Chemoselective Alternating Copolymerization of Limonene Dioxide and Carbon Dioxide: A New Highly Functional Aliphatic Epoxy Polycarbonate

• Published in: Angewandte Chemie International Edition 2016-09, Vol.55 (38), p.11572-11576
• Main Authors: Li, Chunliang, Sablong, Rafaël J., Koning, Cor E.
• Format: Article
• Language: English
• Subjects: Acids; Aliphatic compounds; Bearing; Carbon dioxide; Carbonates; Carboxylic acids; Catalysts; Chains; chemoselectivity; Copolymerization; Destruction; epoxy polycarbonates; Functional anatomy; Glass transition temperature; homogeneous catalysis; Insertion; Limonene; Lithium; Polycarbonate; Polycarbonate resins; post-modification; renewable resources; Thiols; Zinc
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201604674

The alternating copolymerization of biorenewable limonene dioxide with carbon dioxide (CO2) catalyzed by a zinc β‐diiminate complex is reported. The chemoselective reaction results in linear amorphous polycarbonates that carry pendent methyloxiranes and exhibit glass transition temperatures (Tg) up to 135 °C. These polycarbonates can be efficiently modified by thiols or carboxylic acids in combination with lithium hydroxide or tetrabutylphosphonium bromide as catalysts, respectively, without destruction of the main chain. Moreover, polycarbonates bearing pendent cyclic carbonates can be quantitatively prepared by CO2 insertion catalyzed by lithium bromide. From biobased diepoxide to linear epoxy PCs: A sustainable poly(limonene‐8,9‐oxide carbonate) was prepared by chemoselective copolymerization of limonene dioxide and CO2. The pendent 2‐methyloxiranyl groups along the polymer chain permit the facile post‐modification and insertion of CO2 to generate cyclic carbonates as functional side groups.