The Application Of Supported Nano-Catalysts In Oxidation Reactions Involving Alcohols

With the development and progress of nanotechnology and green synthetic chemistry, supported metal nano-catalysts have received more and more attention in both academia and industry.This thesis mainly studies on the preparation methods and catalytic performance of different metal nano-catalysts supported on various templates.The first part is about the preparation of palladium nanoparticles supported on DNA and the application of this catalyst in dehydrogenation oxidation of alcohols for selective synthesis of imines. Through screening the catalysts, we find that the catalyst of palladium nanoparticles supported on DNA has excellent chemoselectivity and catalytic activity in the reaction of alcohols and amines. This reaction can afford imines in high yield via oxidation of the alcohols with the liberation of hydrogen. By virtue of the liberated molecular hydrogen, the nitroarenes could also be deoxidized in situ into amines and an one-pot tandem synthesis of imines is achieved from nitroarenes with alcohols. The second part is about the preparation of platinum, palladium and gold nanoparticles supported on hybrid of MMT and DNA and the application of these catalysts in selective aerobic oxidation of alcohols. Through optimizing the reaction conditions, we can know that these as-synthesized catalysts can transform the primary alcohols into the corresponding aldehydes, acids and esters. The third part mainly studies on the application of gold nanoparticles supported on DNA for the synthesis of amides. We design that the reaction of alcohols with azides can give the product of amides through the processes of hydrogen-transfer and aerobic oxidation successively. We find that the processes of hydrogen-transfer and aerobic oxidation of alcohols can be promoted mutual from the reaction mechanism. The fourth part mainly studies on the application of gold nanoparticles supported on titanium dioxide in the reaction of alcohols with nitrocompounds, in which the starting materials can be converted to desired benzoxazoles and benzimidazoles via two hydrogen-transfer processes. Depending on these catalytic systems, the catalyst can be reused for7times at least, and the yield of the product is not decreased. As for noble metal of gold catalyst, these results show that this catalyst has a promising prospect in industrial application. The last part is mainly about the application of gold nanoparticles supported on titanium dioxide for the synthesis of quinazolines. During optimization of the reaction conditions, an alkaline nitrogen source can promote the reaction, but an acidic nitrogen source was unfavorable to the reaction. The acidic nitrogen source can destroy the catalyst by characterization means, which lead to the loss of catalytic activity. Similarly, the catalyst could be reused at least8times without loss of its activity.In conclusion, the as-prepared catalysts are successfully applied in various cascade oxidation reaction involving alcohols through adjusting the template and metal of the catalyst, which can give us the desired products. The reaction shows excellent selectivity, activity and recycling of the catalyst, and good tolerance to air and moisture.