Mass spectra of halogenated esters. 7. Methyl esters of 2‐chloro C2C20n‐alkanoic acids

Abstract

AbstractThe mass spectral fragmentation of a homologous series of methyl esters of 2‐chloro n‐alkanoic acids ranging from acetic (C2) to eicosanoic (C20) acid on electron impact has been investigated. The fragmentation pathways were elucidated with the aid of the first field‐free region metastable ions, the results being presented with one compound, i.e. with ionized methyl 2‐chloro‐octauoate. Owing to the Cl/H exchanges and to the formation of the non‐chlorinated parent esters prior to the fragmentations the spectra show the peak pairs with and without the chlorine atom. The effects become more evident with increasing chain length; shown most visually by the abundance ratios of the McLafferty rearrangement ions atm/z108/110 and 74, and fragments at m/z121/123 and 87.