Study On Catalytic Performance Of The N-Containing Porous Carbon And Zeolite Materials For The C-N Bond Formation Reaction

In the organic synthesis reaction,homogeneous catalysis has always played an important role in the preparation of functional compounds and high value-added chemicals.However,to achieve the purpose of the high yield of the target product,it is inevitable to add various additives into the reaction system,such as,acids,bases,metal-organic ligands,etc..This not only makes the reaction system more complicated,but the catalyst has the difficulty to be separated and recycled,which limit the practical application in industry.Among various catalysts,heterogeneous catalysts have the inherent advantages of easy separation,recyclability and environmental friendliness,and show good catalytic properties in various organic reactions.In view of this,three kinds of heterogeneous catalysts with different properties were developed for the synthesis of C-N bonds containing compounds.In this paper,the catalytic performance of nitrogen-doped porous carbon（NC）materials and zeolite-assembled transition metals in the C-N bond forming reactions was investigated.It was found that the prepared heterogeneous catalysts have obvious advantages:First,the nitrogen-doped porous carbon（NC）and zeolite materials have a unique chemical environment,which can coordinate with metals to modify the electronic and spatial structure of metals,accompanying with the stabilization of metal sites;Second,the catalyst has good stability and recyclability.The detailed studies are as follows:1:Cobalt-nitrogen co-doped porous carbon materials realize ammoxidation of aromatic aldehydes with ammonium carbonate:Cobalt-nitrogen co-doped porous carbon catalyst（Co@NC-T）was prepared by a hard template-high temperature pyrolysis method using natural vitamin B₁₂as the carbon source（T is the pyrolysis temperature）.Compared with Co@NC-700,Co@NC-600 and Co@NC-500 catalysts,Co@NC-800exhibited good activity and selectivity in the ammoxidation of aromatic aldehydes with ammonium carbonate.The excellent catalytic performance of Co@NC-800 may be due to the presence of highly dispersed Co species with lower electron density,which can interact with the benzene ring in the p-πconjugated benzaldehyde-containing molecule,thereby promoting the adsorption of benzaldehyde and activation.The activated benzaldehyde reacts with the amino group decomposed by ammonium carbonate,and then undergoes a dehydration process to generate nitrile.2 Zeolite-assembled metal molybdenum-catalyzed dehydrogenation coupling reaction of benzyl alcohol and o-phenylenediamine:mesoporous Silicalite-1 zeolite-assembled Mo（Mo/Silicalite-1-M）catalyst was prepared,which is green and efficient catalysis the dehydrogenation coupling of benzyl alcohol and o-phenylenediamine.Compared with the mesoporous zeolites（TS-1,ETS-10,ZSM-5）supported Mo catalyst,Mo/Silicalite-1-M catalyst exhibits good activity and selectivity in the dehydrogenation coupling reaction.The excellent catalytic performance of Mo/Silicalite-1-M may be due to the synergy effect of Mo species and Silicalite-1-M zeolite.After repeated use for 5 times,the Mo/Silicalite-1-M still show high activity and selectivity.3 Nitrogen-doped carbon materials（NC）catalyzed the reaction of benzyl alcohol and benzonitrile to synthesize N-benzylbenzamide:Nitrogen-doped carbon materials were synthesized from o-phenylenediamine（NC-T）（T is the pyrolysis temperature）,and the effect of pyrolysis temperature on the reaction performance was studied.Compared with Co@NC-800,and NC-T（T=600,700,800°C）catalysts,NC-800 exhibited good activity and selectivity in the synthesis of amides from benzyl alcohol and benzonitrile.This method has the superior advantages of easy recovery,simple reaction and no harmful by-products to that of the conventional method.This strategy broadens more possibilities for the amide synthesis.