Liquid–Liquid–Solid Triple-Phase Data for Aqueous Two-Phase Systems comprising Ethanol–1-Propanol—2-Propanol–Acetone and Salts

Abstract

In this paper, the liquid–liquid–solid triple-phase data of some aqueous two-phase systems (ATPSs) containing hydrophilic organic solvents (HOS) and simple salts were explored. The systems studied comprise aqueous solutions containing ethanol, 1-propanol, 2-propanol, or acetone with (NH4)2SO4 and solutions containing 1-propanol with (NH4)2SO4, NaCl, or KCl. The Gibbs phase rule predicts that there is a linear relationship existing at such a triple-phase boundary. The linear liquid–liquid–solid boundaries were determined, and the effects of temperature, solvent, and salt on the boundary were investigated. The tie line length (TLL) of the systems distributed on the triple-phase boundary was invariant. Phase equilibrium experiments determined that the average TLL of ethanol–(NH4)2SO4 ATPSs at 298.15 K was 62.93 % with a standard deviation of 2.13 %. The linear liquid–liquid–solid triple-phase boundary was used to elucidate the two-phase region and determine the content of organic solvent or salt in an unknown sample. These results increase our understanding of HOS–salt–water aqueous two phase system (ATPS) and will be useful for those looking to develop new systems for separation science.