Submicron ZnO raspberries as effective catalysts for Fries rearrangement

Abstract

o-Xylene-in-water emulsion droplets have been exploited as soft templates for the synthesis of submicrometer-sized raspberry-like ZnO morphologies. The optical properties, structure and morphology of the microstructures have been characterised by absorption and fluorescence spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and selected area electron diffraction analysis. It has been found that the microstructures could act as an environmentally benign and cost-effective alternative to conventional Lewis acid catalysts for the illustrious Fries rearrangement of o-methylphenyl acetate to 3-methyl-4-hydroxyacetophenone, employed as the model reaction and which has been probed by NMR spectroscopic studies.