Preparation Of High Dispersion Metal Materials And Catalytic Synthesis Of Nitrogen-containing Compounds From Biomass

For today's fast-growing human society,due to the shortage of petrochemical resources and the increasing demand for chemicals,human urgently needs a new type of resource to replace petrochemical resources to produce chemicals and liquid fuels.Biomass,as the only organic carbon resource that is renewable,cheap and readily available,is a sustainable resource with considerable potential.Therefore,the conversion of biomass raw materials into fuels and high value-added chemicals is a hot topic in the field of sustainable chemistry.Among them,in a series of compounds synthesized from biomass,most of them are oxygen-containing compounds;in contrast,nitrogencontaining compounds are more widely used in medicine,polymer fibers,dyes,pesticides and other fields.However,there are few studies on the conversion of biomass raw materials to nitrogencontaining compounds.Therefore,it is one of the most important research hotspots in this field to prepare high-value-added nitrogen-containing compounds from biomass as raw materials and construct efficient catalytic conversion systems.The purpose of this thesis is to prepare a highly dispersed metal catalyst that selectively catalyzes the conversion of biomass-based compounds into nitrogen-containing compounds.At the same time,it will further construct a reasonable catalytic system,optimize various reaction conditions,and achieve efficient synthesis of biomass-based nitrogen compounds.The main work is as follows:(1)ZIF-67 was prepared by solvothermal method,and was pyrolyzed at high temperature to prepare a highly dispersed metal catalyst Co/N-C.The catalyst was tested by BET,SEM,HRTEM + mapping,XRD,in situ XRD,TGA,XPS and Raman infrared.Co / N-C was used as the catalyst to test its activity in the reductive amination reaction of furfural to N-methyl-furancarboxamide.The reaction conditions such as reaction temperature,reaction time,dosage of catalyst,and solvents were tested.The best reaction conditions are: 0.5 mmol furfural,30 mg catalyst,5 m L tetrahydrofuran,ammonium formate: 1.5 mmol,formamide: 1.5 mmol,reaction temperature is 100 ° C,reaction time is 12 h,The highest N-methyl-furancarboxamide yield is 86%.This catalyst has good stability and can be reused 5 times.Finally,the possibile reaction mechanism was also proposed.(2)In order to further prepare highly dispersed metal catalysts with more dispersed metal sites and better catalytic activity,the introduction of bimetal sites is considered.The bimetallic Co-ZnZIF material was successfully prepared by the solventmal method,and the Co-Zn / N-C material was obtained after pyrolzation.BET,SEM,HRTEM + mapping,TGA,XRD,XPS,TGA were used to study the physicochemical properties and structure of the as-prepared bimetallic catalyst.It was initially applied to the reaction of catalyzing the reductive amination of p-cyanobenzaldehyde to the corresponding nitrogen-containing compound p-cyanobenzyl-N-formamide.48 % yield of pcyanobenzyl-N-formamide could be achieved at 120 ° C,0.5 mmol of p-cyanobenzaldehyde,30 mg catalyst,1.5 mmol formamide,1.5 mmol of ammonium formate,and 5 m L of tetrahydrofuran for 12 h.Futhermore,as-prepared catalyst Co-Zn / NC was used in the reaction for the reduction of nitrobenzene to aniline with formic acid as the hydrogen source,and the reaction temperature,reaction time,amount of formic acid,amount of catalyst,and stirring rate were optimized.The best reaction conditions were obtained at 100 ?,0.2 mmol of nitrobenzene,1.2 mmol of formic acid,2 m L of tetrahydrofuran,and 20 mg of catalyst.After 6 h of reaction,the highest conversion rate of 99% nitrobenzene and 99% aniline yield were obtained.After reuseable study,it was found that the catalyst showed no significant decrease in activity after five cycle.(3)The preparation method of Co-imidazole-sugar based on biomass-based highly-dispersed metal catalyst was discussed,and SEM,HRTEM,XRD,XPS were used to study as-prepared material.It was conducted to the reductive amination reaction of 5-methylfurfural,at 100 ?,0.5 mmol 5-methylfurfural,1.5 mmol ammonium formate,1.5 mmol formamide,30 mg catalyst,5 m L tetrahydrofuran for 12 h,56 % N-(5-methyl-2-furyl)-methyl-formamide yield was obtained.