From electronic structure to model application of key reactions for gasoline/alcohol combustion: Hydrogen-atom abstraction by CH3OȮ radicals

Caiyu Yang, Jin Tao Chen, Xincheng Zhu, Xin Bai, Yang Li, Kiran K. Yalamanchi, S. Mani Sarathy, S. Scott Goldsborough, Song Cheng*, Henry J. Curran, Chong Wen Zhou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Hydrogen atom abstraction by methyl peroxy (CH3OȮ) radicals can play an important role in gasoline/ethanol interacting chemistry for fuels that produce high concentrations of methyl radicals. Detailed kinetic reactions for hydrogen atom abstraction by CH3OȮ radicals from the components of FGF-LLNL (a gasoline surrogate) including cyclopentane, toluene, 1-hexene, n-heptane, and isooctane have been systematically studied in this work. The M06–2X/6–311++G(d,p) level of theory was used to obtain the optimized structure and vibrational frequency for all stationary points and the low-frequency torsional modes. The 1-D hindered rotor treatment for low-frequency torsional modes was treated at M06–2X/6–31G level of theory. The UCCSD(T)-F12a/cc-pVDZ-F12 and QCISD(T)/CBS level of theory were used to calculate single point energies for all species. High pressure limiting rate constants for all hydrogen atom abstraction channels were performed using conventional transition state theory with unsymmetric tunneling corrections. Individual rate constants are reported in the temperature range from 298.15 to 2000 K. Our computed results show that the abstraction of allylic hydrogen atoms from 1-hexene is the fastest at low temperatures. When the temperature increases, the hydrogen atom abstraction reaction channel at the primary alkyl site gradually becomes dominant. Thermodynamics properties for all stable species and high-pressure limiting rate constants for each reaction pathway obtained in this work were incorporated into the latest gasoline surrogate/ethanol model to investigate the influence of the rate constants calculated here on model predicted ignition delay times.

Original languageEnglish (US)
Pages (from-to)415-423
Number of pages9
JournalProceedings of the Combustion Institute
Volume39
Issue number1
DOIs
StatePublished - Jan 2023

Bibliographical note

Publisher Copyright:
© 2022

Keywords

  • Gasoline/ethanol interacting chemistry
  • Hydrogen atom abstraction reaction
  • Kinetic
  • Methyl peroxy radical
  • Thermochemistry

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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