Comparative Study on the H-Abstraction Reactions of Isopropyl Acetate and Propyl Acetate by HO2 and OH Radicals

Mengjiao Gao; Jiuning He; Lilan Tian; Lei Chen; Shunping Shi; Changhua Zhang; Deliang Chen

doi:10.1021/acs.jpca.4c00794

Comparative Study on the H-Abstraction Reactions of Isopropyl Acetate and Propyl Acetate by HO₂ and OH Radicals

J Phys Chem A. 2024 Apr 11;128(14):2825-2842. doi: 10.1021/acs.jpca.4c00794. Epub 2024 Apr 2.

Authors

Mengjiao Gao¹, Jiuning He¹, Lilan Tian¹, Lei Chen¹, Shunping Shi¹, Changhua Zhang², Deliang Chen³

Affiliations

¹ College of Mathematics and Physics, Chengdu University of Technology, Chengdu, Sichuan 610059, China.
² Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
³ School of Physics and Electronic, Guizhou Education University, Guiyang, Guizhou 550018, China.

PMID: 38563141
DOI: 10.1021/acs.jpca.4c00794

Abstract

Isopropyl acetate (IPA) and propyl acetate (PA) are recognized as promising biofuels suitable for applications as fuel additives and biodiesel models. The H-abstraction reactions with radicals stand out as the fundamental initiating reactions in the combustion kinetic models for IPA and PA. In the present work, the kinetic calculations of IPA and PA plus HO₂ and OH radicals were investigated at M06-2X/cc-pVTZ//G4, M08-HX/maug-cc-pVTZ, and CCSD(T)/jul-cc-pVTZ levels. The thermodynamic calculations were obtained based on the G4 and CBS-APNO methods. Rate coefficients were calculated using both transition state theory and canonical variational transition state theory with tunneling correction at the temperature range of 250-2000 K. The total rate constants for the IPA + OH system were fitted as follows: k = 0.4674 × T^3.927 exp(2128/T) (cm³ mol^-1 s^-1), and for the PA + OH system, the total rate constants were determined using the following equation: k = 0.0161 × T^4.373 exp(2220/T) (cm³ mol^-1 s^-1). The rate coefficients of IPA + OH reactions determined based on the M08-HX/maug-cc-pVTZ level effectively replicate the experimental data, while H-abstraction rate coefficients of PA + OH by the CCSD(T)/jul-cc-pVTZ method accurately reproduce the experimental data. Refining the H-abstraction rate coefficients in the kinetic mechanism of PA, as proposed by Dayma et al. [Proc. Combust. Inst. 37 (2019) 429-436], has been achieved through incorporating the present calculated data, leading to the development of a revised mechanism. The validation of the updated mechanism against jet-stirred reactor data is presented, showcasing its effective performance in predicting JSR data.