Kenneth J. James, Ph.D.,* Supercritical Fluid Technologies, Inc., David Chesney, Ph.D., Michigan Technology University, Jennifer L. Lefler, GlaxoSmithKline
Abstract
Direct, visual observation of materials under supercritical conditions is an important first step in the development and refinement of supercritical fluid extraction, reaction, and chromatographic processes. A specially designed phase equilibrium view cell or “Phase Monitor” is used to observe the dissolution, melting, precipitation, swelling and crystallization of compounds at a wide range of pressures and temperatures. Observations of materials are performed in the supercritical region, under precisely controlled conditions. The Phase Monitor simplifies the determination of critical point for binary, tertiary or complex mixtures. Through a better understanding of phase behavior as a function of temperature, pressure, and sample concentration, a significant time and cost savings for supercritical process development is realized. Examples of the Phase Monitor’s utility are presented.