Effects of Lewis acid catalysts on the esterification kinetics of castor oil with oleic acid

The effects of two Lewis acid catalysts, tin chloride and cobalt chloride, on the kinetics of the esterification reaction between castor oil and oleic acid have been investigated. Uncatalyzed and catalyzed reactions were carried out both in the presence of excess oil and with equivalent amounts of reactants at various temperatures. The reaction, with respect to castor oil concentration, is first-order in all cases, whereas with acid concentration the reaction was observed to change from second-order for the uncatalyzed reaction to first-order for tin chloride-catalyzed and to zero-order for cobalt chloride-catalyzed reactions. The order (with respect to acid) also changed with temperature for the cobalt chloride-catalyzed reaction.