The reaction rates for the esterification of a substituted phenylacetic acid by phase-transfer catalysis were measured using a constant interfacial area cell. Experiments were performed at different concentrations of aqueous-phase reactant, phase-transfer catalyst, NaOH, and organic-phase reactant. It was shown that the stirring significantly affected the reaction rates. An attempt was made to express the reaction rate as a function of the concentrations of reactive species. The effect of temperature on the reaction was also studied, and the activation energies were evaluated. A possible mechanism was proposed and discussed based on a mixed Makosza and modified interfacial mechanisms.

Interfacial tensions between water/n-hexane and water/toluene in the synthesis of ether-ester compounds by phase-transfer catalysis were measured. These two-phase systems contained phase-transfer catalysts, an aqueous-phase reactant, and/or alkaline. It was shown that the measured data could be well described by the Gibbs adsorption equation coupled with the Langmuir monolayer isotherm. In addition, the interfacial parameters such as the surface excess and adsorption constant determined in one-compound systems allowed one to predict the surface pressure of the present practical liquid-liquid phase-transfer-catalyzed systems. Other interfacial properties of species such as the molecular area and ion-pair dissociation constant were also evaluated.