Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.
ChemSusChem. 2017 Sep 22;10(18):3547-3556. doi: 10.1002/cssc.201701237. Epub 2017 Sep 19.
New zinc guanidine complexes with N,O donor functionalities were prepared, characterized by X-Ray crystallography, and examined for their catalytic activity in the solvent-free ring-opening polymerization (ROP) of technical-grade rac-lactide at 150 °C. All complexes showed a high activity. The fastest complex [ZnCl (DMEGasme)] (C1) produced colorless poly(lactide) (PLA) after 90 min with a conversion of 52 % and high molar masses (M =69 100, polydispersity=1.4). The complexes were tested with different monomer-to-initiator ratios to determine the rate constant k . Furthermore, a polymerization with the most active complex C1 was monitored by in situ Raman spectroscopy. Overall, conversion of up to 90 % can be obtained. End-group analysis was performed to clarify the mechanism. All four complexes combine robustness against impurities in the lactide with high polymerization rates, and they represent the fastest robust lactide ROP catalysts to date, opening new avenues to a sustainable ROP catalyst family for industrial use.
新的锌胍配合物具有 N,O 供体功能，通过 X 射线晶体学进行了表征，并在无溶剂条件下研究了它们在技术级 rac-丙交酯的开环聚合（ROP）中的催化活性，温度为 150°C。所有配合物都表现出很高的活性。最快的配合物 [ZnCl(DMEGasme)]（C1）在 90 分钟后产生无色聚丙交酯（PLA），转化率为 52%，摩尔质量高（M = 69100，分散度= 1.4）。用不同的单体-引发剂比例测试了这些配合物，以确定速率常数 k。此外，通过原位拉曼光谱监测了最活跃的配合物 C1 的聚合反应。总的来说，转化率高达 90%是可以实现的。进行了端基分析以阐明机理。所有四种配合物都具有对丙交酯中杂质的稳健性和高聚合速率，它们代表了迄今为止最快的稳健丙交酯 ROP 催化剂，为工业用途的可持续 ROP 催化剂家族开辟了新的途径。
