Isopiestic Determination of the Osmotic and Activity Coefficients of Aqueous Solutions of Symmetrical and Unsymmetrical Quaternary Ammonium Bromides at T = (283.15 and 288.15) K

Abstract

Osmotic coefficients of aqueous solutions of Bu4NBr, sec-Bu4NBr, iso-Bu4NBr, Bu2Et2NBr, and Bu3EtNBr are measured at T = (283.15 and 288.15) K by the isopiestic method. A branched isopiestic apparatus was used. The osmotic data of the solutions were compared at T = (283.15 and 298.15) K. Osmotic coefficient data are correlated using the Pitzer model. The parameters obtained with the Pitzer model are used to calculate the mean molal activity coefficients. Vapor pressures of the solutions are evaluated from osmotic coefficients, and their depression was used for qualitative deduction of solute−solvent interactions occurring in these solutions.