Phase comparison technique for measuring liquid-liquid phase equilibrium

In this article, a new method is demonstrated to measure the liquid-liquid phase equilibrium for binary systems. A phase comparison technique was empl oyed to real-time display the phase-time curve in a "wave form (time) objec t'' of Hewlett-Packard visual engineering environment. It was found that th e phase-time curve showed a distorted wave form when liquid-liquid phase tr ansition took place. The abnormal curve can therefore be used to detect liq uid-liquid phase transitions. Measurements were performed in several binary systems such as nitromethane+1-hexanol, nitromethane+butanol, and nitroeth ane+n-hexane. The experimental results are in good agreement with those in the literature. (C) 1999 American Institute of Physics. [S0034-6748(99)0420 4-5].