Equilibrium study on reactive extraction of propionic acid with N1923 in different diluents

Abstract: The equilibrium for the propionic acid extraction by N1923 in three diluents, represented as proton-donator (n-octanol), polar (butyl acetate), inert (hexane) types, have been studied. The diluents had a significant influence on the equilibrium. The loading ratio, Z, was employed to investigate the effect of diluents on the extraction efficiency. When Z exp was lower than 1, N1923 extraction followed the order: n-octanol>butyl acetate>hexane. When the loading ratio Z exp was higher than 1, the order changed to: butyl acetate>hexane>n-octanol. Equilibrium complex constants K 11, K 21, K 31 have been estimated. The results showed that K 11 was much higher than K 21 and K 31, demonstrated K 11 as the dominant factor in the extraction process. Comparing the values of K 11 of all the three diluents, the following order was observed: n-octanol>butyl acetate>hexane. The influence of amine concentration on the extraction equilibrium constant in different diluents was also investigated. The extraction equilibrium constant K 11 decreased with the increase of amine concentration in n-octanol. When hexane and butyl acetate were used as diluent, the extraction equilibrium constant K 11 increased slightly with the increase of amine concentration. [Copyright &y& Elsevier]