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Abstract The distribution of aniline, o-,m-, and p-ethoxyaniline between both petroleum ether, and aqueous solutions of NaOl of different concentrations, at different temperatures, was studied. Petroleum ether ( b.p. 90° - 130°0 ) was used as an extracting solvent because benzene leads to high distribu- tion coefficients.(54) 70r accuracy in determining distribution coefficients, the volumes of the two phases were arranged so as to keep the amount of amine in the aqueous phase approximately equal to that amount present in the organic phase, in which it was estimated, since the formar was found by difference. The amine in the organic layer was estimated by ultra - violet absorption spectrophotometry. In the distribution coefficient measurements, the amine concentrations were arranged so as to give an equilibrium amine concentration in the non-aqueous phase nearly equal to that obtained in dissociation constant measurements, in ordor to minimize any errors due to association, hydration, and other distributing factors(15). The distribution coefficients mp/ma’ in terms of molali ties ot the amine, bet’1(een \)et-ro1.eum. e”’t.he-r end. eq,ueou8 sodium chloride solution were determined. The activity coefficient of the amine in the aqueous sodium chloride solution was calculated (84) from the value of mp/ma and the corresponding value at zero molality, taking zero molality as the standard state, when by definition f=l, and taking the activity coefficient of the amine, in the organic phase, equal to unity. The salting coefficient(44d) was obtained from the best linear relation of log fAme VS. the sum of the amine and sodium chloride concentrations, in the aqueous phase. This linearity is in concordance with the findines of Randall and Faile7(71, • |