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Selective Ring‐Opening Polymerization of Non‐Strained γ‐Butyrolactone Catalyzed by A Cyclic Trimeric Phosphazene Base
Author(s) -
Zhao Na,
Ren Chuanli,
Li Huaike,
Li Yunxin,
Liu Shaofeng,
Li Zhibo
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201707122
Subject(s) - phosphazene , superbase , polymerization , polymer chemistry , ring opening polymerization , dispersity , polymer , chemistry , monomer , base (topology) , trimer , catalysis , materials science , organic chemistry , dimer , mathematical analysis , mathematics
A new superbase, the cyclic trimeric phosphazene base (CTPB), was prepared with high yield and purity. In the presence of alcohol, the CTPB serves as a highly efficient organocatalyst for ring‐opening polymerization of the “non‐polymerizable” γ‐butyrolactone to offer well‐defined poly(γ‐butyrolactone) with high conversions (up to 98 %) at −60 °C. The produced polymers have high molecular weights (up to 22.9 kg mol −1 ) and low polydispersity distributions (1.27–1.50). NMR analysis of initiation process and the structural analysis of resulting polymers by MALDI‐TOF suggest a mechanism involving an activating initiator which leads only to linear polymers with BnO/H chain ends.