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

Graphical abstract Highlights • Thermodynamic properties of selected asymmetric methyl ethers are obtained. • Rate constants for hydrogen abstraction reactions by NO 2 on asymmetric methyl ethers are calculated. • The effects of ether bond and size of alkyl are investigated. • Bell-Evans-Polanyi correlation is observed in asymmetric methyl ethers and NO 2 systems. Abstract Hydrogen abstraction by NO 2 from asymmetric methyl ethers by NO 2 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 HNO 2 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 NO 2. [ABSTRACT FROM AUTHOR]