Experimental Study and Modeling of Vapor–Liquid Equilibria and Excess Molar Volumes in the Di-(2-ethylhexyl)phosphoric acid - Toluene (Cyclohexane, Hexane, Heptane) systems

Abstract

Abstract Saturated vapor pressure of the diluent (toluene, cyclohexane, hexane, heptane) in four binary diluent – di-(2-ethylhexyl)phosphoric (D2EHPA) acid systems was measured by the static method at T = (288.15, 298.15, and 308.15) K in a wide concentration range. Experimental data obtained were correlated with UNIQUAC thermodynamic model taking into account the existence of D2EHPA in the liquid phase in the form of a dimer. Excess molar volumes were determined for binary solutions of D2EHPA with toluene, cyclohexane, heptane in the temperature range of (288.15 – 308.15) K and hexane at (288.15, and 298.15) K using the vibrating tube densimeter. The Redlich – Kister type polynomial equation was applied to describe the volumetric properties of the solutions.