Preparation Of Graphene Based Copper Nanomaterials And Their Catalytic Performance In Coupling Reaction

With the development of green chemistry,people have the higher demands on the catalysts,which promotes more in-depth research of the catalysts.Heterogeneous catalysts,as an important part of the catalysts,possess certain advantages such as easy separation,excellent recyclability and environmental protection,which were widely used in various fields of chemical industry.The application of heterogeneous catalysts into the catalytic system can overcome the product contamination caused by metal residues and prevent the loss of precious metals.In practice,low catalytic activity still exists in heterogeneous catalytic system.And the carrier material has a great influence on the catalytic activity of heterogeneous catalysts.Graphene,as a new two-dimensional carbon nanomaterials with the great physic-chemical properties and huge specific surface area,is an ideal carrier of heterogeneous catalyst.In order to improve the catalytic performance,two kinds of graphene-based copper nano-catalysts with high catalytic activity were designed.The catalysts were utilized as high-efficiency heterogeneous catalysts in the Glaser homo-coupling,and the oxidative coupling of aryl methyl ketones and secondary amines respectively.The main content and result of the study are as follows:1.Stabilized Cu/Cu2O nanoparticles on reduced graphene oxide(Cu/Cu2O-NPs@rGO)was synthesized by the chemical reduction.Cu/Cu2O-NPs@rGO was characterized by XRD,XPS,SEM,TEM and other methods to investigate its microstructure,surface morphology and chemical composition.The heterogeneous catalyst showed excellent catalytic performance for Glaser homo-coupling with O2 as oxidant,EtOH as solvent,Cs2CO3 as base.Especially,the isolated yield of the homo-coupling of phenylacetylene leading to 1,4-diphenyl buta-1,3-diyne was up to 99%.Furthermore,a series of substrates were investigated in the catalytic system such as aromatic and heterocyclic terminal alkynes.And Cu/Cu2O-NPs@rGO showed excellent functional group tolerance.The catalyst can be easily separated and recycled seven times without significant decline in its catalytic performance,which showed excellent recyclability and stability.2.Stabilized Cu2O nanoparticles on reduced graphene oxide(Cu2O-NPs@rGO)catalyst was prepared by facile one-pot hydrothermal reduction method.And the catalyst wascharacterized by XRD,XPS,SEM,SEM-EDS,TEM to study its microstructure,surface morphology and chemical composition.The catalyst shows great catalytic performance in the oxidative coupling of aryl methyl ketones and secondary amines leading to ?-ketoamides,when using O2 as oxidant and N-iodosuccinimide(NIS)as additive under room temperature.Moreover,Cu2O-NPs@rGO exhibited wide universality to the substrates in the synthesis of?-ketoamides.The catalyst also showed great recyclability in recycled experiment.The research showed that graphene could significantly improve the catalytic activity of copper nanoparticles as an ideal carrier,which could promote the research and development of graphene-based metal nanomaterials in the organic catalysis.