AN EVALUATION OF THE DIFFERENTIAL PARTITIONING AND SEPARATION OF C-60AND C-70 FULLERENES IN A BIPHASIC SYSTEM USING CENTRIFUGAL PARTITION CHROMATOGRAPHY (CPC)

The partition coefficients of C-60 and C-70 fullerenes were measured i n several different organic, 2-phase (liquid-liquid) systems using cen trifugal partition chromatography (CPC). The partition coefficients of C-60 and C-70 were sufficiently different in some biphasic solvent sy stems to provide a CPC separation of these fullerenes. A phase diagram was made of the best 2-phase system for fractionating C-60 and C-70 f ullerenes. This system contained the solvents 1,2-dichlorobenzene, iso octane, and dimethylformamide (DMF). The separation times, selectivity , and efficiency are affected by the ratios of the major solvent compo nents, the addition of small amounts of a quaternary solvent, and the temperature (in addition to the usual instrumental parameters). Prepar ative separations of fullerenes were done and a maximum batch producti on was calculated for one solvent system. It appears that a significan tly greater amount of fullerenes can be purified per run in this syste m than in corresponding HPLC systems. The rather unusual organic bipha sic solvent systems developed for the fractionation of fullerenes may be useful for future separation and purification of more conventional organic compounds.