Experiments were conducted in a batch reactor under isothermal conditions to study the enhancement of the esterification reaction between ethanol and sulphuric acid with ionic liquid as catalyst. The three catalysts used for the study were 1-butyl 3-methylimidazolium octyl sulphate, 1-ethyl 3-methylimidazolium octyl sulphate and 1-butyl 3-methylimidazolium methyl sulphate. The effect of reaction temperature, catalyst concentration and type of catalyst on conversion of the reactant was studied to obtain the kinetics of the reaction. The conversion levels increased with increasing catalyst concentration and decreased with increasing reaction temperature in the temperature range investigated. The rate data fitted first-order kinetics at high concentrations of the reactant and zero-order kinetics at low concentrations of the reactant, thus exhibiting shifting order-type kinetics. The proposed reaction mechanism suggested the possibility of splitting of the ionic liquid before participating in the reaction. © 2013 © 2013 Indian Institute of Chemical Engineers.