SOLUBILITY OF FERROCENE AND A NICKEL-COMPLEX IN SUPERCRITICAL FLUIDS

Supercritical fluid extraction of metals in the presence of complexing agents for environmental monitoring, cleanup, and metals processing i s now being extensively researched, and there is a need for solubility data of metal complexes. In this paper, the method used is the combin ation of a study of chromatographic retention over a wide range of pre ssures at 40, 50, 60, and 70 degrees C, followed by selected direct so lubility measurements, to provide a comprehensive set of solubility re sults obtained with minimum effort. The method relies on the assumptio n that an inverse relationship exists between chromatographic retentio n and solubility in the mobile phase. This assumption is checked in th is study. Results are presented for the solubility of ferrocene in sup ercritical carbon dioxide and a nickel complex, (5,7,12,14-tetramethyl -2,3:9, b,i][1,4,8,11]tetraazacyclotetradecine)nickel(II)] in supercri tical carbon dioxide modified with 10 vol % methanol.