Unveiling the low-temperature oxidation mechanism of a carbon-neutral fuel – Monoglyme via theoretical study

Monoglyme is a promising carbon-neutral for engines due to its renewability, compatibility with existing infrastructure, high energy content and cetane number, etc. However, its low-temperature oxidation mechanism is not well understood, which hinders its application in advantage combustion technologies. Therefore, this study carried out an in-depth theoretical analysis to bridge this gap in knowledge. All potential reaction pathways related to oxygen addition, hydrogen transfer, concerted elimination, and QOOH decomposition were identified using the density functional theory method. The corresponding rate constants were calculated by solving the time-dependent master equation based on the Rice-Ramsperger-Kassel-Marcus theory in conjunction with the transition state theory, and were subsequently fitted to Arrhenius expressions. It is discovered that the oxygen addition to the monoglyme radical formed by dehydrogention from the intermediate site is more competitive than that from the first site. The QOOH formed by the initial adduct RO2 via the 6-member ring transition state exerts a stronger impact on the second oxygen addition of monoglyme than that via the 5, 7, and 9-member ring transition states. After comparing the simulated and measured concentration distribution of the key substances during the oxidation of monoglyme in a jet-stirred reactor, the reliability and accuracy of the established kinetic model was confirmed.