Abstract: The present invention provides methods of producing high molecular weight polymer. A method of forming polycarbonate includes the step of combining in a reaction mixture a diaryl carbonate, a transesterification catalyst, an aliphatic dihydroxy compound, and a diacid compound in a reactor system. The temperature and pressure of the reactor system are adjusted to a first reactor setpoints and the reaction mixture is monitored to detect initiation of the exothermic oligomerization reaction. The reactor setpoint are adjusted to second reactor setpoints after detection of initiation of the exothermic oligomerization reaction. The reactor system is maintained at the second reactor setpoints to allow the reaction mixture to react to form an oligomer mixture.

Abstract: A method of forming polycarbonate includes the steps of introducing a plurality of reaction components to a reactor operating under melt polymerization conditions and removing ester-substituted phenol from the reactor. The plurality of reaction components include a dihydroxy compound, an ester-substituted diaryl carbonate, and a melt transesterification catalyst. The reaction components are introduced in a plurality of reaction component streams. A first reaction component streams includes a melt transesterification catalyst dissolved or suspended in a liquid carrier containing an ester-substituted phenol. The composition of the first reaction component stream is selected such that ester-substituted phenol is not generated as a reaction product in the first reaction component stream.