Hydration of N, N-bis(2-ethylhexyl)hexanamide in dodecane

The hydration and dimerization of N, N-bis(2-ethylhexyl) hexanamide (BEHHA) in dodecane were studied on the basis of the water distribution between aqueous solutions and dodecane. The data obtained at 298 K were analyzed as functions of the amide concentration in the organic phase and the water activity in the aqueous phase. When the amide was monomeric in the organic phase, only a monohydrate was formed. At high amide concentrations in the organic phase, dimerization of the monohydrate occurred and (BEHHA)2(H2O)2 was formed. No other dimer hydrates were found in the organic phase. The results were compared with those of tributyl phosphate (TBP). The stoichiometry between BEHHA and water was investigated from low to very high amide concentrations in dodecane. The change in the activity coefficient for an amide contained in an inert solvent at high concentrations was also examined. (author)