EXTRACTION OF UNREACTED PHENOLIC COMPOUND

摘要

PROBLEM TO BE SOLVED: To provide a process for the efficient and quick extraction of an unreacted phenolic compound in a reaction waste water generated in the production of a polycarbonate resin. SOLUTION: A polycarbonate resin is produced by reacting an alkaline aqueous solution of a phenolic compound with phosgene in the presence of an organic solvent. In the above process, an unreacted phenolic compound is extracted into the organic solvent phase from a reaction waste water containing the unreacted phenolic compound and generated from the reaction system. The extraction is carried out by preparatorily mixing the reaction waste water containing the unreacted phenolic compound with the organic solvent, adding a pH modifier to the mixture to adjust the pH of the reaction waste water to 5-10 and mixing the reaction waste water with the organic solvent to effect the extraction of the unreacted phenolic compound to the organic solvent phase.