The solubization of the W/O microemulsion of NA（naphthenic acid）/kerosene/NH3· H2O system has been investigated.The effect of salt,cosurfactant （- alcohol） on solubization of the microemulsion has been studied by the theory of cohesive energies（theory of R- ratio）.The results show that theory of R- ratio may explain the effect of concentration of salt,such as LiCl,NaCl,KCl,NaNO3,Na2SO4,NH4Cl,on maximum solubization （Φ m） of the microemulsion,but can not explain the differences of the effect of these salt onΦ m（to see Fig.1）.We have found that,the rateQ（Q=z/r） of salt was correlated with the effect of salt on Φ m（to see Tab.1）.Theory of R- ratio can only explain the effect of fraction mass of part alconols,such as n- octyl and n- heptyl and n- hexyl alcohol onΦ m,but can not explain the effect of isobutyl alcohol,n- butyl alcohol,n- pentanol and isoamyl alconol onΦ m （to see Fig.2）.So theory of R- ratio has it’s limitations in explaination of the phenomenons of solubization of W/O microemulsion.
