Preparation Of Vanadium-based Nitrogen-doped Carbon Material And Catalytic Oxidation Of Alcohols

Carbon-carbon?C-C?bonds and carbon-hydrogen?C-H?bonds are the basic chemical bonds in organic molecules.The oxidative cleavage reaction of C-C and C-H is an important synthetic method for introducing oxygen-containing functional groups such as carbonyl groups into organic chemistry.Conventional methods are achieved with stoichiometric or even excessive amounts of strong oxidants,while inexpensive non-precious metal heterogeneous catalysts are reported relatively few.Vanadium is a kind of rich element and it has the advantages of being cheap and easy to obtain,meanwhile it is widely used in the field of catalytic oxidation.Vanadium-based nitrogen-doped carbon materials?V-N-C?can enhance their electrical conductivity and electron transport ability due to the introduction of nitrogen atoms.The chemical environment around them will change after the incorporation of metal components,and electron transfer will occur between the metal and the carrier.Factors contribute to some of the singular catalytic properties of metal nitrogen-doped carbon materials.In this dissertation,V-N-C was synthesized and its structure was characterized.The research first time used V-N-C as a catalyst and oxygen as a green oxidant by C-C bond oxidative cleavage and carbon-hydrogen bond oxidation to introduced into the carbonyl group.The main research contents of this thesis are as follows:Synthesis and catalytic oxidation of V-N-C for lactone:melamine is small molecular organic nitrogen source,ammonium metavanadate is metal vanadium source,and V-N-C is synthesized.Then lactone was prepared by catalytic oxidation of cyclohexanol as a model reaction to investigate the catalytic C-C bond oxidative cleavage of V-N-C catalyst.By investigating the catalytic activity of different calcination temperatures on V-N-C catalysts,it was found that the calcination temperature of 500°C had a good catalytic activity for the catalytic oxidation of cyclohexanol to lactone.The reaction conditions were optimized.The preferred reaction conditions were as follows:reaction temperature is 120°C,reaction time is 8h,reaction pressure is 0.5 MPa O₂,solvent is acetonitrile,the conversion of cyclohexanol is89%,and the selectivity of lactone is 60%.Catalytic Oxidation of Methyl Pyruvate with V-N-C:Using V-N-C with Calcination temperature of 700°C as catalyst and catalytic oxidation of methyl pyruvate with methyl lactate as a model to explore V-N-C catalyst catalytic performance of C-H bond oxidation.The results showed that the reaction rate of methyl lactate was 99%and the selectivity of methyl pyruvate was 95%at 120°C,0.5 MPa O₂,5 wt.%V-N-C and acetonitrile as solvent.This dissertation realizes the new application of V-N-C in the field of catalytic oxidation,and provides new ideas for the catalytic oxidation of C-C bonds and C-H bonds by molecular oxygen,which provides a reference for the development of green catalytic oxidation technology and has an important application background.