疏水/酸性双功能化离子液体合成及其催化生物质转化制备高附加值化学品研究

Biomass is one of the renewable resources that can be used as substitute to fossil fuels in obtaining carbon-based fuels and high added-value chemicals, but there is scarce efficient catalysts in biomass tranformation. Synthesis of hydrophobic/bianionic functionalized ionic liquids,which have different apparent acidities, by engrafting functional groups on cations and exchanging anions in concatenation upon the structural tunability of ionic liquids. The structure of these functionalized ionic liquids was characterized by NMR,IR,and IMS,etc. The apparent acidity of these different functionalized ionic liquids was characterized by UV-vis spectra. Based on the characterization,the relationship of acidity-structure of these functionalized ionic liquids was deduced. The catalytic performance of these different functionalized ionic liquids was investigated at length in converting biomass (cellulose,oligosaccharide,etc) into platform molecules (C6-alcohols, glucoside, etc) or high added-value chemicals （2,5-dimethylfuran,hydroxymethylfurfural, etc） in using as substitutes to acidic catalysts of liquid or solid. Moreover, the novel functionalized ionic liquids,which are more efficient catalysts in transformation biomass into platform molecules or high added-value chemicals, are designed and synthesized under the guidance of the relationship of catalytic performance and acidity that induced from the above results. The implementation of synthesis of hydrophobic/acidic bianionic functionalized ionic liquids and their application in converting biomass into high added-value chemicals has important effect in both the development of the novel functionalized ionic liquids and the exploitation of novel processes for biomass transformation.

生物质是替代石油获得碳基高附加值化学品和燃料的一种可再生资源，但缺乏有效转化的催化剂体系。本研究利用离子液体结构的可调变性，通过控制反应物的量分步进行阳离子功能化修饰反应和阴离子交换反应，合成具有不同表观酸度的新型双阴离子疏水性功能化离子液体；通过核磁，红外，离子质谱等表征确证功能化离子液体结构，紫外可见分光光度法表征确立离子液体相对酸度，建立离子液体酸度与结构关系；进而用功能化离子液体替代液体或固体形态酸性催化剂，系统研究其在生物质（如寡聚糖和纤维素）转化为平台分子（如C6醇和葡萄糖苷）及高附加值化学品（如2,5-二甲基呋喃）过程中的催化性能。初步建立离子液体酸度和催化性能间的基本关系，进一步开发适于生物质高效转化的新型功能化离子液体催化剂。本项目的开展对新型功能化离子液体的创制，生物质转化制备生物基燃料和高附加值化学品新途径的探索具有重要的科学和实际意义。

能源是人类社会发展的基础保障。随着人类社会的迅速发展，社会发展对能源的需求不断增长和化石资源有限储量之间的矛盾日益突出。为了缓和这一矛盾，人们将目光转移到太阳能、风能、生物质能等可再生资源的利用。尤其是生物质资源的有效利用，不仅能够满足日益增长的能源需求，而且能够提供丰富多样的高附加值化学品。为了实现纤维素糖类的有效转化，本项目设计合成了多种功能化离子液体用于纤维素糖类转化制备高附加值化学品研究。(1)两种不同阴离子共存于一体的疏水/Brönsted酸性双功能化离子液体在温和条件下能够使低聚糖如纤维二糖有效转化，产物选择性达到99%；而将这类离子液体用于纤维素醇解反应时，相对于高结晶度纤维素，低结晶度纤维素能够被有效转化为烷基葡萄糖苷。(2) Lewis酸性功能化离子液体也被用于呋喃酚合成及纤维素水解转化反应，该种离子液体是合成呋喃酚的有效催化剂，亦能促使纤维素水解成葡萄糖。(3)醚基功能化离子液体则可能提高纤维素的溶解。离子液体体系处理纤维素糖类是生物质高效转化途径的有益探索，丰富了生物质转化方式。