Method for preparing a melt polycarbonate
First Claim
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1. A process for producing polycarbonate comprising:
- a. contacting a dialkyl carbonate with a dihydroxy compound in an oligomerization zone in the presence of an oligomerization catalyst under oligomerization conditions to form a first intermediate; and
b. contacting the first intermediate with a diaryl carbonate in a polymerization zone in the presence of a polymerization catalyst under polymerization conditions to produce the polycarbonatewherein the molar ratio of dihydroxy compound to dialkyl carbonate in the oligomerization zone is at least 2;
1, and wherein the dihydroxy compound is a dihydroxy aromatic compound.
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Abstract
A process for producing polycarbonate comprising: a) contacting a dialkyl carbonate with a dihydroxy compound in an oligomerization zone in the presence of an oligomerization catalyst under oligomerization conditions to form a first intermediate; and b) contacting the first intermediate with a diaryl carbonate in a polymerization zone in the presence of a polymerization catalyst under polymerization conditions to produce the polycarbonate wherein the molar ratio of dihydroxy compound to dialkyl carbonate in the oligomerization zone is at least 2:1.
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Citations
16 Claims
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1. A process for producing polycarbonate comprising:
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a. contacting a dialkyl carbonate with a dihydroxy compound in an oligomerization zone in the presence of an oligomerization catalyst under oligomerization conditions to form a first intermediate; and b. contacting the first intermediate with a diaryl carbonate in a polymerization zone in the presence of a polymerization catalyst under polymerization conditions to produce the polycarbonate wherein the molar ratio of dihydroxy compound to dialkyl carbonate in the oligomerization zone is at least 2;
1, and wherein the dihydroxy compound is a dihydroxy aromatic compound. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification