| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polycarbonate capable of inhibiting accumulation of diester carbonate and clogging of a scrubber, and having excellent quality for a long time by crystallizing diester carbonate from a specific scavenging liquid discharging from the scrubber and separating. SOLUTION: The objective polycarbonate is obtained by polycondensation reacting an aromatic dihydroxy compound with diester carbonate in the presence of a catalyst in an apparatus having a vacuum scavenging system including a process in which a polymerization generating material is introduced to a scrubber using a specific scavenging liquid, brought into contact with the scavenging liquid kept at a specific temperature and a monohydroxy compound generated in a reactor is condensed with a diester carbonate, a process crystallizing the diester carbonate from the scavenging liquid discharged from the scrubber, a process in which the crystallized diester carbonate is separated from the scavenging liquid and the diester carbonate is recovered from the separated crystal and a process in which the monohydroxy compound is separated from the scavenging liquid separated the crystal, as necessary, and the residue is circularly used as a scrubber scavenging liquid.
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