沸石咪唑酯骨架-67高效催化L-丙交酯的开环聚合反应

Zeolitic Imidazolate Framework-67 Efficiently Catalyzes the Ring-Opening Polymerization of L-Lactide

为了探究沸石咪唑酯骨架材料(Zeolitic Imidazolate Frameworks,ZIFs)结构中的金属单元对其催化活性的影响,我们采用室温法合成了ZIF-8、Zn/Co-ZIF和ZIF-67,并用其催化L-丙交酯的本体开环聚合反应。在相同的反应条件下,ZIF-67具有最高的催化活性。与2-甲基咪唑(配体)作为催化剂相比,ZIF-67催化得到的聚乳酸具有高度全同立构结构。此外,基质辅助激光解吸-飞行时间(MALDI-TOF)质谱表明,ZIF-67催化得到的聚乳酸主要为线状结构。经过3次循环反应后,ZIF-67的催化活性没有明显降低。

To explore the metal effecting in structure of zeolitic imidazolate frameworks( ZIFs) influenced to its catalytic activity,we have synthesized ZIF-8,Zn/Co-ZIF and ZIF-67 by room temperature method and applied them as catalysts for the bulk ring-opening polymerization of L-lactide. Under the same reaction condition,ZIF-67 shows the highest catalytic activity. Compared to 2-methylimidazolate( linker) as a catalyst under the same reaction condition,the poly( lactic acid) obtained with ZIF-67 has highly isotactic structure.In addition,the matrix assisted laser desorption ionization-time of flight( MALDI-TOF) mass spectrum indicate that the poly( lactic acid) obtained with ZIF-67 has an almost linear structure. ZIF-67 can be reused for three times without significantly loss of catalytic activity.