FRAGMENTATION PROCESSES OF 1,2-DIPHENOXYETHANE AND 2-PHENOXYETHANOL BY ELECTRON-IMPACT

The unimolecular fragmentation processes of 1,2-diphenoxyethane (1) an d 2-phenoxyethanol (2) upon electron impact were investigated by a com bination of mass-analyzed ion kinetic energy (MIKE) spectrometry, deut erium-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 fr om 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-dihydroben zofuran (C8H8O, 3). The metastable 2(+.) ion eliminates C2H4O and C2H3 O to produce product ions at m/z 94 (C6H6O+., 7(+.)) and 95 (C6H7O+) w ith single and double hydrogen atom transfer, respectively. These reac tions occur through some complex rearrangement reactions.