Antioxidant Effect of C60 and C70 Fullerene in the Autoxidation of Ethyl Oleate

The antioxidant properties of C60 and C70 fullerenes were studied spectrophotometrically in ethyl oleate. It was found that C60 is oxidized to fullerene oxide by scavenging the peroxy radical formed in the allylic position to the double bond of ethyl oleate. The scavenging rate constant of C60 has been measured and found considerably higher than that of C70. Surprisingly, C70 appears considerably less active than C60 in scavenging the ethyl oleate autoxidation.
In ethyl palmitate, a saturated fatty acid ester which does not undergo autoxidation, C60, is stable and is not oxidized even at 70oC for several hours. It is also shown that cyclohexene can be used as a model compound for the study of the mechanism of solvents autoxidation and for the evaluation of the protective effect exerted by C60.