The mass spectrum of isopropyl o‐toluate

Abstract

The formation of an [M + 1]+ ion and the fragmentation of isopropyl o‐toluate have been investigated by the deuterium labelling technique and kinetic energy release measurements. The hydrogen atom involved in the [M + 1]+ ion formation does not originate from a specific part of the molecule, but from all parts. A small amount of hydrogen exchange between the secondary carbon atom in the isopropyl group and the carbon atoms in the tolyl group takes place prior to decomposition of the molecular ion into the m/z 136 ion by a McLafferty rearrangement. Either almost complete scrambling of the hydroxyl hydrogen atom and the methyl hydrogen atoms in tolyl group or an almost equilibrated exchange of the hydroxyl hydrogen atom with one of the remaining hydrogen atoms in tolyl group also takes place prior to the elimination of a water molecule from the intermediate m/z 136 ion.