结焦碳化是生物油提质过程中遇到的一个共性的科学问题，严重阻碍了生物油提质技术的应用。本项目拟采用萃取耦合酯化和缩醛化法，抑制生物油提质过程的结焦碳化，研究生物油中活泼性化合物的反应转化规律，揭示生物油易于结焦碳化的内在化学本质；通过制备可同时催化糖类化合物水解、脱水、氧化三步串联反应的多功能分级多孔结构铌氧化物催化剂，考察糖类化合物催化转化过程中的传质与二次反应规律；通过调控催化剂结构和表面性质，研究催化剂的构效关系；将生物油分相萃取和萃取耦合化学转化（酯化/缩醛化）相结合，探索生物油中糖类化合物的定向转化为糠醛和呋喃基甲酸类化合物，并进而缩醛化和酯化制取高品质燃油和化学品的新方法，阐明萃取耦合化学转化提质生物油的耦合作用机制，为开发生物油高值化提供理论依据。

Facile char and coke formation is one of the common and crucial scientific issues in upgrading of bio-oils, which severely precludes the application of various bio-oil upgrading technologies. In this proposal, a novel method for bio-oil upgrading, online solvent extraction coupled with esterification and acetalization reactions, is proposed to prevent from charring and coking and used to elucidate their intrinsic chemical mechanism. By preparing a series of hierarchical meso-macroporous niobium oxides and tailoring their surface properties via doping with active metal sites, it is expected to explore a multifunctional catalyst that can catylze simultaneously three reactions in series, hydrolysis of saccharides to monosaccharose, dehydration of monosaccharose to furfural and 5-hydroxyfurfural, and further aldehyde oxidation to corresponding acids. Our research objectives are: (1) to exlore a new method for directional transformation of the saccharide in bio-oils into valuable chemicals finally by combining the solvent extraction with chemical conversion. and (2) get insight into the coupling mechanism and the changes of the various reactive compound contained in bio-oils and their effects on the esterification and acetalization reactions under online solvent extraction condition. This research work will be helpful for the exploration of novel means of bio-oil upvaluation.