Low‐Temperature Polymerization of ε‐Caprolactone Catalyzed by Cerium Triflates. Issue 18 (29th July 2013)

• Record Type: Journal Article
• Authors: Weidner, Steffen M.; Scheliga, Felix; Kricheldorf, Hans R.
• Is Part Of: Macromolecular chemistry and physics. Volume 214:Issue 18(2013:Sep.)
• Page Start: 2043
• Page End: 2053
• Publication Date: 2013-07-29
• Subjects: Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201300279
• Languages: English
• ISSNs: 1022-1352

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Using 22 metal triflates as catalysts, ε‐caprolactone is polymerized at 22 °C in bulk. Only five relatively acidic triflates prove active. Three triflates, including the neutral Sm³⁺, are active using water as initiator. A very low content of cyclics is found in all the experiments. With Ce³⁺ and Ce⁴⁺, polymerizations are performed in CH₂Cl₂ and in bulk at 2 °C and 22 °C. Low dispersities (down to 1.1) are obtained. At 22 °C, Ce⁴⁺ and, even better, Ce³⁺ also catalyze syntheses of CO₂H‐ and CH₂OH‐terminated polycaprolactones, whereby higher dispersities and larger fractions of cyclics are obtained. Further polymerizations and polycondensations are catalyzed with protic acids. The results can be explained by a proton‐catalyzed activated monomer mechanism. <boxed-text content-type="graphic" position="anchor" orientation="portrait"><graphic position="anchor" mimetype="image" xlink:href="ark:/27927/pgg3hsm2dmd" orientation="portrait" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /></boxed-text></p> </abstract>