Studies in Triethylamine-Water. Part--IV : Predicting the Solubilities of Triethylamine and Water

Department of Chemistry, Loyola College, Madras-600 034 Manuscript received 27 January 1982, accepted 7 June 1982 The solubility curve of the binary system triethylamine-water, which has a lower critical solution temperature of 18.3°, is predicted from simple thermodynamics by analysing the vapour pressure data. In this method, the equation for gE (the molar excess free energy of mixing) of amine-water systems is assumed to hold good for temperatures at which the system is only partially miscible. The common tangential points on the curves of gM (the molar free energy of mixing) vs X (the solvent compo­sition, expressed in mole fraction of Et2N in water), drawn as isotherms, reproduce the experimental volubility curve of the binary system within ±2 per cent