Composites formed by carbon over magnetite were synthesized by impregnating iron oxide with glycerine. The formation of onion-like carbon was found, presenting concentric turbostratic shells with inter-planar spacing of approximately 0.32 nm. The composite presented spherical iron oxide particles with magnetic and amphiphilic properties, which is interesting for use as a catalyst in the petrochemical industry. The magnetic composite presented a high catalytic activity for oxidation of quinoline in the aqueous and mainly in the organic medium. (C) 2012 Elsevier Ltd. All rights reserved.