离子液体催化碳酸二甲酯一步法可控合成生物基聚碳酸酯的研究

Instead of traditional phosgene and diphenyl carbonate melt polymerization methods, developing a new cleaning process for the synthesis of polycarbonate via dimethyl carbonate is an important direction in the field of polycarbonate technology development. Based on the unique physical and chemical properties of ionic liquids, the investigation on the one-step polycarbonate synthetic process via dimethyl carbonate catalyzed by ionic liquid is carried out. The main contents of this project are as follows: 1) Design and synthesis 4-5 kinds of high catalytic activity and high selectivity ionic liquids and investigate the effects of PH value, steric hindrance, substituent group and hydrogen bond network on the polymerization process. 2) Combined with electrospray mass spectrometry, nuclear magnetic resonance, in situ FT-IR and computer simulation, monitor the activation process of monomer duiring the reaction process and develop the synergitic catalytic mechanism. 3) Design 4 kinds of new bio-based monomers and systematically study the effects of structure rigidity, steric resistance and rotational degree of monomer on the properties of polycarbonate, prepare series of bio-based polycarbonates with excellent performance. It provides scientific and theoretical basis for the development of bio-based engineering plastics.

聚碳酸酯（PC）是我国用量最大的热塑性工程塑料，替代传统光气与碳酸二苯酯熔融聚合法，建立碳酸二甲酯（DMC）一步法合成聚碳酸酯清洁工艺是聚碳酸酯领域技术发展的重要方向。针对现有工艺催化体系结构复杂及产品生物毒性等问题，结合离子液体结构可控、酸碱可调及多位点活化等独特性质，本项目拟开展离子液体催化DMC一步法合成生物基聚碳酸酯的研究：拟设计合成3-5类功能化的季铵、季磷、咪唑或吡啶类碱（酸）性离子液体，采用实验分析与分子模拟相结合的手段，考察离子液体酸碱性、阴阳离子空间位阻、取代基及氢键网络结构等对聚合反应过程的影响规律，监测反应过程中单体活性位点的活化过程，揭示阴阳离子的氢键及亲电-亲核两性协同促进聚合链增长机理。同时开发新型生物基聚合单体，考察聚合单体结构刚性、空间位阻及旋转自由度等对聚碳酸酯性能的影响规律，获得性能优良的生物基聚碳酸酯，为生物基工程塑料的发展提供科学依据和理论基础。

聚碳酸酯是一种应用广泛的重要工程塑料，开发新型的绿色催化体系及功能单体，实现其清洁生产及性能提升，对产业升级换代具有重要意义。本项目针对现有工艺催化体系结构复杂及产品生物毒性等问题，结合离子液体结构可控、酸碱可调及多位点活化等独特性质，开展了离子液体催化碳酸二甲酯一步法合成生物基聚碳酸酯的研究：设计合成了具有氢键、静电特殊网络的双酚离子液体、酰亚胺离子液体及双阳离子液体等新型多位点离子液体催化剂，可有效抑制甲基化反应，成功制备了高分子量生物基聚碳酸酯；考察了离子液体阴阳离子结构对生物基聚碳酸酯合成过程的影响规律，获得了离子液体结构与催化性能之间的构效关系；基于实验及模拟相结合的研究结果，揭示了离子液体催化制备生物基聚碳酸酯的机理；采用引入二元醇功能单体共聚的方法，提高了生物基聚碳酸酯的力学和热学性能。该项目建立了基于离子液体的生物基聚碳酸酯制备新路线，降低了环境污染，提升了产品性能，为其后续工业化应用提供了理论基础。