Mass-spectrometric study on ion-molecule reactions of CH5+, C2H5+, and C3H5+ with C9-C19 alkylbenzenes in an ion trap

Article abstract of DOI:10.1246/bcsj.75.241

Chemical ionization of alkylbenzenes (PhC_xH_{2x + 1} = M: x = 3-13) by the CH₅⁺, C₂H₅⁺, and C₃H₅⁺ ions has been studied under a reactant-ion selective mode of an ion-trap type of GC/MS. The dominant product ions for short-chain reagents (x < 7) were [M + H]⁺, [Phil + H]⁺, and C_xH_{2x + 1}⁺ ions, produced through proton-transfer to benzene ring. On the other hand, the dominant product ions for long-chain reagents (x ≥ 7) were C_yH_{2y + 1}⁺ (y < x) and PhC_yH_2y⁺ (y ≤ x) ions. The former ions are produced through the attack of the reactant ions on the alkyl chain and/or the benzene ring, while the latter ones are exclusively formed through the attack of the reactant ions on the alkyl chain. Major formation processes of C_yH_{2y + 1}⁺ and PhC_yH_2y⁺ ions in each reaction were discussed on the basis of observed distributions and calculated thermochemical data.