ISSN:
0959-8103
Keywords:
polymerization mechanism
;
polymerization kinetics
;
carbonate macrocyclization
;
polycarbonate
;
stopped-flow spectroscopy
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
High yields of cyclic oligomeric carbonates can be prepared using an amine-catalyzed reaction of bisphenol A-bischloroformate. We have studied the mechanistic aspets of this carbonate macrocyclization by the isolated study of key chemical events. Using stopped-flow FT-IR spectroscopy, we have found that the rate of carbonate formation between the intermediate acyl ammonium salt and 4-isopropylphenol is the same for the acyl ammonium salt derived from tri-n-butylamine, triethylamine and diethylmethylamine. Previously, we found that conversion of acyl ammonium salt to urethane was also insensitive to amine structure while the formation of acyl ammonium salt is profoundly dependent on amine structure. These results are consistent with a mechanism in which the selectivity toward macrocyclization versus linear oligomer or high polymer formation is related to acyl ammonium salt concentration.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pi.1994.210330206
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