Mass-Spectrometric Study on Ion–Molecule Reactions of CF3+ with PhX [X = H, CH3, and C2Hn (n = 1, 3, 5)] at Near-Thermal Energy

The gas-phase ion-molecule reactions of CF3+ with benzene, toluene, ethylbenzene, styrene, and ethynylbenzene have been studied at near-thermal energy using an ion-beam apparatus. The major product channels are electrophilic addition followed by HF elimination for benzene (93.4 ± 2.2%), toluene (84.3 ± 2.4%), and ethynylbenzene (76.9 ± 0.9%). The dominant product channels for ethylbenzene are electrophilic addition followed by C2H4 and C2H4+HF eliminations (78.9 ± 4.7%), while those for styrene are electrophilic addition followed by one or two HF eliminations and C2H2F2 elimination (91.7 ± 5.4%). Only ethynylbenzene gives an initial adduct ion with a small branching ratio of 6.2 ± 0.4%. As minor product channels, hydride transfer occurs for benzene (6.6 ± 2.2%) and toluene (7.8 ± 1.5%), and charge transfer takes place for toluene (7.9 ± 2.0%), styrene (8.3 ± 1.4%), and ethynylbenzene (6.2 ± 0.4%). The reaction mechanisms are discussed on the basis of product ion distributions and semi-empirical calculatio...