Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2006.138.143C. RoyBhupesh M. J. Alam M. Goto 1200661Liquid-liquid extraction based on reversible chemical complexation is an efficient separation technique that is highly effective and selective for separating polar organic acids (monocarboxylic acids) from their aqueous medium. Extraction equilibria of aqueous solutions of monocarboxylic acids such as acetic acid, propionic acid and butyric acid with Tri-n-butyl phosphate (TBP) in dodecane were measured at the temperature (20±1)°C under various concentrations of acids, extractant (TBP) and also with the variation of organic/aqueous phase ratio. An expression for the extraction equilibrium was derived by which the extraction equilibrium constant (Kc) as well as the number of apparent reacting molecules of extractant (n) were evaluated. From the experimental data it was observed that the estimated values of extraction equilibrium constant (Kc) and the apparent number of extractant molecules reacting with one molecule of each acid dependent on the organic phase composition as well as on the concentration of aqueous phase, due to which each acid gave different extraction isotherms.]]>King, C.J.,19931993pp: 1771062Tamada, J.A., A.S. Kertes and C.J. King,19902913191326Eyal, A.M. and R. Canari,19953417891798Kertes, A.S. and C.J. King,198628269282Cai, W., S. Zhu and X. Piao,20014614721475Hano, T., M. Matsumoto, T. Ohtake, S. Kiyotaka, H. Fumiaki and K. yoshinobo,199023734734Spala, E.E. and N.L. Richer,198221409415Wang, D. and H. Li,19931993pp: 1103pp: 1103