Abstract
The kinetics of the reaction of benzenesulphonyl chloride with twentyfive carboxylate ions, R.COO, in 2% dioxan are reported. Eight compounds are accommodated in either a Bronsted-type or a σ− plot. Pivalate and formate ions require a linear combination with Taft's steric factor, Es- Although Es has been shown [1] to be related to r, where r is the radius of a symmetrical group, R3C, Es correlates just as well with r-1, as predicted by the Born equation for steric inhibition by solvent exclusion. Steric effects are shown using the methods previously applied to a priori calculations of electrostriction [2], to be due to steric exclusion of solvent from the vicinity of carboxy-group.