Abstract
NiAl-hydrotalcite-like-compounds (NiAl HTLcs) with a unique phase and high crystallinity were synthesized utilizing urea hydrolysis. The physicochemical properties of the synthetic samples were characterized by X-ray diffraction, scanning electron microscopy and N2-adsorption- desorption measurements. The catalysed oxidation of benzaldehyde to benzoic acid was performed using dissolved air as oxygen source in acetic acid under the following conditions: 0.1 g catalyst, the ratio V(benzaldehyde)/V(ethanoic acid) was 3/9, with a stirring speed of 800 rev min “1. The heterogeneous NiAl - HTLcs catalysts were recycled several times and showed stable activity without structural change. The reaction mechanism was elucidated via the determination of kinetic parameters. It was shown that the oxidation is of zero order, dominated by classic diffusion. The apparent activation energy was 14.13kJ mol-1.