Nanoshell carbon-supported cobalt catalyst for the aerobic oxidation of alcohols in the presence of benzaldehyde: An efficient, solvent free protocol

A versatile, solvent free aerobic alcohol oxidation system has been established in the presence of benzaldehyde based on a heterogenous cobalt catalyst supported on nanoshell carbon (Co/NSC), which was prepared through the pyrolysis of a mixture of Co(II) phthalocyanine and phenol resin. The established system features equal efficiency toward both benzylic alcohols and aliphatic alcohols. The nanoshell carbon has been demonstrated to be a better supporting material for the present reaction than some other carbon materials, e.g., activated carbon. Mechanistic studies suggest that Co/NSC can catalyze the formation of oxidative intermediate peroxybenzoic acid as efficiently as homogeneous cobalt catalyst, and moreover, suppress the undesired Baeyer–Villiger side reaction. Co/NSC also exhibits good reusability, i.e., it can be reused for at least 10 times without significant loss of performance.

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► The system oxidizes aliphatic alcohols as efficiently as benzylic alcohols.
► Oxidation reactions are carried out under solvent free conditions.
► Nanoshell carbon with cobalt nano-particles supported is a highly stable and easily recoverable heterogeneous catalyst.
► Cobalt particles hidden in the bulk of carbon are also accessible for reactions.