Barrierless Reactions with Loose Transition States Govern the Yields and Lifetimes of Organic Nitrates Derived from Isoprene.

ABSTRACT: The chemical reaction mechanism of NO addition to two β and δ isoprene hydroxy-peroxy radical isomers is examined in detail using density functional theory, coupled cluster methods, and the energy resolved master equation formalism to provide estimates of rate constants and organic nitrate yields. At the M06-2x/aug-cc-pVTZ level, the potential energy surfaces of NO reacting with β-(1,2)-HO-IsopOO^• and δ-Z-(1,4)-HO-IsopOO^• possess barrierless reactions that produce alkoxy radicals/NO₂ and organic nitrates. The nudged elastic band method was used to discover a loosely bound van der Waals (vdW) complex between NO₂ and the alkoxy radical that is present in both exit reaction channels. Semiempirical master equation calculations show that the β organic

SUBMITTER: Piletic IR 

PROVIDER: S-EPMC6061928 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature