Hydrogen shift isomerizations in the kinetics of the first and second oxidation mechanism of diethyl ether combustion

Abstract

The kinetics of ROO and OOQOOH radicals play an important role in simulating the ignition behavior of fuel during low-temperature combustion. Diethyl ether (DEE) was chosen in the present work because of its typical and representative character. In this work, we use the multi-structural torsional (MS-T) and multi-structural local quansi-harmonic (MS-LQH) methods to deal with multiple conformations and coupled torsion for structures of reactant, transition state and products, and use the multi-structure variational transition state theory (MS-VTST) to perform dynamic calculations for hydrogen shift isomerizations. Our results indicate that the multistructural anharmonicity effect plays a crucial role in determining the accuracy of the thermodynamic and kinetic quantities. Morever, the kinetics calculations indicate that rate constants for intramolecular hydrogen abstraction in the first oxidation mechanism (ROO → QOOH) and the second oxidation mechanism (OOQOOH → Products) exhibits different feature. This work will be helpful for understanding the oxidation mechanism of diethyl ether combustion.