Abstract: 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 mayexplain the effect of concentration of salt,such as LiCl,NaCl,KCl,NaNO3,Na2SO4,NH4Cl,on maximum solubization (Φm) of the microemulsion,but can not explain the differences of the effect of these salt on Φm(to see Fig.1).We have found that,the rateQ(Q=z/r) of salt was correlated with the effect of salt on Φm(to seeTab.1).Theory of Rratio can only explain the effect of fraction mass of part alconols,such as noctyl and nheptyl and nhexyl alcohol on Φm,but can not explain the effect of isobutyl alcohol,n butyl alcohol,npentanol and isoamyl alconol on Φm (to see Fig.2).So theory of Rratio has it's limitations in explaination of the phenomenons of solubization of W/O microemulsion.

Key words: Naphthenic acid, Microemulsion, Solubization, Theory of cohesive e nergies (theory of R-ratio), Saponified, Cosurfantant