EFFECT OF MAGNESIUM-CHLORIDE ON THE ISOBARIC VAPOR-LIQUID-EQUILIBRIA OF FORMIC ACID-WATER SYSTEM

Formic acid and water form a maximum-boiling azeotrope in their mixtur es. To break the azeotropic boiling in this system, inorganic salts ar e frequently added, because the addition of electrolytes alters signif icantly the equilibrium nature of the original system. In this paper w e report the vapor-liquid equilibrium data for the formic acid-water-m agnesium chloride system over a wide range of salt concentrations at 7 60 mmHg. On the pseudo-binary assumption the equilibrium data were cor related with Hala's model for liquid phase, by considering the chemica l equilibrium in vapor phase. The model showed an excellent agreement with experimental data over a broad range of salt concentrations. (C) 1998 Elsevier Science B.V. All rights reserved.