Ab initio-based kinetics of hydrogen atom abstraction from methyl propionate by H and CH3 radicals: a biodiesel model

• Published in: Structural chemistry Vol. 32; no. 5; pp. 1857 - 1872
• Main Authors: Al-Otaibi, Jamelah S., Mahmoud, Mohamed A. M., Almuqrin, Aljawhara H., El-Gogary, Tarek M., Abdel-Rahman, Mohamed A., El-Nahas, Ahmed M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2021; Springer Nature B.V
• Subjects: Biodiesel fuels; Chemistry; Chemistry and Materials Science; Computer Applications in Chemistry; Density functional theory; Kinetics; Original Research; Oxidation; Physical Chemistry; Radicals; Rate constants; Theoretical and Computational Chemistry; Ab initio; Methyl propionate; Hydrogen atom abstraction; DFT; Rate constant; Biodiesel
• ISSN: 1040-0400; 1572-9001
• DOI: 10.1007/s11224-021-01746-6

The kinetics of hydrogen atom abstraction from methyl propionate ( MePr ), a biodiesel model, by • H and • CH 3 radicals, have been studied. Here, we employ density functional theory (BB1K, BMK, M06-2X, M08-HX, and ω B97XD) and ab initio (MP2, CBS-QB3, and G3) calculations. Rate coefficients of each of six-bimolecular reaction pathways of MePr oxidation were calculated using the conventional transition state theory (TST) with Eckart (Eck) tunneling correction over a wide temperature range, 700-1600 K at pressure 1.0 atm. Branching ratios analysis of different reaction channels indicates that abstraction of H atom from C α is the most dominated route for MePr fuel consumption. However, rate constants of H-atom abstraction from the terminal methyl groups increase with rising of temperature for both • H and • CH 3 radicals.