Process for the preparation of polycarbonate

摘要

PCT No. PCT/JP93/00104 Sec. 371 Date Sep. 13, 1993 Sec. 102(e) Date Sep. 13, 1993 PCT Filed Jan. 28, 1993 PCT Pub. No. WO93/15129 PCT Pub. Date Aug. 5, 1993.A polycarbonate which is not discolored and is substantially free from chlorine ions causative of discoloration, has a branching parameter G of 0.1 to 1.0 and, terminal hydroxyl groups of 20 mole % or below based on all the terminal groups of the polycarbonate, and/or, a chlorine ion concentration in the polycarbonate of 10 ppm or below, and/or, a total of an alkali metal ion concentration and an alkaline earth metal ion concentration in the polycarbonate of 1 ppm or below. A process for preparing the above polycarbonate by the melt transesterification process which comprises using a nitrogenous basic compound (a), and/or, a compound (b) containing an element selected from the group consisting of Groups IIb, IVb and Vb of the periodic table; or, a nitrogenous basic compound (a), and, a compound (c) containing an element selected from the group consisting of alkali metals and alkaline earth metals, as a transesterification catalyst.