纤维素醇解制备乙酰丙酸酯的研究进展

摘要

乙酰丙酸酯是一类具有成为新一代生物燃料或者燃料添加剂潜力的高附加值化学品,通过醇解制备乙酰丙酸酯是纤维素资源化利用的重要途径.本文系统地综述了纤维素在酸催化条件下醇解制备乙酰丙酸酯的最新研究进展,重点介绍了在纤维素醇解过程中研究较为活跃的无机酸、固体酸、混合酸和离子液体等几类主要催化剂的催化效果,并总结了这几类催化剂所具有的优势和劣势.同时,着重分析了其醇解机理,特别是Lewis酸和Bronsted酸在纤维素糖苷键断裂、葡萄糖单元异构化为果糖单元以及果糖单元进一步转化为乙酰丙酸酯等过程中不同的催化作用.并指出目前纤维素醇解制备乙酰丙酸酯过程中仍存在反应条件苛刻、选择性低、反应机理不清甚至相互矛盾等问题.未来研究的主要方向是必须系统地研究纤维素醇解的详细机理,以及在此基础上设计合成催化活性和选择性更高的催化剂.%Levulinate esters is a kind of high value-added chemicals that could become a new generation of biofuels or fuel additives through alcoholysis for the utilization of cellulose resource.This paper reviewed the recent research progress of the preparation of levulinate esters through alcoholysis of cellulose under the conditions of acid catalysts systematically,and focused on introducing the catalytic effect of several kinds of catalysts researched in the filed such as inorganic acids,solid acids,mixed acids,and ionic liquids.The advantages and disadvantages of these catalysts were summarized.The mechanism of alcoholysis was discussed as well as the different catalytic role of Lewis and Bronsted acids in the process of cleavage of glycosidic bond,isomerization from glucose unit into fructose unit,and further conversion of fructose unit into levulinate.The existing problems in the research of alcoholysis,such as harsh reaction conditions,low selectivity,unclear reaction mechanism were discussed.The future research directions of studying the details of cellulose alcoholysis mechanism and designing and synthetizing catalysts with higher activity and selectivity were pointed out.