Metal-Free Route to Precise Synthesis of Poly(propylene oxide) and Its Blocks with High Activity
writer：Cheng-Jian Zhang, Han-Yi Duan, Lan-Fang Hu, Cheng-Hui Zhang, and Xing-Hong Zhang
keywords：Metal-Free,propylene oxide,High Activity
source：期刊
specific source：ChemSusChem 2018, 11, 4209 – 4213
Issue time：2018年
The fast and living ring-opening polymerization (ROP) of propylene oxide (PO) by metal-free catalysis is reported. By using triethyl borane (TEB) and organic Lewis bases (LBs, e.g.: phosphazene base, amidine and guanidine) as the catalysts, various alkyl alcohols can effectively initiate the ROP of PO, yielding tailor-made poly(propylene oxide)s (PPOs) with high regioregularity, predictable molecular weights, and narrow dispersity approaching Poisson distribution. The TEB/LB catalysts present unprecedentedly high activity (turnover frequency of up to 7500 h-1) and a truly living character for the polymerization, as evidenced by kinetic studies that showed fast initiation and growth, unobserved chain-transfer to PO, chain extension reactions, and the synthesis of various PPO-based block copolymers with narrow dispersities (W<1.1).