生物质基糠醛化学催化制备含氮化合物的研究进展

Research progress of chemical catalysis for biomass-based furfural to nitrogen-containing compounds

糠醛作为最有潜力的生物质基平台化合物之一,可通过化学催化转化为一系列高附加值的化学品和燃料。其中,含氮化合物具有广泛的生物活性,常用于合成药物分子和生物塑料等功能性材料。糠醛通过还原胺化、氨氧化、氧化偶联等过程,可以合成不同类型的含氮化合物,具有巨大的研究前景和应用潜力。本论文综述了近年来以糠醛为原料合成各种高值含氮化合物的研究进展,包括胺类化合物(伯胺、仲胺和叔胺)、腈类化合物、酰胺类化合物和杂环类化合物(苯并杂环类、噻唑类、吡咯、吲哚、哌啶和吡啶等)。重点关注合成方法、催化剂类型、反应路径和反应机理,同时分析了催化剂和氮源对产物分布的影响。该综述为今后生物质基糠醛转化为含氮化合物的研究提供了一些基础信息,为发展更多高效的糠醛催化转化体系提供依据和系统性知识。

The utilization of biomass holds a great promise to partially replace the non-renewable fossil resources for the production of chemicals and materials for daily use,which could effectively mitigate the challenges associated with global resource scarcity.Furfural,a prominent biomass-derived platform compound derived from the dehydration of xylose in hemicellulose,which is widely used as the key intermediate or solvent in the petrochemicals,coating,pesticides,medicine,synthetic rubber,etc.At the same time,furfural can be converted into a series of high value-added chemicals and fuel,such as alcohols,acids,esters,nitriles,amines,and others due to its active C=O bonds and furan rings.Typical chemical reactions,such as reduction,oxidation,etherification,ammonia oxidation,reduction amination,ring rearrangements and others,are frequently used for the above conversions.Among various chemicals obtained from furfural conversions,nitrogen-containing compounds have attracted considerable attention,owing to the wide applications of such type molecules in the synthesis of drug molecules,bioplastics,and other functional materials.Therefore,using furfural as a raw material to synthesize bio-based nitrogenous compounds represents a cutting-edge research direction.In the presence of nitrogen sources,furfural can be transformed into diverse nitrogen-containing compounds through different reactions,such as reduction amination,ammonia oxidation,oxidative coupling,etc.Varied nitrogen sources(e.g.NH3,N2H4·H2O,NH4HCO2,CH3COONH4,(NH4)2CO3 and others),catalysts,reaction atmospheres,and temperatures can result in distinct target products during furfural conversions.Currently,domestic and foreign research groups have made significant progress on furfural conversions to different nitrogen-containing compounds.Therefore,this review aims to briefly outline the recent achievements in the synthesis of high-value nitrogen-containing compounds from furfural through catalytic conversions over different catalysts.The main content includes:(1)synthesizing amines by reduction aminations,e.g.primary,secondary,and tertiary amines;(2)nitriles production by ammonia oxidation;(3)producing amides by amidation;(4)preparing heterocyclic compounds,such as benzoheterocyclic,thiazole,pyrrole,indole,piperidine and pyridine via oxidative cyclization,decarbonylation-amination,reduction amination,hydrogenation,ring rearrangements.The influences of synthesis methods,catalyst types,reaction pathways,mechanisms,as well as the nitrogen sources,on product distributions were discussed in detail.Considering the pathways and products potentially affected by different breakthroughs in the synthesis of nitrogen-containing compounds from furfural can be anticipated from the following aspects:(1)By systematically considering the reaction processes and mechanisms,the construction of composite catalysts and precise adjustment of reaction conditions to integrate multiple reaction steps into one is a trend in this research area to attain more efficient and green conversion processes;(2)Combined experimental with theoretical investigations to comprehensively reveal the reaction pathways during the reaction of different nitrogen sources with furfural;(3)Exploration of new chemical conversion routes and catalysts for the production of more novel nitrogen-containing compounds,to further broaden the application areas of furfural based chemicals.In brief,this review provides a systematical review on the production of furfural based nitrogen-containing chemicals,which would benefit the communities working in biomass utilization areas,and also contribute to the establishment of knowledge of the furfural chemical family.