A Hierarchical Theoretical Study of the Hydrogen Abstraction Reactions of H2/C1-C4 Molecules by the Methyl Peroxy Radical and Implications for Kinetic Modeling

Shenying Xu; Jinhu Liang; Shutong Cao; Ruining He; Guoliang Yin; Quan-De Wang

doi:10.1021/acsomega.1c06683

A Hierarchical Theoretical Study of the Hydrogen Abstraction Reactions of H₂/C₁-C₄ Molecules by the Methyl Peroxy Radical and Implications for Kinetic Modeling

ACS Omega. 2022 Mar 1;7(10):8675-8685. doi: 10.1021/acsomega.1c06683. eCollection 2022 Mar 15.

Authors

Shenying Xu¹, Jinhu Liang^{1

2}, Shutong Cao², Ruining He², Guoliang Yin¹, Quan-De Wang³

Affiliations

¹ Faculty of Materials and Chemical Engineering, Yibin University, Yibin, Sichuan 644000, People's Republic of China.
² School of Environment and Safety Engineering, North University of China, Taiyuan 030051, People's Republic of China.
³ Jiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization, Low Carbon Energy Institute, China University of Mining and Technology, Xuzhou 221008, People's Republic of China.

Abstract

The hydrogen atom abstraction by the methyl peroxy radical (CH₃O₂) is an important reaction class in detailed chemical kinetic modeling of the autoignition properties of hydrocarbon fuels. Systematic theoretical studies are performed on this reaction class for H₂/C₁-C₄ fuels, which is critical in the development of a base model for large fuels. The molecules include hydrogen, alkanes, alkenes, and alkynes with a carbon number from 1 to 4. The B2PLYP-D3/cc-pVTZ level of theory is employed to optimize the geometries of all of the reactants, transition states, and products and also the treatments of hindered rotation for lower frequency modes. Accurate benchmark calculations for abstraction reactions of hydrogen, methane, and ethylene with CH₃O₂ are performed by using the coupled cluster method with explicit inclusion of single and double electron excitations and perturbative inclusion of triple electron excitations (CCSD(T)), the domain-based local pair-natural orbital coupled cluster method (DLPNO-CCSD(T)), and the explicitly correlated CCSD(T)-F12 method with large basis sets. Reaction rate constants are computed via conventional transition state theory with quantum tunneling corrections. The computed rate constants are compared with literature values and those employed in detailed chemical kinetic mechanisms. The calculated rate constants are implemented into the recently developed NUIGMECH1.1 base model for kinetic modeling of ignition properties.