Fragmentation processes of 1,2-diphenoxyethane and 2-phenoxyethanol by electron impact



The unimolecular fragmentation processes of 1,2-diphenoxyethane (1) and 2-phenoxyethanol (2) upon electron impact were investigated by a combination of mass-analyzed ion kinetic energy (MIKE) spectrometry, deuterium-labelling, high resolution mass spectrometry, and kinetic energy release (KER) measurement. The MIKE spectrum and the KER measurement indicate that the predominant fragment ion at m/z 120 was generated from metastable 1 ions via loss of a phenol molecule (C6H6O, 7), and that it has the same structure as the molecular ion of 2,3-dihydrobenzofuran (C8H8O, 3). The metastable 2 ion eliminates C2H4O and C2H3O to produce product ions at m/z 94 (C6H6O, 7) and 95 (C6H7O+) with single and double hydrogen atom transfer, respectively. These reactions occur through some complex rearrangement reactions.