Regioselective oxidation of n-hexane and aromatics in the presence of cyclodextrins during H 2O 2 fuel cell reactions

Abstract

The partial oxidations of n-hexane and aromatic hydrocarbons have been carried out at room temperature during H 2O 2 fuel cell reactions. The FeCl 3-embedded graphite was the most active cathode for the partial oxidation of n-hexane α- and β-cyclodextrins added to this cathode improved appreciably the regioselective oxidation of terminal methyl groups due to the inclusion of n-hexane in the cavities of cyclodextrins. However, α-, β-, and γ-cyclodextrins did not exert any regioselective effect on the hydroxylation of toluene, ethylbenzene and naphthalene. Addition of cyclodextrins and D-glucose, in general, increased the current, enhanced the rate of hydroxylation of aromatic rings, and decreased the rate of side chain oxidation, consequently increased the selectivity to phenolic products. These favorable effects of additives have been ascribed to the increase in the concentration of Fe 2+ effective to the reaction.