H-Bonding Organocatalysts for the Living, Solvent-Free Ring-Opening Polymerization of Lactones: Toward an All-Lactones, All-Conditions Approach
Document Type
Article
Date of Original Version
11-28-2017
Abstract
The developing urea class of H-bond donors facilitates the solvent-free ROP of lactones at ambient and elevated temperatures, displaying enhanced rates and control versus other known organocatalysts for ROP under solvent-free conditions. The ROPs retain the characteristics of living polymerizations despite solidifying prior to full conversion, and copolymers can be accessed in a variety of architectures. One-pot block copolymerizations of lactide and valerolactone, which had previously been inaccessible in solution phase organocatalytic ROP, can be achieved under these reaction conditions, and one-pot triblock copolymers are also synthesized. For the ROP of lactide, however, thioureas remain the more effective H-bond donating class. For all (thio)urea catalysts under solvent-free conditions and in solution, the more active catalysts are generally more controlled. A rationale for these observations is proposed. The triclocarban (TCC) plus base systems are particularly attractive in the context of solvent-free ROP due to their commercial availability which could facilitate the adoption of these catalysts.
Publication Title, e.g., Journal
Macromolecules
Volume
50
Issue
22
Citation/Publisher Attribution
Pothupitiya, Jinal U., Nayanthara U. Dharmaratne, Terra Marie M. Jouaneh, Kurt V. Fastnacht, Danielle N. Coderre, and Matthew K. Kiesewetter. "H-Bonding Organocatalysts for the Living, Solvent-Free Ring-Opening Polymerization of Lactones: Toward an All-Lactones, All-Conditions Approach." Macromolecules 50, 22 (2017): 8948-8954. doi: 10.1021/acs.macromol.7b01991.