生物油重质组分的精制及其转化机理研究

Bio-oil derived from biomass is sustainable and environmental protection. However, a lot of oligomers remain in bio-oil, and they are nonvolatile, easy to polymerize, and harmful to bio-oil burning, so that the quality of bio-oil were impaired very much. In our project, the acidity ionic liquid ( [Cn(mim)m]Y ) and metal nanoparticles(e.g. Ru-SBA) would be applied in the conversion of these oligomers. With the following research contents proceeded, such as the study of the mechanism on the acidic hydrolysis and hydroprocess, the analysis of influencing factors, the optimization of the reaction selectivity and the integration of upgrading technology, the oligomers would be efficiently converted into little molecule compounds, and the properties of crude bio-oil would be improved. With this research project preformed, we could make clear the characteristic of the oligomers, and understand fully the conversion mechanisms and their corresponding influencing factors. And then, a lot of technologies and experience would be accumulated for the bio-oil upgrading, and so far as to afford the reference to the conversion and utilization of biomass resource.

生物油中高含量的重质组分具有难挥发、易老化和不利于燃烧等特性，严重影响了生物油的品质和产业化进程。针对生物油中重质组分分离难度大、分离方法精制能量损失大的问题，本项目拟根据不同重质组分的结构特征，分步采用酸性离子液体[Cn(mim)m]Y催化酸解低聚糖类物质，采用酸性氧化物(TiO2或SBA)固载的纳米金属粒子（Pd或Ru）催化氢解热解木质素类物质；通过考查降解反应机理及催化剂构效关系、优化反应的选择性和整合精制加工技术等环节的实施，在生物油真实体系中将低聚物高效转化成小分子化合物，从而实现生物油品质的提升。通过本项目的研究不仅可以深入认识生物油中重质组分的形态和特性，还可以弄清其转化机理及影响因素，从而为生物油精制加工积累数据信息和技术经验，同时也可为生物质资源的转化与利用提供依据。

本课题通过催化剂的研制、重质组分降解及机理研究、生物油体系分步精制等方面的探索，对生物油重质组分的精制及其转化机理进行了初步研究。通过改变阴阳离子的结构，合成了一系列双咪唑型酸性、碱性和温控性离子液体，并对其活性进行了考查，Cnmim2-HSO4型酸性双咪唑离子液体的催化性能好，热稳定性较强，且绿色环保；采用掺杂Sn/Zn的钛-锆氧化物为载体，制备了一系列负载金属Pd或Ru的催化剂，并经实验测试，其活性较常规的钯碳要优越，耦合酸性离子液体双重催化作用，不仅提高加氢还原的效果，还能促进醚键的氢解。深入研究了糖类、糠醛类以及酚类化合物在酸性离子液体作用下的转化及产物分布，提出了各自转化的反应机理。酸性离子液体可以通过溶胀和酸解两种方式参与低聚糖的降解，更好地促进低聚糖降解成单糖，继而转化成呋喃类化合物。采用钛/锆氧化物为催化剂载体，可以促进富电子的π键或含氧基团与金属之间的络合，使体系活化，从而促进加氢还原及氢化脱氧。对生物油采用了先酯化、后酸解和氢化还原的分步精制处理，酸性离子液体和负载型金属催化剂可以高效地将重质组分降解，生物油各组分的粘度和酸性得到较大程度地改善，基本实现了根据化合物性质不同而分步精制加工的目的。