title: 1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions.
abstract: The ring-opening polymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA) under solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as precatalyst is described. Linear and star-branched polyesters were synthesized by successive use of benzyl alcohol, ethylene glycol, glycerol and pentaerythritol as initiator alcohols, and the products were fully characterized by (1)H and (13)C{(1)H} NMR spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). BMIM-2-CO2 acts as an N-heterocyclic carbene precursor, resulting from in situ decarboxylation, either by heating under vacuo (method A) or by addition of NaBPh4 (method B). Possible catalytic and deactivation mechanisms are proposed.
authors.affiliation: Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR CNRS 6302, Avenue A. Savary, BP 47870, F-21078 Dijon, France.
authors.forename: Astrid
authors.initials: A
authors.lastname: Hoppe
authors.forename: Faten
authors.initials: F
authors.lastname: Sadaka
authors.forename: Claire-Hélène
authors.initials: CH
authors.lastname: Brachais
authors.forename: Gilles
authors.initials: G
authors.lastname: Boni
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Couvercelle
authors.forename: Laurent
authors.initials: L
authors.lastname: Plasseraud
keywords: N-heterocarbene precursor; aliphatic polyesters; green polymerization reaction; imidazolium-2-carboxylates; organocatalysis