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US 4,736,013 AGranted
Method for the preparation of hydroxy-terminated polycarbonate polymers
AssigneeGeneral Electric Company
InventorsSusan J. Hathaway, Kathryn L. Longley, Robert A. Pyles
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Abstract
A method for preparing thermoplastic carbonate polymers terminated with hydroxy groups is disclosed, in which a dihydric phenol is reacted with a carbonyl halide in the presence of a monotetrahydropyranyl ether salt. The hydroxy-terminated polymer is then obtained by cleaving the tetrahydropyranyl group with oxalic acid or a hydrogen halide acid.
Claims14
A method of preparing a hydroxy-terminated thermoplastic polymer having recurring carbonate units in the main chain, comprising:
- (a) reacting a dihydric phenol with a carbonyl halide in the presence of an alkali metal salt of a monotetrahydropyranyl ether of a dihydric phenol, having the formula ##STR3## wherein R is a divalent aromatic compound containing from about 6 to about 30 aromatic carbon atoms and M is an alkali metal ion, said salt being present in an amount effective to control the molecular weight of the resulting polymer;
- and
- (b) removing the tetrahydropyranyl group from the polymer with an effective amount of an acid.
Dependencies are inferred from the claim text.