Synthesis Of Metal-Loaded Hierarchically Porous Carbon Catalysts And Their Application In The Synthesis Of N-Heterocyclic Compounds

Owing to the high specific surface area,hierarchically porous structure and excellent chemical stability,hierarchically porous carbon materials are generally utilized in various fields.In this thesis,nitrogen-doped hierarchically porous carbon(NHC)and lignin-derived hierarchically porous carbon(HPClig)are synthesized via the "leavening" method using KHCO3 as pore-forming agent,polymer gel and biomass-derived lignin as carbon source,respectively.Copper supported catalysts Cu/NHC was synthesized using NHC as support and it showed great catalytic activity in the three-component coupling of CO2,n-butylamine and propargyl alcohols to cyclic carbamates.In addition,rhodium phosphide supported catalyst Rh2P/HPClig is synthesized using HPClig as support and it could efficiently catalyze the conversion of ophenylenediamine and acetonitrile to 2-methylbenzimidazole under hydrogen atmosphere.The details are as follows:(1)Cu/NHC is successfully synthesized using NHC as support and the nitrogen-doped mesoporous carbon supported Cu catalyst Cu/NMC is successfully synthesized through direct carbonization as a comparison.Characterizations of two catalysts were investigated by different methods.The two catalysts showed great catalytic activity in the three-component coupling of CO2,n-butylamine and propargyl alcohols to cyclic carbamates.The influence of synthesis conditions and reaction conditions upon the catalytic activity were investigated.The yield of product was up to 99%under the optimized condition.To achieve the same catalytic effect,the Cu loading and catalyst addition of Cu/NHC was quite less than those of Cu/NMC,indicating that hierarchically porous carbon support could provide high dispersion of active species and shorter reactant diffusion distance,resulting in the promoting catalytic activity.Besides,different propargylic alcohols and primary amines are also applicable to the catalytic coupling system for the corresponding oxazolidinone syntheses using 10%Cu/NHC600 and the yield of corresponding products is from 55%to 99%.Furthermore,the 10%Cu/NHC600 shows great catalytic performance after nine-time recycle,demonstrating its great stability.(2)Rh2P/HPClig is synthesized by impregnation using HPClig as support.The catalyst is characterized by different methods.It shows great catalytic activity in the conversion of ophenylenediamine and acetonitrile to 2-methylbenzimidazole under hydrogen atmosphere.The yield of the 2-methylbenzimidazole is up to 92%and the conversion of o-phenylenediamine is 93%under optimized condition(140℃,12 h,0.1 MPa H2).In the reaction,acetonitrile serves as both solvent and reactant.It is a new method for the synthesis of 2-methylbenzimidazole.Moreover,a proposed reaction mechanism is also raised.