The Preparation Of Non-nobel Metals Supported By ZIFs-derived Carbon Materials And Their Application In The Synthesis Of Aromatic Amines

Zeolitic imidazolate frameworks（ZIFs）has unique porous structure,adjustable pore size and large specific surface area.The N-doped carbon materials derived by ZIFs can maintain the inherent characteristics of ZIFs such as high N content,large specific surface area and porous structure to a certain extent.ZIFs-derived M@NCs have the advantages of cheap,low toxicity and easy product separation,and thus have a wide range of application prospects.Aromatic amine compounds are widely used in chemistry,biology,medicine,materials,energy and environment.Therefore,it is great important to synthesize aromatic amine compounds through green and sustainable methods.In this thesis,the ZIFs precursor was modified to prepare Co/N doped carbon materials and Fe single atom/N,S-doped carbon material,and the catalytic performance of those materials in selective reduction of nitroaromatics and the N-alkylation reaction of aromatic amines with alcohols was explored,respectively.The specific research content is as follows:First,the Co-based N-doped carbon materials was synthesized by pyrolysis of Co Zn bimetal ZIFs,and the prepared catalyst was applied to the selective reduction of nitroaromatics.The optimal reaction conditions are as follows:the reaction solvent is ethanol,the reaction time is 6 hours,the reaction temperature is room temperature,the reducing agent is hydrazine hydrate,and the yield of the target product can reach 99%.Through the catalyst recovery test,it is found that the catalyst can be recycled 10 times without significant reduction in catalytic activity.At the same time,the catalyst has good substrate applicability and can be used to prepare complex aniline drugs and intermediates.Second,a green and gram-scale strategy has been developed for the synthesis of Fe single atom/N,S-doped carbon catalyst(Fe₂₀-SA@NSC)via the pyrolysis of polyaniline（PAN）-modified Fe-doped ZIFs,in which the synthesis of ZIFs can be accomplished in water at room temperature.The as-prepared catalyst exhibits superior activity on the N-alkylation of the amines with alcohols via borrowing strategy under solvent-free conditions.The optimal conditions for the reaction are as follows:under Ar atmosphere,the reaction time is 24 hours,the reaction temperature is 135℃,and KOH is added,the yield of the target product can reach 94%.Based on the kinetic experiments and DFT calculations,it is proposed and proved for the first time than the positive charge density of iron site is inversely proportional to the activity of the alkylation reactions under borrowing hydrogen metholody.In addition,this catalyst has wide substrate applicability,and can maintain high catalytic activity even after seven times.