The interaction of benzoic acid and chloroxylenol with cetomacrogol

Abstract

Abstract The interaction of benzoic acid with the non-ionic surfactant cetomacrogol 1000 has been examined by means of solubility and pH measurements, potentiometric titration and equilibrium dialysis. Solubility measurements and equilibrium dialysis have also been used to assess the interaction of chloroxylenol with cetomacrogol. Following earlier proposals, the interactions have been expressed both in terms of a distribution coefficient for the partition of preservative between the micelles and aqueous phase, and as a ratio of the total preservative concentration to the amount free in the aqueous phase. It is suggested that a more generally useful method is to express the degree of saturation of the aqueous phase with preservative as a function of the degree of saturation of the total system.