Recent Developments on Catalytic Applications of Nano-Crystalline Magnesium Oxide

Nanocrystalline metal oxides, MgO, CuO, ZnO, TiO₂ as catalysts or catalyst supports have been received much attention in the recent years, especially nanocrystalline magnesium oxide (NAP-MgO) has been used as a recyclable catalyst for Wittig, Wadsworth–Emmons, aza-Michael, Baylis–Hillman, Strecker, Aldol, Claisen-Schmidt condensation and other useful organic reactions. In general, it is reported that nanocrystalline magnesium oxide shows better activity in many organic reactions. These high reactivities are due to high surface areas combined with unusually reactive morphologies. The nanomaterials were also explored as supports to make supported metal catalysts for the organic reactions. The higher activity of these catalysts was studied partly to understand the mechanism of the reaction, the putative reaction pathways were preliminarily presented with the help of spectroscopic support, XPS, silicon, and phosphorus NMR spectroscopy. The catalysts are recovered and reused for several cycles. These catalytic systems are expected to contribute to the development of benign chemical processes.