Experimental and theoretical study on liquid-liquid equilibrium of 1-butanol+water+NaNO3 at 25 and 35°C

In this work liquid-liquid equilibria (LLE) in the system containing 1-butanol-water-sodium nitrate at temperatures of 25 and 35°C has been investigated experimentally and theoretically. The extended UNIQUAC model has previously been used for correlation of liquid-liquid equilibrium in aqueous salt systems containing alcohols. In that model the excess Gibbs energy consists of two terms, the original UNIQUAC term and Debye-Hückel term which considers the alcohol as a non-electrolyte solute. In this work, a modified extended UNIQUAC model is used by taking into account mixed solvent theories. The model consists of three terms, the original UNIQUAC term, a Pitzer-Debye-Hückel term and a Born term. The model has been found to give a satisfactory description of LLE data obtained in this work, with an average absolute deviation of less than 0.5 in calculated mass percent compared to experimental data