FRAGMENTATION OF METASTABLE MOLECULAR-IONS OF ACETYLANISOLES

The spontaneous unimolecular dissociation reactions of the molecular i ons of ortho-, meta- and para-acetylanisoles have been investigated by mass-analyzed ion kinetic energy spectrometry, high resolution mass s pectrometry and deuterium labelling. Losses of CH3. from the molecular ions of all isomers occur exclusively from the acetyl group. The loss of CH3. for the o-isomer consists of two processes, i.e. one of them is a simple cleavage, and the other is a rearrangement. The latter is not observed for the m- and p-isomers. The loss of H2O from the molecu lar ion is also unique for the o-isomer, and the fragmentation mechani sm is also explored.