| 摘要: | Au is deposited as nanoparticles on metal oxides by means of coprecipitation and deposition-precipitation techniques, it exhibits surprisingly high catalytic activity. The performance of gold catalysts is known to be highly dependent on the combination of two factors: the size of the gold crystallites and the nature of support. It has got various applications and can promote many reactions when stabilized in the form of nanoparticles attached to metal oxides. Research and development on the catalysis of gold has been rapidly growing in the world. Recently, the discovery of gold supported catalysts for the production of substituted anilines has opened up new horizons around the chemistry of nitrogenated compounds. Development of a suitable gold supported catalysts for hydrogenation of nitrostyrene, in which two functional groups present and olefinic bond has to be protected from hydrogenation, will be an efficient and greener substitute for the conventional stoichiometric reducing agents and non-selective Pt, Pd and Ni catalysts. Functionalized anilines are an important intermediate in pharmaceuticals, dyes, agrochemicals, and fine chemical industries. The specific aim of the project proposal is to develop a gold supported catalyst for chemoselective hydrogenation of nitrostyrene with high selectivity towards functionalized anilines and without compromising conversion. It is generally well known that the addition of a metal to oxides can modify the intrinsic catalytic properties of the oxides, possibly increasing the activity, selectivity, or stability of the obtained products. But not all metal oxides can be a promoter, it would decrease the activity sometimes, it called as additive. The role of a beneficial additive may be a chemical promoter, a structural promoter, or a cocatalyst. A chemical promoter implies that the additive, though not active itself, improves the effectiveness of the catalyst by chemical means. A structural promoter increases the catalytic activity by modifying the structure of catalyst, and a cocatalyst has an active role in the catalytic action and acts along with the main catalyst. In general, mixed metal oxide supports proved to improve the catalytic activity of gold catalysts, and increase selectivity and conversion of a number of reactions. Hence, in this proposal, different reducible and inert supports will be used to prepare gold nanoparticles supported on mixed metal oxides to study the promoting effects of cocatalyst on selectivity and conversion. |
