Hydrogen abstraction by NO2 from asymmetric methyl ethers: A theoretical investigation

Abstract

Hydrogen abstraction by NO2 from asymmetric methyl ethers by NO2 is theoretically investigated based on first-principles calculations in order to constrain their combustion models, including methyl ethyl ether(MEE), methyl n-propyl ether (MNPE), methyl i-propyl ether (MIPE), methyl n-butyl ether (MNBE), and methyl t-butyl ether (MTBE). We obtain the rate constants and branching ratios at 500–2000 K, and the dependence of reactivity on ether sizes and the reaction sites on the ethers. The cis-HONO channel is the most important one, followed by the HNO2 and trans-HONO channels. On the hand, the size of alkyl and the reaction site significantly affect the reactivity. Hydrogen abstraction mainly occurs at the C site (adjacent to the ether bond) of the long-chain alkyl. Moreover, the linear Bell-Evans-Polanyi correlation is observed for the hydrogen abstraction reactions between the asymmetric methyl ether and NO2.