The microemulsion system of HA(2-ethylhexylphosphonic acid mono 2-ethylhexyl ester) / kerosene not containing cosurfactant has been investigated.The physico-chemical properties,such as phase behaviour, conductivity etc. of microemulsion formed by HA-kerosene saponified by different concentrations of sodium hydroxide have been measured . The results show that the properties are different from the microemulsion system containing cosurfactant. The structure of the microemulsion has been discussed. Furthermore, the effect of H2O、 NaCl、 NH4Cl on the properties of microemulsion have also been studied.
