Reactions of Arylsulphonic Esters: Ii. The Alkyl Group

As part of the project outlined in Paper I of this series, we report kinetic data, including Arrhenius parameters, for the solvolysis of a number of alkyl benzene- and toluene-sulphonates in ethanol and in water. The alkyl groups include the α- and β-methylation series: methyl, ethyl, isopropyl, n-propyl, isobutyl, and neopentyl; the straight chain series n-butyl and n-amyl; and a small group of oxygen-containing chains. The observed rates for the α-methylation series parallel those for the bromides and nitrates, and for the β-methylation, those for the bromides. However, it is evident that current interpretations of rate differences observed in the straight chain and oxygenated series cannot be applied with confidence to the benzenesulphonates since the changes in the Arrhenius parameters are larger than the observed differences in the rate.