Process for the neutralization of residual acid species in crude dihydric phenols
First Claim
Patent Images
1. A method of preparing polycarbonate by the melt process, comprising:
- combining a thermally stable organic base with a crude dihydric phenol in the presence of a sulfonic acid compound and in the absence of an alkali metal compound or an alkaline earth metal compound to form a dihydric phenol;
melting the dihydric phenol and a diester of carbonic acid for a time and at a temperature sufficient to form a melt product;
combining the melt product with a catalyst comprising the alkali metal compound, the alkaline earth metal compound, a quaternary ammonium compound, a quaternary phosphonium compound, or a combination thereof;
oligomerizing the melt product; and
polymerizing the melt product.
3 Assignments
0 Petitions
Accused Products
Abstract
The present invention relates to a method of neutralizing residual acid species in crude dihydric phenol comprising the step of introducing a thermally stable organic base selected from the group consisting of tetraalkyl phosphonium hydroxides, tetraorganophosphonium carboxylic acid salts, or a mixture thereof into the crude dihydric phenol.
7 Citations
19 Claims
-
1. A method of preparing polycarbonate by the melt process, comprising:
-
combining a thermally stable organic base with a crude dihydric phenol in the presence of a sulfonic acid compound and in the absence of an alkali metal compound or an alkaline earth metal compound to form a dihydric phenol;
melting the dihydric phenol and a diester of carbonic acid for a time and at a temperature sufficient to form a melt product;
combining the melt product with a catalyst comprising the alkali metal compound, the alkaline earth metal compound, a quaternary ammonium compound, a quaternary phosphonium compound, or a combination thereof;
oligomerizing the melt product; and
polymerizing the melt product. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method of preparing polycarbonate by the melt process, comprising:
-
combining a thermally stable organic base selected from the group consisting of tetraalkyl phosphonium hydroxides, tetraorganophosphonium carboxylic acid salts, and mixtures thereof, with a crude dihydric phenol in the presence of a sulfonic acid compound and in the absence of an alkali metal compound or an alkaline earth metal compound to form a dihydric phenol, wherein the thermally stable organic base is present in an amount sufficient to neutralize the sulfonic acid compound;
melting the dihydric phenol and a diester of carbonic acid for a time and at a temperature sufficient to form a melt product;
combining the melt product with a catalyst comprising the alkali metal compound, the alkaline earth metal compound, a quaternary ammonium compound, a quaternary phosphonium compound, or a combination thereof;
oligomerizing the melt product; and
polymerizing the melt product. - View Dependent Claims (16, 17, 18, 19)
-
Specification