Nanosized Copper Supported on Graphene as Catalyst for the Oxidative C-O Cross-Coupling of Phenols

Abstract

Copper nanoparticles prepared by the polyol reduction method have been supported on graphene and the resulting Cu/G catalyst used for the oxidative C−O cross-coupling of o-substituted phenols and N,N-dialkylformamide to the corresponding carbamates. The presence of B or N dopant elements on graphene plays a negative effect on the catalytic activity of resulting Cu supported catalyst. The advantage of using graphene as support is illustrated by the superior catalytic activity of Cu/G compared to Cu supported on single walled carbon nanotubes, diamond nanoparticles, active carbons and acid (TiO2 and CeO2), neutral (Al2O3) and basic (MgO) metal oxides. Cu/G catalyst was recovered and reused without observing variations in the time-conversion plots of the reaction. Moreover, the catalyst is also efficient for the coupling of ethers and aldehydes. The scope of Cu/G as catalyst for the oxidative C−O coupling includes other related aromatic and non-aromatic compounds.