Synthesis of gram quantities of C60 by plasma discharge in a modified round-bottomed flask. Key parameters for yield optimization and purification. Technical report

Described is the fabrication of a plasma discharge reactor constructed from a 1 L round-bottomed flask that allows for the preparation of gram-quantities Of C60 in an eight hour period. The modified reactor design (1) is inexpensive (2) requires almost no machining (3) has high thru-put (4) affords high yields of fullerenes (5) allows one to have near continuous feed of graphite rods and (6) permits control over four major reaction parameters important for the clean formation of fullerenes. The four major reaction parameters necessary to control for the high yield of fullerenes are the absolute pressure, the rate of helium gas flow through the reactor, the current level of the arc as determined by the setting on the arc welding unit, and the arc gap maintained by monitoring the current on a clip-on digital AC current meter. Since the apparatus described can allow for easy adjustment of all four major reaction parameters, this design could also be used to study the changes in fulleroid content based on parameter modification. Also detailed is the efficacy of a procedure for the purification of the crude fullerene mixtures using activated charcoal as a chromatographic stationary phase.