Influence of salt concentration on solubility and tie-line data for the system: Formic acid + n-butanol + water

ABSTRACT

The tie-line and solubility data, i.e. formic acid (FA) + n-butanol + water + NaCl, were resolved at T = 298.15 K and under ambient pressure. The Othmer–Tobias equation was applied in this study. The experimental data were correlated and all linear correlation coefficients were found to be approximately equal to 1. Both the Universal Quasi-chemical Theory (UNIQUAC) and Nonrandom Two Liquid Theory (NRTL) and NRTL models were employed in order to compare the experimental liquid–liquid equilibrium (LLE) and tie-line data. Consequently, the calculated and experimental data proved to be a good fit. Results show that adding salt to the system proved beneficial by increasing the separation of FA from water.

KEYWORDS:

• Salt effect
• LLE
• separation
• NRTL
• UNIQUAC

Acknowledgments

The authors wish to thank the Rachadapisek Sompote Fund for Postdoctoral Fellowship, Chulalongkorn University. Sincere thanks are also given to the Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University and the Department of Organic Technology, Slovak University of Technology, Bratislava, Slovakia.