Mass-Spectrometric Study on Ion-Molecule Reactions of CF3+ with Monosubstituted Benzenes Carrying a Carbonyl Group at Near-Thermal Energies

Article abstract of DOI:10.1246/bcsj.69.1055

The gas-phase ion-molecule reactions of CF₃⁺ with five monosubstituted benzenes carrying a carbonyl group (PhCOX: X=H, CH₃, C₂H₅, OCH₃, OC₂H₅) have been studied at near-thermal energies using an ion-beam apparatus. The major product channel for PhCHO, PhCOCH₃, and PhCOOCH₃ is electrophilic addition to the O-atom leading to initial adduct ions, which are 80.3 - 95.0% of the total product ions. Although no initial adduct ions are observed for PhCOC₂H₅ and PhCOOC₂H₅, major product ions are formed by electrophilic addition to the O-atom followed by dissociation and molecular eliminations. The reaction mechanism is discussed based on product ion distributions and semi-empirical calculations of the energies of intermediates and products. The results obtained are compared with reported-ion-cyclotron-resonance data for aliphatic carbonyl compounds.