Preparation And Application Of Environmentally Friendly Biomass-based Supported Metal Catalysts

With the development of science and technology,people's consumption of energy continues to increase.In order to avoid energy shortages,the concept of green sustainable development has attracted more and more attention in recent years.However,the homogeneous catalyst is difficult to recycle,which causes a waste of resources to a certain extent.In the study of heterogeneous catalysts,non-noble metal catalysts such as Cu,Co,Ni,etc.,are relatively abundant and easy to obtain compared to precious metal catalysts such as Pd and Ru,and have a wide range of potential applications in practical applications.Nowadays,under the influence of "green chemistry",more and more researchers are focusing on supported catalysts,which are characterized by easy separation from the product,repeated use,and reduction of metal residues in the product.Combining the previous research foundation of the subject,using chitosan as the carrier of Cu,Ni,Pd and other metals,and chitosan as the nitrogen-containing carbon source,a carbon nanocatalyst with high catalytic activity and cycling ability was prepared.1.Three biomass-supported metal catalysts were prepared by using chitosan as the biomass carrier and Cu,Ni,and Pd as the active metals.By loading three kinds of metals Cu,Ni and Pd on chitosan respectively,they were carbonized in a tube furnace at different temperatures to prepare Cu@CS(300,400,500),Ni@CS(600,700,800)and Pd@CS(600,700,800)carbon nano catalysts.Using IR,TG,SEM,TEM,XRD,EDX,XPS,BET and other characterization methods,the structure and composition of the prepared catalyst were characterized in detail.2.The prepared biomass-supported metal catalyst is applied to the C-H activation/C-S coupling reaction of pyridine amide derivatives,and the optimal experimental conditions are obtained by screening catalysts,oxidants,additives,solvents,temperature and reaction atmosphere.The conditions are: Cu@CS-400 calcined in a tubular furnace at 400 ? as the catalyst,potassium persulfate as the oxidant,silver carbonate as the additive,acetone:water(V:V=1:2)as the solvent,and react at room temperature After 12 h,the product can be obtained in a higher yield.Experiments show that the reaction has a good reaction to sodium benzene sulfinate with electron-withdrawing and electron-donating substituents,and the yield is 45% to 82%.In comparison,due to the influence of steric hindrance,the reaction yield of para-substituted sodium benzenesulfinate is higher than that of ortho-and meta-substituted sodium benzenesulfinate.For the pyridine amide compounds containing electron-donating groups,the corresponding products are obtained in a medium yield,with a yield of 65% to84%.Using isoquinoline instead of pyridine as the guiding group,the sulfonylation reaction can still proceed,and the yield is about moderate.When pyridinenaphthylamine is used as the substrate,the target product is obtained in an excellent yield.However,when the benzene ring contains a strong electron withdrawing group,the reaction cannot proceed.It is found through research that the catalyst has been tested for 5 cycles and found that the heterogeneous catalyst still maintains good activity for the C-S coupling reaction.Through the study of the reaction mechanism,it is believed that the sulfonylation reaction mechanism may be a single electron transfer mechanism,and the possibility Reaction mechanism process.3.The biomass-loaded metal is applied to the Suzuki coupling reaction of the key intermediate bromide of the anti-tumor drug crizotinib and pinacol borate compound.The experimental results show that the reaction conditions of catalyst,alkali,solvent,Screen temperature and atmosphere.The optimal reaction conditions are: Pd@CS-700 as catalyst,potassium carbonate as base,TABA as additive,toluene: water(V:V=1.5:1)as solvent,under nitrogen atmosphere,React at 70 ? for 4 hours.Under optimal conditions,the yield of the target product is 92%.The study found that the catalyst after 6 cycles of experiments found that the Pd@CS-700 catalyst still maintains good activity for Suzuki coupling,and the palladium metal residue is less than 10 nm.Compared with the traditional homogeneous palladium catalyst,the catalyst is expensive and difficulty in metal recovery,heavy metal residues and other issues.