Effect of solvents and mode of solvation in the reaction between benzyl bromide and 2-mercaptobenzothiazole^†

Abstract

The reaction between benzyl bromide and 2-mercaptobenzothiazole has been studied in different protic and aprotic solvents. The kinetic study shows that the reaction is second order with first order dependence each on [benzyl bromide) and [2-mercaptobenzothiazole). Analysis of rate data shows that there is no direct correlation between the rate constant and dielectric constant of the solvent. Correlation of rate data with different solvent parameters like polarisability, nucleophilicity and hydrogen bond acceptor ability, using linear multiple regression analysis shows that the reaction is influenced by these properties of the solvent. From the regression coefficients, information on the mode of solvation of the reactants and the transition state is obtained. The reaction has also been studied at different temperatures and the thermodynamic parameters <img src='/image/spc_char/delta.gif' border=0><i>H</i><img src='http://www.niscair.res.in/jinfo/equation40.gif' border=0>, <img src='/image/spc_char/delta.gif' border=0><i>S</i><img src='http://www.niscair.res.in/jinfo/equation40.gif' border=0> and <img src='/image/spc_char/delta.gif' border=0><i>G<i><img src='http://www.niscair.res.in/jinfo/equation40.gif' border=0> are computed.