Partition data of propionic and butyric acids between aqueous NaCl solutions and cyclohexane

Abstract

The partition of propionic and butyric acids between aqueous NaCl solutions and cyclohexane was carried out at 30°C. Salting out of these acids to the organic phase arises solely from the monomer transfer step. The extent of dimerization of acetic and propionic acids in the aqueous phase was found to be small and independent of salt concentration, while the dimerization of butyric acid increases. The results were analyzed in terms of various aqueous interactions between unlike solute molecules. A simple pair interaction between the acid monomer and salt was identified for all the acid studied. A triplet interaction involving the acid dimer and salt was also identified for butyric acid.