Ion-Molecule Reactions in Isopropanol: Implications for Its Radiolysis.

The photoionization of isopropanol (-PrOH) at 11.7 eV has been investigated in the NBS high pressure photoionization mass spectrometer over the pressure range 0.1 to approximately 200 millitorr. The major primary ion, CHCHOH, reacts with a total rate coefficient of 1.1 ±0.1× 10 cm/mole-cule-s to yield mainly (-PrOH)H and CH(-C3 H)COH. At pressures in excess of a few millitorr consecutive reactions of (-PrOH)H and CH(-CH7)COH were also detected, including the overall dehydration process These data are interpreted in light of a recent radiolysis study, and a thermal cationic chain mechanism for production of (-CH)O consistent with those results is proposed. The value for the proton affinity of SF is also discussed in some detail.