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Principles and design of living cationic polymerization of vinyl monomers: The nature of the growing species based on in‐situ 1 H NMR analysis
Author(s) -
Sawamoto Mitsuo,
Higashimura Toshinobu
Publication year - 1993
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19930670124
Subject(s) - cationic polymerization , carbocation , chemistry , living cationic polymerization , monomer , styrene , ionic bonding , polymerization , polymer chemistry , adduct , nucleophile , nuclear magnetic resonance spectroscopy , halogen , living anionic polymerization , salt (chemistry) , vinyl chloride , medicinal chemistry , anionic addition polymerization , organic chemistry , ring opening polymerization , ion , polymer , copolymer , catalysis , alkyl
This paper focuses on in‐situ 1 H NMR analysis of model reactions that are directed to clarify the nature of the growing species in the following three classes of living cationic polymerization based on the stabilization of the growing carbocations with nucleophilic counteranions and added salts: (a) Vinyl ethers/HCl/SnCl 4 /added n Bu4N+Y‐; (b) Vinyl ethers/HX/ZnCl 2 (salt free); (c) Styrene/HX/SnCl 4 /added n Bu4N+Y‐ (X and Y: halogen) Through the NMR analysis, system (a) provides evidence for the generation of carbocations from adducts [CH 3 CH(OR)Cl] of vinyl ethers and hydrogen chloride and also for the suppression of such ionic species by the added salts. For systems (b) and (c) the spectroscopic observation demonstrated rapid counteranion exchanges in the growing species, indicating that upon reacting with a monomer the living end assumes an ionic character.