An Efficient Method of Depolymerization of Poly(cyclopentene carbonate) to Its Comonomers: Cyclopentene Oxide and Carbon Dioxide

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• 作者：Donald J. Darensbourg ; Sheng-Hsuan Wei ; Andrew D. Yeung ; W. Chadwick Ellis
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：August 13, 2013
• 年：2013
• 卷：46
• 期：15
• 页码：5850-5855
• 全文大小：322K
• 年卷期：v.46,no.15(August 13, 2013)
• ISSN：1520-5835

文摘

The hydroxyl-terminated copolymer, poly(cyclopentene carbonate), derived from carbon dioxide and cyclopentene oxide was deprotonated by the strong base sodium bis(trimethylsilyl)amide (NaHMDS) in toluene and shown to undergo depolymerization to cyclopentene oxide and cis-cyclopentene carbonate. The degradation process was demonstrated to be retarded under a 0.7 MPa pressure of CO₂, with the product distribution being enhanced in favor of cis-cyclopentene carbonate. Unlike the related copolymer, poly(indene carbonate), the degradation pathway was found to be insensitive to either light or the radical trap, TEMPO. The depolymerization process was further shown to be catalyzed by (salen)CrCl/n-Bu₄NN₃, with the major product being cyclopentene oxide. Although the reaction rate in the presence of metal catalyst was inhibited by an added pressure of CO₂, the product distribution still highly favored epoxide production. On the other hand, upon reducing the pressure above the polymer solution during the depolymerization reaction, the rate of reaction was accelerated and was more selective for cyclopentene oxide formation. Preliminary studies were investigated to optimize the efficient recycling of poly(cyclopentene carbonate) to its monomers, cyclopentene oxide and CO₂. Computational studies have been performed on depolymerization reaction of polycarbonates derived from CO₂ and epoxides which strongly support these experimental findings.