Modeling extraction equilibria of butyric acid distributed between water and tri-n-butyl amine/diluent or tri-n-butyl phosphate/diluent system: Extension of the LSER approach

Abstract

Extraction of butyric acid from water by tri-n-butyl amine and tri-n-butyl phosphate dissolved in oxygenated polar diluents of proton-donating and proton-accepting types (1-octanol, acetophenone, ethyl butyrate, ethyl pentanoate, ethyl nonanoate, diethyl malonate), as well as a comparison with extraction equilibria of pure diluent alone have been studied at 298 K. Among the tested diluents, 1-octanol alone yields the highest extraction efficiency. The strength of complex formation is larger for tri-n-butyl amine as compared to tri-n-butyl phosphate both favoring mainly the formation of acid(1)-extractanti structure. Ethyl butyrate promotes more readily the solvation of the formed organic phase complexes.