Submitted to: Intl Symposium on Supercritical Fluid Chromatography and Extraction
Publication Type: Proceedings
Publication Acceptance Date: April 8, 2000
Publication Date: N/A
Technical Abstract: Instrumentation systems incorporating critical fluid technology have been developed to a relatively sophisticated level, ranging from micro-extractors of several milliliters to larger capacity units approaching multi-liter capacity. Analytical supercritical fluid extraction (SFE) systems have not always been designed for such use but can be modified with a modest amount of effort for this purpose. In this presentation, non-analytical applications of the instrumentation for conducting reactions, performing fractionations, evaluating the efficacy of adsorbents and catalysts, and the screening of cosolvents will be documented. A wide variety of reaction chemistries can be evaluated in critical fluid media using analytical extraction equipment. Examples include esterification, transesterification, glycerolysis, and acylation reactions. Flow reactors and batch systems will be described for the synthesis of vitamin E, sterol esters, and specific chiral enantiomers as products. The use of multiple pumping systems and reactors also allows multi-step synthesis of compounds to be demonstrated in supercritical media. Using automated sequential analysers, it is possible to screen for the effect of pressure, temperature, and cosolvent in a combinatorial fashion, thereby reducing the experimental time and effort. Assessment of sorbent selectivity by transforming extraction cells into mini-chromatography columns has been used to optimize enrichment of high value chemicals from natural product matrices. Analogies will be drawn with state-of-the art analytical critical fluid instrumentation and combinatorial approaches currently being used in the pharmaceutical and materials science fields.