AbstractThe effect on the interfacial tension of the water toluene system has been studied at 25 °C in the presence of four phase‐transfer catalysts i.e. tricaprylmethyl ammonium chloride, hexadecyltrimethyl ammonium chloride, hex‐adecytrimethyl ammonium bromide and hexadecyltributyl phosphonium bromide. The interfacial tension of aqueous phenol/resorcinol‐toluene in the presence and absence of tricaprylmethyl ammonium chloride has also been reported. Attempt has been made to elucidate the change in volumetric rate of extraction with different catalysts for two phase reactions, on the basis of interfacial t