DISTINGUISHING BETWEEN SOLVATION EFFECTS AND MECHANISTIC CHANGES. EFFECTS DUE TO DIFFERENCES IN SOLVATION OF AROMATIC RINGS AND ALKYL GROUPS

Solvolytic rate constants at 25 o C are reported for p-methoxybenzyl chloride (1) in aqueous binary mixtures with acetone, acetonitrile, dioxane, dimethyl sulfoxide, ethanol, methanol, and 2,2,2-trifluoroethanol and for benzoyl chloride and p-methoxybenzoyl chloride (2) in aqueous acetonitrile and aqueous dioxane. Product selectivities are reported for solvolyses of 1 in aqueous ethanol and methanol. Logarithms of rate constants for solvolyses of 2 correlate linearly with solvolyses of 1 (unit slope and only a small «dispersion» ― the tendency for the various binary mixtures to show separate correlations), showing that the solvation requirements of S N 1 reactions of aromatic carboxylic acid chlorides are very similar to those of benzylic chlorides