Synthesis of fullerenes: An effort to optimize process parameters Original Research Article

Fullerenes in yields as high as 15 wt% have been synthesized in a flow through reactor assembly employing the contact arc method. The yields are found to be greatly affected by arcing parameters like the flow rate of helium and current. UV radiation emitted during arcing was found to reduce fullerene yields. Steps to minimize UV scattering and decrease the residence time of the carbon vapor resulted in higher yields. This work involves the study of such factors that could provide insight into design aspects in an effort to maximize fullerene formation. The separation of C60 and C70 fullerenes by column chromatography was also investigated. The preadsorption technique utilizing solvents such as carbon disulfide, carbon tetrachloride, and cyclohexane on a n-alumina stationary phase has shown to result in a faster separation of the two fullerene fractions. The purity of the fractions were tested using UV/Vis spectrophotometry which revealed no contamination due to the preadsorption solvent.