Bismuth(III) Alkoxide Catalysts for Ring‐Opening Polymerization of Lactides and ϵ‐Caprolactone. Issue 6 (24th January 2013)

• Record Type: Journal Article
• Authors: Vuorinen, Sirpa; Lahcini, Mohammed; Hatanpää, Timo; Sundberg, Markku; Leskelä, Markku; Repo, Timo
• Is Part Of: Macromolecular chemistry and physics. Volume 214:Issue 6(2013:Mar.)
• Page Start: 707
• Page End: 715
• Publication Date: 2013-01-24
• Subjects: Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201200521
• Languages: English
• ISSNs: 1022-1352

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Homoleptic bismuth alkoxide complexes, Bi(OR)₃ [R = ⁱPr (<bold>1</bold>), ^tBu (<bold>2</bold>), and CMe₂ⁱPr (<bold>3</bold>)], are used as catalysts in the ring‐opening polymerization (ROP) of lactides. In contrast to <bold>1</bold>, two bulkier bismuth alkoxides, <bold>2</bold> and <bold>3, </bold> show high activity in the ROP of lactides in toluene at 75 °C. Notably, Bi^III alkoxides <bold>2</bold> and <bold>3</bold> are more active in lactide ROP than Sn^II octoate activated with <italic>n</italic>‐butanol under identical reaction conditions. Bismuth alkoxides <bold>2</bold> and <bold>3</bold> exhibit a living behavior in the ROP of lactides that is demonstrated both in homopolymerization and in a polymerization resumption experiment. Polymerization of <italic>rac</italic>‐lactide using <bold>2</bold> and <bold>3</bold> yields polylactide with a slight heterotactic bias. In addition, <bold>2</bold> is an efficient initiator for the ROP of ϵ‐caprolactone in bulk at 120 °C. Variation of the monomer‐to‐catalyst ratio yielded poly(ϵ‐caprolactone) with <overline><italic>M</italic></overline>_ns up to 120 000 g mol⁻¹ in corrected gel‐permeation chromatography (GPC) data.</p> </abstract>