Magnetic gold nanocatalyst (nanocat-Fe-Au): catalytic applications for the oxidative esterification and hydrogen transfer reactionsElectronic supplementary information (ESI) available. See DOI: 10.1039/c4gc00774c

• Main Authors: Gawande, Manoj B, Rathi, Anuj K, Tucek, Jiri, Safarova, Klara, Bundaleski, Nenad, Teodoro, Orlando M. N. D, Kvitek, Libor, Varma, Rajender S, Zboril, Radek
• Format: Article
• Language: English
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/c4gc00774c

An efficient and sustainable protocol is described for the oxidative esterification of aldehydes and the reduction of aromatic nitro compounds that uses a magnetically separable and reusable maghemite-supported gold nanocatalyst (nanocat-Fe-Au) under mild conditions. The complex chemical, morphological, structural and size analyses, including e.g. XPS, HRTEM, in-field Mössbauer spectroscopy and HRTEM, revealed that the hybrid material is composed of a well-defined stoichiometric maghemite support (20-30 nm) decorated with ultrasmall (5-6 nm) gold nanoparticles. The hybrid catalytic system containing 4 wt% of nanogold has been generated using simple impregnation methods in aqueous medium from readily available starting materials and was recycled five times without any significant loss in catalytic activity; high yields, 40-95% and 83-94% for oxidative esterification and reduction reactions, respectively, were obtained. Maghemite-supported gold (nanocat-Fe-Au) nanocatalyst enables the oxidative esterification of aldehydes and reduction of aromatic nitro compounds in benign medium.