Abstract: Disclosed herein is a polycarbonate copolymer comprising repeating units respectively made of a bisphenol A and a tetrahalogenobisphenol A and having a trihalogenophenoxy group as an end group at the terminal, particularly both terminals thereof and a method for efficiently producing said polycarbonate copolymer. This polycarbonate copolymer is superior in impact resistance, flame retardance, molding thermostability and the like, is good in hydrolytic resistance, is much less liable to cause a mold rust and has high quality. Therefore, this polycarbonate copolymer will be extensively used in various industrial materials, for example as the flame retardant parts for household electric appliances, office automation apparatuses and the like.

Abstract: A process for treating a mixture of a polymer and a chlorinated organic solvent under heating, characterized by employing an apparatus in which a portion thereof to be brought into contact with the heated mixture is made of an acid resistant inorganic material selected from a group consisting of a metallic composition containing at least 85% of copper, nickel or a mixture thereof, and a ceramic material. Deterioration in color is improved in a process for recovering a polymer dissolved in the chlorinated organic solvent.

Abstract: A process for producing polycarbonate from a polycarbonate oligomer and a phenol compound, comprising introducing the oligomer, caustic alkali and the phenol compound in the first reaction zone where polymerization is carried out to produce polycarbonate having a viscosity average molecular weight of 3,000 to 15,000, and then introducing the reaction mixture containing the above polycarbonate into the second reaction zone where polymerization is carried out while controlling the alkali concentration to the range of 0.05 to 0.7N by regulating caustic alkali supplied.