Polar effects in hydrogen abstraction from benzaldehydes. Part IV. Solvent effect on chlorination by sulphuryl chloride

Abstract

Enhancement of the reactivity of benzaldehyde relative to cyclohexane towards sulphuryl chloride at 40° in CCl₄ was demonstrated by modifying the reactivity of the hydrogen-abstractor radical in the rate-determining step with added benzene and t-butylbenzene which are able to complex with atomic chlorine. Relative rates of chlorination of substituted benzaldehydes with SO₂Cl₂ have been determined in benzene, and in 2_M-PhBu^t in CCl₄ at 40°. The Hammett correlations with σ constants (ρ–0·68 and –0·86, respectively) are attributed to the selective benzene and t-butylbenzene π-complexed chlorine atom.