Mass-spectrometric study on ion-molecule reactions of CH5+, C2H5+, and C3H5+ with monosubstituted benzenes carrying a hydroxy group

The gas-phase ion-molecule reactions of CH5+, C2H5+, and C3H5+ with four mo nosubstituted benzenes carrying a hydroxy group in the substituent [PhX:X = OH, CH2OH, CH2CH2OH, and CH(OH)CH3] have been studied under a reactant-ion selective chemical ionization mode of an ion-trap type of GCIWIS. The majo r product channel for PhOH is non-dissociative proton transfer leading to ( M + H)(+) ions, while that for the other three reagents is dissociative pro ton transfer leading to (M + H - H2O)(+) ions in most cases. Small amounts of dissociative alkylation channels are found in some reactions with C2H5and C3H5+. The reaction mechanism is discussed based on the dependence of p roduct-ion distributions on the reaction time and semi-empirical calculatio ns of the energies of intermediates and products.