Separation of Mass Law and Solvent Effects in Kinetics of Solvolyses of p-Nitrobenzoyl Chloride in Aqueous Binary Mixtures

Article abstract of DOI:10.1021/jo00239a004

Rates and products for solvolyses of p-nitrobenzoyl chloride in aqueous binary mixtures with acetone, ethanol, and methanol are reported.Product selectivities, S = /, increase in more aqueous media, in contrast to published data for solvolyses of benzoyl chloride.Logarithms of first-order rate constants are relatively insensitive to solvent ionizing power (Y), showing marked dispersions for the three aqueous binary mixtures and unusual rate maxima for aqueous alcohol mixtures.Logarithms of calculated third-order rate constans for solvolyses in aqueous acetone (assuming these solvolyses are second order in water) show a linear Grunwald-Winstein plot (m = -0.18), interpreted as the medium effect.Similarly, third-order rate constants for ethanol and methanol are calculated from solvolyses in the pure alcohols.Rate data in aqueous alcohols are explained quantitavely by an additional third-order pathway (first order in alcohol and in water), and product data are well explained if this process leads to ester.Thus mass law and medium effects of solvent molecules are separated, and it is shown that rate-product correlations of acceptable precision explain the unusual features of these solvolyses.