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Rates of carbonate bond formation: Implications for macrocyclization
Author(s) -
Aquino Eugene,
Brittain William J.,
Brunelle Daniel J.
Publication year - 1994
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1994.210330206
Subject(s) - triethylamine , chemistry , salt (chemistry) , amine gas treating , ammonium , butylamine , carbonate , selectivity , polymer chemistry , oligomer , organic chemistry , catalysis
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.