Cobalt nanoparticles as recyclable catalyst for aerobic oxidation of alcohols in liquid phase
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Cobalt nanoparticles prepared at room temperature from cobalt sulphate and tetrabutyl ammonium bromide as surfactant have been found to be effective oxidation catalysts. Palladium and platinum nanoparticles (average size 4–6 nm) can also be prepared from PdCl2 and K2PtCl4, respectively, using the same surfactant but require high temperature (~120 °C) and much longer preparation time. Agglomeration of nanoparticles prepared from metals like palladium and platinum in common solvents, however, restricts their use as catalysts. It is therefore our endeavour to find the right combination of catalyst and solvent that will be beneficial from industrial point of view. Magnetic property measurement of cobalt nanoclusters was made using SQUID to identify their reusability nature. Herein, we report the use of cobalt nanoparticles (average size 90–95 nm) in dichloromethane solvent as effective reusable catalysts for aerobic oxidation of a variety of alcohols.
KeywordsCobalt Nanoparticles Oxidation Agglomeration Recyclability Magnetic properties
The authors are grateful to the University Grants Commission, New Delhi for providing financial support and scholarship to A.M. The authors are also grateful to Dr Sudipta Bandyopadhyay of CRNN for providing us the facility of SQUID and to Dr Nikhil Ranjan Jana, Scientist, Indian Association for Cultivation of Science, Jadavpur, for XPS studies.
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