Thermodynamic studies of solvent extractions systems—IV: The binary mixtures of tris-2-ethyl hexyl phosphate with benzene, carbon tetrachloride, hexane and chloroform

Abstract

From the total pressures, measured between 25 and 45°C, by the isoteniscope method, the excess thermodynamic functions were evaluated in the tris-2-ethyl hexyl phosphate (TEHP)-C 6H 6, C 6H 14, CCl 4 and CHCl 3 systems. In all cases, negative deviations from Raoult's were observed and the excess free energies of mixing were almost independent of temperature in solutions rich in TEHP (mole fraction of a diluent less than half). Athermal-thermal effects are important for more dilute mixtures. Results in the TEHP-CHCl 3 system, in the 25–45°C range, can be interpreted as due to the formation of AB and AB 2 complexes (A-TEHP, B-CHCl 3) with equilibrium constants K 1 = 9.70 and K 2 = 55.8