The influence of cation, anion and temperature on the liquid–liquid equilibrium of some pentanols–water system

Liquid–liquid equilibrium (LLE) measurements for aqueous systems containing some pentanols and sodium, or potassium nitrate have been performed experimentally at 25 °C and atmospheric pressure. The pentanols are: 1-pentanol (1P), 2-pentanol (2P), 3-pentanol (3P), 2-methyl-1-butanol (3M1B) and 2-methyl-2-butanol (2M2B). The obtained data have been modeled using an extended UNIQUAC activity coefficient model. The influence of the cation, the anion and the temperature on the liquid–liquid equilibrium, are illustrated by applying the Setschenow equation on the studied systems and on other systems from literature. The results show that the influence of sodium salts is higher than that of potassium salts with the same anion and the same alcohol. On the other hand, the influence of the nitrate and bromide salts is lower than that of chloride salts with the same cation and the same alcohol. Linearity of Setschenow relation indicates that the influence of the given salts on the liquid–liquid equilibrium in the systems under study, are additive. The effect of temperature on the phase behavior is that the mutual solubilities of both liquids, in the presence of salt, decrease with temperature.

► Liquid–liquid equilibrium for aqueous + pentanols + Na, or K nitrate has been performed.
► The data have been modeled using an extended UNIQUAC activity coefficient model.
► Setschenow equation was applied to illustrate the influence of cation, anion and T.
► The influence of the nitrate and bromide salts is lower than that of chloride salts.
► The influence of sodium salts is higher than that of potassium salts.