Liquid phase kinetic study of the formation and decomposition of methylsulfonyl and cyclohexylsulfonyl radicals in the cyclohexane–MeSO2C1-SO2 System at 150°

The thermally and radiolytically induced chain decomposition of methanesulfonyl chloride (MeSO₂Cl) in liquid cyclohexane (RH) was studied at 150°C. The main products, chlorocyclohexane, sulfur dioxide, and methane, are formed in almost equal yields, and a relatively small amount of methyl chloride is also observed. The formation and addition of SO₂ strongly inhibit the chain decomposition reaction. By kinetic analysis it is shown that the formation of the main products can be explained only in terms of a mechanism that postulates the decomposition of MeSO₂, and that the alternative mechanism of methane and SO₂ formation via the methanesulfinic acid is inconsistent with the kinetic behavior of the system. For the reactions Me + MeSO₂Cl → MeCl + MeSO₂(2b), Me + RH → MeH + R (4), and Me + CCl₄ → MeCCl₄ → MeCl + CCl₃ (15b) the following rate constant ratios are determined; k_2b/k₄=2.17±0.20 and k_2b/k_15b=2.63±0.52. For the reactions R + MeSO₂Cl → RCl + MeSO₂(2a) and R + CCl₄ → RCl + CCl₃ (15a), k_2a/k_15a is equal to 1.55±0.05. In addition the equilibrium constant K₇ for the reaction R + SO₂ ? RSO₂ (7) is estimated as being equal to (9.4±3) × 10³ mole/l.