Photolysis of, and the reactions of H-atoms with, isopropanethiol

Abstract

Detailed investigation of the photolysis of i-C3H7SH has been carried out in the absence and presence of the inert gas, n-C4H10. A mechanism consisting of three primary photochemical steps: [Formula: see text], [Formula: see text]; [Formula: see text], [Formula: see text]; [Formula: see text],[Formula: see text]; six hot reaction steps and seven thermal reaction steps adequately explains all the experimental observations. As in the case of hot H* atoms both the H-atom abstraction, [Formula: see text], and the SH-displacement, [Formula: see text], reactions occur with thermalized H-atoms, with the rate constant ratio k7/k8 = 19.2 ± 4.3 at 25 °C. The Arrhenius expressions have been determined over the temperature range 25–145 °C, to be: k7 = (4.0 ± 0.7) × 1012 exp [(−1066 ± 43)/RT] and k8 = (2.8 ± 0.6) × 1012 exp[(−2597 ± 114)/RT] cm3 mol−1 s−1. It was found that the overall mechanism for the photolytic decomposition of i-C3H7SH is analogous to that established for C2H5SH in previous investigations.