Process for producing polycarbonate oligomers
First Claim
1. A process for producing polycarbonate oligomers by the reaction of dihydroxy compounds with phosgene, which comprises contacting a mixture of a dihydroxy compound and an aqueous alkali solution with phosgene in the presence of an organic solvent in a tubular reactor to perform a first-stage reaction wherein the reaction time is from 0.5 to 15 seconds, introducing the first-stage reaction mixture into a tank-type reactor equipped with a stirrer and containing the aqueous alkali solution and a solution in the organic solvent of a polycarbonate oligomer formed by the reaction of the first-stage reaction product in a second stage, and performing the second-stage reaction, wherein the reaction time is from 5 to 20 minutes, while stirring the reaction mixture in the tank-type reactor and maintaining it at a predetermined temperature by sufficient removal of the heat of reaction.
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Abstract
A process for producing polycarbonate oligomers by the reaction of dihydroxy compounds with phosgene, which comprises contacting a mixture of a dihydroxy compound and an aqueous alkali solution with phosgene in the presence of an organic solvent in a tubular reactor to perform a first-stage reaction, introducing the first-stage reaction mixture into a tank-type reactor equipped with a stirrer and containing the aqueous alkali solution and a solution in the organic solvent of a polycarbonate oligomer formed by the reaction of the first-stage reaction product in a second stage, and performing the second-stage reaction while stirring the reaction mixture in the tank-type reactor and maintaining it at a predetermined temperature by sufficient removal of the heat of reaction.
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Citations
5 Claims
- 1. A process for producing polycarbonate oligomers by the reaction of dihydroxy compounds with phosgene, which comprises contacting a mixture of a dihydroxy compound and an aqueous alkali solution with phosgene in the presence of an organic solvent in a tubular reactor to perform a first-stage reaction wherein the reaction time is from 0.5 to 15 seconds, introducing the first-stage reaction mixture into a tank-type reactor equipped with a stirrer and containing the aqueous alkali solution and a solution in the organic solvent of a polycarbonate oligomer formed by the reaction of the first-stage reaction product in a second stage, and performing the second-stage reaction, wherein the reaction time is from 5 to 20 minutes, while stirring the reaction mixture in the tank-type reactor and maintaining it at a predetermined temperature by sufficient removal of the heat of reaction.
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