We are commissioning our plant for production of polycarbonate. After synthesis and separation poymer stream with solvent goes to solvent separation units which have composition pc=23.128%,cb=73.574%,mc=3.234%,water=0.008% where pc=polycarbonate,cb=chlorobenzene,mc=methylene chloride.This stream is at temperature 127°C goes to 1st solvent evaporator where it is heated up to 220°C,resulting product stream contains pc=64% and cb=rest which goes to 2nd solvent separator which is at temperature 260°C. Bottom product stream from 2nd solvent separator contains pc=85% and cb=15%, but in top product we have observed phenol, for which we could not find the reason.Kindly explain the possibilities.