Epoxidation of styrene with hydrogen peroxide using hydrotalcites as heterogeneous catalysts

Several Mg/Al hydrotalcite-like materials with atomic ratios of 2, 3, 4, 6 and 10 were tested as heterogeneous catalysts for the epoxidation reaction of styrene, using a combined oxidant of hydrogen peroxide and acetonitrile in the presence of acetone and water as solvents. Several factors such as the Mg/Al ratio, the presence of the pure hydrotalcite phase in the samples, the reconstruction rate of the hydrotalcite-like phase, carried out during the reaction, and the addition of water, play an important role in the selective epoxidation of styrene. Several characterization techniques such as inductivity coupled plasma (ICP), powder XRD, TGA, IR spectra, SEM, Al-27 NMR spectra, TPD of CO2 and N-2 physisorption were performed in order to correlate the chemical and textural properties of the as-synthesized and calcined materials with their catalytic behaviors. (C) 2004 Elsevier B.V. All rights reserved.