Molecular complexes. Part 12.—Use of phase distribution and nuclear magnetic resonance methods to elucidate the mechanism of the acetone + benzene reaction

Abstract

The results of studies of the acetone + benzene interaction obtained from a phase distribution technique and the conventional n.m.r. approach are compared. This reveals that the conventional n.m.r. approach to studies of molecular complexes can be misleading. In resolving the inherent problems a mechanism for the acetone + benzene reaction is proposed. The reaction is studied in the presence of carbon tetrachloride and cyclohexane separately. It is shown that whereas carbon tetrachloride is reactive towards benzene, cyclohexane is less so and that data obtained by both experimental techniques using this material as solvent provide values for the equilibrium quotient, K_x, and aromatic induced shift, Δ_c, which are in good agreement.