Preparation Of Silver Nanoparticles And Its Catalyzed The Selective Oxidation Reaction Of Alcohols/Aldehydes

Oxidation is one of the important ways for the transformation between different substances.Wherein,the selective oxidation of alcohols or aldehydes is the common reaction in chemical industry,and have attracted much attention.Most of the conventional oxidation methods usually require stoichiometric amounts of metal oxidants,which are expensive and caustic.Meanwhile,some toxic reagents have to use as the solvents which is harmful to environment.Recently,with the development of green chemistry,to seek more moderate catalytic oxidation system has become a hot spot in the current research.In this thesis,silver nanoparticles were prepared by liquid phase reduction and silver nanoparticles loaded by g-C₃N₄ were synthesized by a facile impregnation-roasting method.Then,the two kinds of silver nanoparticles were characterized by HRTEM,XRD,etc.The results showed that the silver nanoparticles were uniform with 30-40 nm particle size.The selective catalytic oxidations of alcohols/aldehydes were carried out by using the two kinds of silver nanoparticles as catalysts,respectively.By adjusting reaction conditions,the selective oxidation of alcohols and aldehydes were achieved respectively with silver nanoparticles as the catalyst and oxygen as the oxidant.The main research works of this thesis are as the following:?1?The selective oxidation of alcohols catalyzed by Ag/g-C₃N₄ in THF solvent under visible light irradiationThe oxidation of alcohols was catalyzed by silver nanoparticles in THF solvent with molecular oxygen as the oxidant under visible light irradiation.Different from the method reported in the literature,the reaction can be carried out without high pressure and noble metal catalyst.Furthermore,the catalytic system was more highly efficient for benzyl alcohols.?2?Silver nanoparticles catalyzed the selective oxidation of aldehydes in waterThe oxidation of aldehydes was achieved in water by using silver nanoparticles as the catalyst and Na OH as base under mild conditions.The reaction tolerance of aromatic aldehydes substrates is very good.In addition,green solvent-water was used in the system without expensive additives or ligands.Further more,it can be also suitable for the gram-scale reactions.