ADSORPTIVE SEPARATIONS USING SUPERCRITICAL FRONTAL ANALYSIS CHROMATOGRAPHY

Many food products and pharmaceuticals industries are looking to integ rating supercritical extraction and separations processes to fulfill p rocessing needs due to limitations and regulations concerning the use of organic solvents. One such technology, which may affect these indus tries, is continuous supercritical adsorptive separation a processing technology similar to the separation process of xylenes developed at U OP. Many products like pharmaceuticals and other human consumables cou ld be processed more economically and with higher purity by supercriti cal fluid adsorption/desorption processes. Past studies, however, have .focused on single-component adsorption/desorption involving a supercr itical mobile phase, whereas adsorptive separations involving supercri tical fluids are multicomponent systems. Accurate experimental techniq ues which can determine both multicomponent solubilities in supercriti cal fluids and multicomponent adsorption isotherms in the presence of supercritical fluids, were developed to investigate the multicomponent supercritical adsorption phenomenon. A dynamic column model developed takes into account column dispersion as well as mass transfer and dif fusive resistances. Experimental isotherm data incorporated into the m odel can predict the breakthrough profiles. An extension of pulse chro matography was used to identify the important hydrodynamic and transpo rt parameters, and operating conditions are identified for optimal sep arations.