Vol. 3, Issue 1, Part E (2017)

Abstract
The kinetics of the reaction between p-Toluene sulfonyl Chloride (Tosyl chloride – TsCl) with α-Hydroxy acids in the presence of Pyridine has been studied at 293, 303 and 313 K in protic and aprotic solvents. Variations in reaction rate as well as activation parameters have been interpreted on the basis of solvation and dielectric properties of the solvents. Thermodynamic parameters such as activation energy (Ea), enthalpy of activation (ΔH‡), free energy of activation (ΔG‡) and entropy of activation (ΔS‡) have been evaluated from the rate data. The isokinetic relationship has been verified. Analysis of activation energy, enthalpy, entropy and free energy reveals that solvation of transition state is larger in polar solvents which restrict the bond formation process. All reactions have appreciable negative entropy of activation which strongly supports the bimolecular nucleophilic displacement mechanism of these reactions.