Journal of Chemical and Engineering Data, Vol.39, No.3, 506-509, 1994
Vapor-Liquid-Equilibria and Salt Apparent Molar Volumes of the Water Plus 2-Propanol Plus Tetrabutylammonium Bromide System
Vapor-liquid equilibrium and density measurements have been performed on 1.00-5.89 m tetrabutylammonium bromide (TBAB) in mixtures of 2-propanol and water. The VLE experiments were performed using a modified Othmer still at ambient pressure. The effect of salt on the relative volatility of 2-propanol was evaluated at molalities of 1.00, 1.79, and 5.89 over the full range of solvent composition. At each salt molality, as the alcohol concentration increased, salting-in and then salting-out behavior of the alcohol was observed. The azeotrope was shifted but apparently not eliminated for the salt concentrations studied. Density measurements at 25, 40, and 55-degrees-C were taken using a vibrating tube densimeter at four salt molalities over the full range of solvent composition. As salt molality increases, the apparent molar volume of TBAB exhibits a minimum between 1 to 2 m TBAB in pure water, it is slightly larger and monotonically increases in pure 2-propanol, and it is larger yet, with a maximum at lower 2-propanol amounts, in the ternary mixture.
Keywords:SATURATION