Heterogeneous catalysis in solution. Part 21. The effect of various carbons on the solvolysis of 2-chloro-2-methyl-1-phenylpropane in 50% v/v ethanol–water

Abstract

The first-order solvolysis of PhCH₂CMe₂Cl in 50% v/v EtOH–H₂O at 40 °C was found to be inhibited by two types of carbon, Hopkin and Williams activated charcoal and Akzo Ketjenblack E.C. Competitive adsorption experiments indicated that the substrate was adsorbed at its phenyl end. The surface solvolysis was found by a combination of kinetic and adsorption measurements to have a rate constant 1/4 as large as the homogeneous solvolysis and a greater activation energy. The main reason for the slower solvolysis of the adsorbed molecules was preferential adsorption of ethanol on the carbon surface. The adsorption isotherm on charcoal of PhCH₂CMe₂Cl in 50% v/v EtOH–H₂O was also derived from the experimental data.