Theoretical Mechanistic Investigation into Metal-Free Alternating Copolymerization of CO2 and Epoxides: The Key Role of Triethylborane
KAUST DepartmentDivision of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
KAUST Catalysis Center, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
Physical Science and Engineering (PSE) Division
Chemical Science Program
Office of the VP
KAUST Catalysis Center (KCC)
Embargo End Date2019-08-14
Permanent link to this recordhttp://hdl.handle.net/10754/670059
MetadataShow full item record
AbstractThe copolymerization of carbon dioxide (CO2) and epoxides has received much attention during the past decades for the production of aliphatic polycarbonates. Remarkably, the green synthesis of polycarbonates was recently demonstrated by copolymerization of CO2 with epoxides under metal-free conditions. In this work, the reaction mechanism of this highly selective polymerization was further investigated using DFT calculations. Four steps were studied: step I describes the epoxide ring-opening by the chloride anion in the presence of the Lewis acid triethylborane (TEB); step II is related to the subsequent insertion of CO2; step III corresponds to the alternating insertion of an epoxide facilitated by TEB; step IV is characterized by the leaving of TEB followed by a new round of polymerization. The high selectivity to form alternating polycarbonates and the suppression of backbiting and homopolymerization that respectively generate cyclic carbonates and polyethers were confirmed by the difference of energy barriers. The key role of TEB at every step was also elucidated. Our theoretical results support the proposed experimental outcomes and provide the fundamental mechanistic insights.
CitationZhang, D.-D., Feng, X., Gnanou, Y., & Huang, K.-W. (2018). Theoretical Mechanistic Investigation into Metal-Free Alternating Copolymerization of CO2 and Epoxides: The Key Role of Triethylborane. Macromolecules, 51(15), 5600–5607. doi:10.1021/acs.macromol.8b00471
SponsorsThis work is supported by King Abdullah University of Science and Technology (KAUST).
PublisherAmerican Chemical Society (ACS)