Substituent effects in the mass spectra of diethyl phenyl phosphates

The mass spectra of diethyl phenyl phosphates show substituent effects with electron‐donating groups favouring the molecular ion M+˙, and the [MC2H4]+˙, [M – 2C2H4]+˙ and [XPhOH]+˙ ions. The [PO3C2H6]+ (m/z 109) and [PO3H2]+ (m/z 81) ions are favoured by electron‐withdrawing groups. Results suggest that the formation of the [XPhC2H3]+˙ ion involves rearrangement of C2H3 to the position ortho to the phosphate group. Ortho effects are also observed.