Micellization in aqueous solutions of monoalkyl phosphate salts

The micellization of the mono-salts of octyl, decyl, and dodecyl phosphates and of the di-salts of dodecyl phosphate have been studied in aqueous solutions by conductivity methods. The effects of temperature, salt concentration, counterion type, and chain length have been examined. The mono-salts of the alkyl phosphates show properties similar to those of fatty acid soaps and alkyl sulfates. The di-salts show rather different counterion and temperature effects. The solubility diagrams for the mono-salts are anomalous and are explained in terms of the preferred precipitation of stable solid salts of the composition RPO4H2-RPO4HM where M is an alkali metal.