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Macrocycles, 7. Cyclization of oligo‐ and poly(ethylene glycol)s with dibutyltin dimethoxide – a new approach to (super)macrocycles
Author(s) -
Kricheldorf Hans R.,
Langanke Dennis
Publication year - 1999
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19990501)200:5<1174::aid-macp1174>3.0.co;2-g
Subject(s) - polymer chemistry , ethylene glycol , polymer science , chemistry , materials science , organic chemistry
When commercial oligo‐ or poly(ethylene glycol)s and dibutyltin dimethoxide were condensed in bulk with elimination of methanol, no linear polycondensates were obtained and tin‐containing macrocycles were the only reaction products. In order to improve the hydrolytic stability, stoichiometric amounts of γ ‐thiobutyrolactone were inserted into the macrocyclic oligoethers, so that the Sn—O bonds were transformed into Sn—S bonds. The formation of monomeric (containing one Bu 2 Sn group) macrocycles was confirmed. The tin‐containing macrocyclic polyethers were used as macrocyclic initiators for the ring‐expansion polymerization of ε ‐caprolactone. The resulting macrocyclic poly(ether‐ester)s were isolated in the form of telechelic A‐B‐A block copolymers after precipitation into methanol.