富含衣康酸单元的聚氨酯超细纤维固载离子介质催化剂的制备与催化转化5-羟甲基糠醛的研究

In this proposal, the designable property of the main molecular segment in polymer chain is utilized to prepare itaconic acid unit enriched polyurethane ultrafine fibers by synthesis and electrospinning. And then, imidazole-type catalytic active sites are induced to be loaded by the carbon-carbon double bonds, which are existed in the itaconic acid units. So that a kind of solid-supported catalyst to convert for bio-based active monomer 5-hydroxymethylfurfural (5-HMF) is fabricated. By controlling the distribution and the sequence structure of the active sites, the relation between the hierarchical structures and catalytic activity is elucidated in detail. The principle and method to control catalytic activity will be obtained. And The conversion efficiency and selectivity from sugars to 5-HMF is guided to be improved. The catalyst obtained from this proposal exhibits a precise molecular structure and controllable activity and it also has the advantages of non-toxic, easy separation, reusable and processible. As a result, this research exhibits a novel routine to do the research on catalyst carrier and solid-supported catalyst. It also provides the important scientific dependence in fabricating high efficient catalytic reactor. With the development of this study and the progress in technology, it will assist to improve the transformation from biomass to 5-HMF and produce adequate bio-based active monomer containing with the structure of conjugated rigid ring. Finally, this technique will inspire the improvement of the manufacture activity of bio-based polymers.

本项目主要利用聚合物的分子片段设计特性，合成并电纺制备富含衣康酸单元的聚氨酯超细纤维，以衣康酸单元内的碳碳双键引导咪唑类离子介质催化活性位点的固载，得到用于催化转化5-羟甲基糠醛（5-HMF）的固载型催化剂。通过催化活性位点分布状态和序列结构调控，阐明催化剂各级结构与催化活性间关系，掌握控制固载型催化剂活性的原理方法，指导催化糖类化合物转化为5-HMF的转化率及选择性的提升。该项目得到的催化剂结构精确、活性可控，具有无毒、易分离、可重复利用、加工性好等优点，因此为设计制备新型催化剂载体和固载型催化剂提供了新思路，也为构建高效催化反应器提供了重要的科学依据。随着对超细纤维固载型催化剂研究的不断深入和技术的日趋成熟，将最终辅助提升生物质原料向5-HMF的转化水平，为合成高性能高分子材料提供充足含刚性共轭环结构的活性单体，由此带动生物基高分子材料的整体制造水平的提升。

本项目主要研究了富含衣康酸单元聚氨酯的合成、电纺、离子介质固载及其功能性。通过优化分子结构设计，成功合成了富含衣康酸单元的聚氨酯材料，并经电纺得到形貌均匀的超细纤维，而后利用衣康酸单元中的碳碳双键实现交联与固载功能化。进一步地，提出以含咪唑的扩链剂实施富含衣康酸单元聚氨酯材料合成的新技术路线，成功合成了含有大量活性位点的衣康酸基聚氨酯，在材料的合成过程中对功能化和交联进行了有效区分。将这种包含咪唑功能活性位点的富含衣康酸单元聚氨酯进行电纺及后处理，最终得到了性能优越的超细纤维固载型催化剂。该材料的功能性良好，经抗菌测试，抗菌率超过90%。用于催化亚磷酸二乙酯合成α-氨基膦酸盐的产率达到80%、催化果糖转化5min即能达到86%的转化率且产物以5-羟甲基糠醛为主。