Solution Properties of Dialkyl Phosphate Salts. Apparent Molar Volumes, Viscosity B Coefficients, Heats of Solution, and Osmotic Coefficients

Abstract

The apparent molar volumes, viscosity B coefficients, and heats of solution of sodium salts of dialkyl phosphates (methyl, ethyl, and butyl) in water were measured. The limiting apparent molar volumes at 25 °C increased with the number of carbon atoms in the alkyl chains. The viscosity B coefficients of the salts decreased as the temperature was raised from 25 to 35 °C. The changes in heat capacity for dissolution in water, as calculated from the heats of solution at 15, 25, and 35 °C, were positive for the salts. The osmotic coefficients for lithium, sodium, and potassium salts of dimethyl phosphate were also measured. For a given concentration, the osmotic coefficients decreased in the order: Li+