Systems of Four Immiscible Liquid Layers

Abstract

SYSTEMS of three immiscible layers are sufficiently uncommon to be noteworthy, and no system of four layers appears to have been described (excluding systems containing free mercury). Nor is this remarkable when it is recalled, first, that practically all dry organic liquids are completely miscible, almost the only exceptions being polyhydric alcohols; secondly, that a system of four liquid phases requires the existence of four substances or solutions, which taken three at a time yield at a fixed temperature four systems each of three liquid phases, the immiscibility of which is in no case destroyed on saturation with the fourth component. The majority of the hitherto-described systems of three liquid phases (of which the system water-aniline-hexane is typical) owe their existence to the properties of a substance such as aniline or succinic nitrile, which is not completely miscible with water, but itself absorbs sufficient water to destroy its miscibility with another solvent, such as hexane or carbon disulphide, which absorbs only traces of water.