葡萄糖催化制备5-羟甲基糠醛研究新进展

Recent advances in catalytic systems for the preparation of 5-HMF from glucose

平台化合物的制备对于生物质资源的高效利用具有重要意义。5-羟甲基糠醛(5-hydroxymethylfurfural, 5-HMF)作为重要的生物质平台化合物,可以转化成生物燃料和众多高附加值的化学品(乙酰丙酸、2,5-呋喃二甲酸、γ-戊内酯等),在生物炼制中占据极其重要的地位。因此,开发低成本、可规模化生产5-HMF的路线成为生物质催化转化领域的热点。纤维素水解可以得到大量葡萄糖,因此由葡糖糖脱水制备5-HMF具有原料资源丰富的优势。为了实现葡萄糖到5-HMF的高效转化,催化体系的设计和选择是关键因素。催化体系主要包括反应溶剂和反应催化剂,其中反应溶剂体系主要包括一元体系(水相或有机相)、二元体系(水-有机或有机-有机)、多元体系和离子液体体系等。反应催化剂主要分为均相催化剂(无机酸、有机酸和金属盐)、非均相催化剂和金属有机骨架材料等。目前在葡萄糖制备5-HMF过程中,高效催化体系的开发依然存在诸多挑战。笔者主要就近年来国内外催化葡萄糖制备5-HMF的催化体系最新研究进展加以综述,重点概述了葡萄糖制备5-HMF的形成机理、溶剂体系以及催化剂类型,并对葡萄糖制备5-HMF的发展前景进行了展望,以期对葡萄糖的催化转化机制进行充分阐释,对新型催化体系的设计提供理论指导。

The preparation of platform compounds was important for the efficient conversion of biomass resources into fuels and bulk chemicals.As a typical biomass-based platform compound,5-hydroxymethylfurfural(5-HMF) can be converted into biofuels and diverse value-added chemicals,including levulinic acid,2,5-furandicarboxylic acid γ-valerolactone.The 5-HMF preparation plays an extremely important role in the bio-refinery process.Therefore,it is of special importance to develop scalable and low-cost 5-HMF synthesis technique with industrial potential,which has attracted increasing research interests.Glucose can be obtained from hydrolysis of the nature abundant cellulose,and 5-HMF can be prepared by dehydration of glucose.Although 5-HMF can be directly obtained from fructose,it is regarded as an economic way to prepare 5-HMF from glucose compared to fructose.In the catalytic conversion process from glucose to 5-HMF,the catalytic system is very crucial.The efficient production of 5-HMF could be realized by a rational catalytic system design,including the construction of catalysts and solvents screening.In general,the catalytic system can be divided into solvents and catalysts.The reaction solvent systems for 5-HMF preparation mainly includes single solvent system(water phase or organic phase),binary solvent system(water/organic or organic/organic),multiple solvent system and ionic liquid system.The type of catalysts can be divided into homogeneous catalysts(inorganic acid,organic acid and metal salt),heterogeneous catalysts and metal organic frameworks.There are still many challenges remained in the development of efficient catalytic system for the preparation of 5-HMF from glucose.Several concerns should be addressed before the industrial production of 5-HMF.Here,the research progress of the 5-HMF synthesis from glucose in recent years is summarized,and the mechanism,solvent system and catalyst system of 5-HMF preparation from glucose are discussed emphatically,and the future development prospect of 5-HMF preparation from glucose is prospected.Aiming at achieving relatively high 5-HMF yields from glucose,this review mainly analyzes the design principle for the catalysts,elaborates the relationships between catalyst and solvents system.In particular,special attention is paid to the reaction routes over different various catalytic systems and underlying connections.The strategies for the restriction of undesired side reactions have also been discussed.The main findings summarized in this review will benefit the research related to the development of efficient catalytic systems for preparing 5-HMF with high efficiency.The existing major challenges,promising solutions and future research directions during the 5-HMF catalytic synthesis were listed in the last part,which could be helpful for the deeper understanding of biomass conversion and utilization.