Investigation of unimolecular decomposition and isomerisation reactions of some metastable carboxonium ions in the gas phase

Abstract

The C₃H₅O⁺ cations generated from CH₂CH·CH(OH)CH₃, CH₂CH·O·CH₂·CH₃, [graphic omitted] and CH₃·[graphic omitted] have been shown to isomerise to the same structure or mixture of structures before fragmentation with a rate constant in the region 10⁵–10⁶ sec.^–1. However, the C₃H₅O⁺ ion generated from CH₃·CH₂·CO₂Me remains structurally distinct. Protonated carboxylic acid ions generated from the n-butyl esters of acrylic, crotonic, and propionic acids have been shown to remain distinct from isomeric ions before dehydration to the corresponding acylium ions in a metastable transition.