of CH3CH2OOH is endothermic in nature. All other reaction pathways are exothermic.•Hydrogen abstraction from OH group of CH3OOH and CH3CH2OOH are the main reaction pathways as having highest branching ratios.•Tunneling is minimal for OH abstraction pathways. An analysis of O(3P) reaction mechanisms and kinetics with CH3OOH and CH3CH2OOH has been examined. Potential energy diagrams for the named reactions have been evaluated at the W1 and CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ levels of theory. For the two reactions, a total of seven abstraction channels have been described. The reaction enthalpies and standard reaction Gibbs free energy are calculated at the W1 level. The kinetic study is conducted within the temperature range of 210–350 K using transition state theory (TST), TST with Wigner correction (TST/W), and TST with zero curvature tunneling (TST/ZCT). The rate coefficients were also calculated using canonical variational transition state theory (CVT), CVT with zero curvature tunneling (CVT/ZCT), and CVT with small curvature tunneling (CVT/SCT). Branching ratios have been computed using the CVT/SCT rate coefficients. Hydrogen abstraction from the hydroxyl group is identified as a significant pathway in both reactions.