Synthesis Of Nitrogen-doped Porous Carbon Materials And Study On Metal-free Catalytic Amine Oxidation

Metal-Free catalysts have widely concerned because they do not contain metals,avoid metal residues and have low cost.Compared with metal catalysts,it shows greener and more environmentally friendly features.Metal-Free catalysts,such as heteroatom-doped carbon catalysts,can be widely used in a series of reactions such as organic synthesis electro catalysis,photocatalysis,biomass conversion and other reactions,due to the adjustable electron and physicochemical structure.Based on this,we carried out relevant experiments,using different preparation methods to synthesize nitrogen-doped metal-free carbon materials,and studied their catalytic performance in selectivity-tunable amine aerobic oxidation and aerobic dehydrogenation of N-heterocycles.The specific research contents are as follows:1.We used SiO₂ as a template agent and Pyrolyze the precursor（11,11’-bis（dipyrido[3,2-a:2,3-c]phenazinyl））to synthesize a series of a series of metal-free N,O-doped carbons catalyst m-NOC-T（T is the calcination temperature）.When oxygen is used as the oxygen source and ammonia water is used as the ammonia source,the formation of the active site of the catalyst is controlled by adjusting the calcination temperature in the early stage to further realize the selective oxidation of the benzyl amines to the corresponding nitrile or imine.The catalyst m-NOC-600 can realize the oxidative coupling of the benzyl amine substrate to generate the corresponding imine,and the catalyst m-NOC-800 can realize the oxidation of the benzyl amine substrate to the corresponding nitrile compound.The catalytic activity of this catalyst（m-NOC-800）has not been significantly reduced after 8 cycles of experiments,and it still maintains excellent catalytic performance.Systematic characterization studies and control experiments revealed that the C–O group on the surface could function as a catalytically active site for nitrile synthesis and the N-doping environment was essential.2.In the previous work,we used organic ligands as precursors and hard template agents as sacrificial agents.In this work,we used simple and easy wheat flour as the precursor,and carried out graded calcination synthesis after alkali treatment.The N-doped hierarchical porous carbon N-HPC-T（T is the calcination temperature）,In the absence of additives,air provides an oxygen source to realize the oxidative dehydrogenation of a variety of nitrogen-containing heterocyclic compounds to synthesize quinolines,isoquinoline,acridine,quinoxaline,indole,imines and even quinoline compounds with pharmaceutical activity.Using 1,2,3,4-tetrahydroquinoline as the model substrate,the reaction conditions were: 110℃,0.2 MPa Air,the substrate conversion rate was 90.2%,and the yield of quinoline was 82.7%.The research results show that the catalytic activity of catalyst N-HPC-800 is comparable to that of metal catalysts.In the follow-up,the wheat flours from six different provinces were compared as catalyst precursors to prepare N-HPC-800 catalyst and tested.The experimental results showed high catalytic activity,further verifying the flour as the universality of catalyst precursors used in the oxidative dehydrogenation of nitrogen heterocyclic.And the catalyst also has many advantages,such as simple preparation method and low cost,and these advantages have laid the foundation for the large-scale industrial production of the catalyst N-HPC-800 in the oxidative dehydrogenation reaction to against nitrogen heterocyclic.