Polymers of carbonic acid, 21. Ring‐opening polymerization of cyclobis(diethylene glycol carbonate) by means of BuSnCl 3 , SnOct 2 or Bu 2 SnO as catalysts

• Published in: Macromolecular Chemistry and Physics
• Main Authors: Kricheldorf, Hans R., Lossin, Martina, Mahler, Andreas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1997
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/macp.1997.021981119; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fmacp.1997.021981119; https://onlinelibrary.wiley.com/doi/pdf/10.1002/macp.1997.021981119

Abstract Cyclobis(diethylene glycol carbonate), (DEGC) 2 , was synthesized by polycondensation of diethylene glycol with diethyl carbonate followed by thermal depolymerization of the crude polycarbonate in vacuo. BuSnCl 3 ‐initiated polymerizations of (DEGC) 2 in chlorobenzene at 100°C gave poor results. Therefore, all further polymerizations were conducted at 145°C in bulk. Two series of polymerizations were performed with BuSnCl 3 as catalyst, so that either the time was varied at constant monomer/initiator (M/I) ratio, or the M/I ratio at constant time. Two analogous series were conducted with SnOct 2 With both catalysts high yields but only moderate molecular weights were obtained. SnOct 2 yielded polycarbonates having octoate end‐groups, which were detected by 1 H NMR spectroscopy. (DEGC) 2 was also polymerized with Bu 2 SnO at M/I = 200 or 500 with variation of time. The highest yields and molecular weights were obtained at the shortest time, whereas longer times caused rapid depolymerization. Therefore, Bu 2 SnO appeared to be the most reactive catalyst. Both 1 H and 13 C NMR spectra proved that all poly(diethylene glycol carbonates) prepared in this work possess an alternating sequence of ether and carbonate groups.