Processes for producing aromatic/aliphatic copolycarbonate

摘要

Processes for producing an aromatic/aliphatic copolycarbonate which has excellent impact resistance, excellent heat resistance, a high Abbe's number, a low photoelastic coefficient, and an excellent color tone. The processes include those in which: an aromatic/aliphatic copolycarbonate having a nitrogen content of 9 ppm or lower is produced from an aliphatic dihydroxy compound having a nitrogen content of 10 ppm or lower; an aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound having an iron content of 1 ppm or lower; an aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound having a content of aldehyde groups and/or formyl groups of 100 ppm or lower; an aromatic/aliphatic copolycarbonate is produced by subjecting an aromatic dihydroxy compound and an aliphatic dihydroxy compound having a content of free chlorine of 5 ppm or lower to polycondensation with heating and melting; and an aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound which has a melt Hazen unit of 40 or smaller after having been maintained at 260° C. for 5 hours in the air.