Abstract: In an embodiment, a reactor for carrying out a melt transesterification reaction at a reactor temperature of 160 to 300° C. and a reactor pressure of 5 to 200 mbar, comprises a cylindrical tank comprising a top, a side, and a bottom, wherein the bottom is convex, extending away from the top; a stirring shaft disposed within the cylindrical tank along an axis thereof so that it is rotatable from outside of the cylindrical tank; an impeller extending from the stirring shaft in the cylindrical tank and comprising a plurality of blades; a reactant solution inlet; a reaction solution outlet; and an externally located heat exchanger in fluid communication with the cylindrical tank via a recirculation stream and a heated stream. The reactor can be used for the polymerization of a polycarbonate oligomer.

Abstract: In an embodiment, a reactor for carrying out a melt transesterification reaction at a reactor temperature of 160 to 300° C. and a reactor pressure of 5 to 200 mbar, comprises a cylindrical tank comprising a top, a side, and a bottom, wherein the bottom is convex, extending away from the top; a stirring shaft disposed within the cylindrical tank along an axis thereof so that it is rotatable from outside of the cylindrical tank; a stirring blade extending from the stirring shaft in the cylindrical tank; a reactant solution inlet located on the bottom; and a reaction solution outlet located on the bottom. The reactor can be used for the polymerization of a polycarbonate oligomer.

Abstract: In an embodiment, a reactor for carrying out a melt transesterification reaction at a reactor temperature of 160 to 300° C. and a reactor pressure of 5 to 200 mbar, comprises a cylindrical tank comprising a top, a side, and a bottom, wherein the bottom is convex, extending away from the top; a stirring shaft disposed within the cylindrical tank along an axis thereof so that it is rotatable from outside of the cylindrical tank; a stirring blade extending from the stirring shaft in the cylindrical tank; a reactant solution inlet located on the bottom; and a reaction solution outlet located on the bottom. The reactor can be used for the polymerization of a polycarbonate oligomer.

Abstract: In an embodiment, a method of manufacture of a melt polycarbonate comprises melt polymerizing a bisphenol and diphenyl carbonate to form phenol and the melt polycarbonate in a polymerization unit; removing an overhead stream comprising the phenol in a gas phase from the polymerization unit; combining the overhead stream with a gas stream comprising a solvent in a gas phase to form a combined gas stream; wherein the combined gas stream has a freezing point at less than 3 mbar absolute that is less than the triple point of phenol; and condensing the combined gas stream in a condenser to form a condensed stream comprising the phenol and the solvent in a liquid phase.

Abstract: In an embodiment, a reactor for carrying out a melt transesterification reaction at a reactor temperature of 160 to 300° C. and a reactor pressure of 5 to 200 mbar, comprises a cylindrical tank comprising a top, a side, and a bottom, wherein the bottom is convex, extending away from the top; a stirring shaft disposed within the cylindrical tank along an axis thereof so that it is rotatable from outside of the cylindrical tank; a stirring blade extending from the stirring shaft in the cylindrical tank; a reactant solution inlet located on the bottom; and a reaction solution outlet located on the bottom. The reactor can be used for the polymerization of a polycarbonate oligomer.

Abstract: In an embodiment, a reactor for carrying out a melt transesterification reaction at a reactor temperature of 160 to 300° C. and a reactor pressure of 5 to 200 mbar, comprises a cylindrical tank comprising a top, a side, and a bottom, wherein the bottom is convex, extending away from the top; a stirring shaft disposed within the cylindrical tank along an axis thereof so that it is rotatable from outside of the cylindrical tank; an impeller extending from the stirring shaft in the cylindrical tank and comprising a plurality of blades; a reactant solution inlet; a reaction solution outlet; and an externally located heat exchanger in fluid communication with the cylindrical tank via a recirculation stream and a heated stream. The reactor can be used for the polymerization of a polycarbonate oligomer.

Abstract: A method for producing polycarbonate by melt polymerization can comprise: (a) adding acetone, diaryl carbonate, and dihydroxy compound to the melt polymerization unit, wherein the acetone is added to the melt polymerization unit as a mixture with the diaryl carbonate and/or the dihydroxy compound; (b) adding a catalyst to the melt polymerization unit, optionally without separating out acetone prior to the addition of the catalyst; and (c) operating the melt polymerization unit under conditions so that the diaryl carbonate(s) and dihydroxy compound(s); dihydroxy compound reacts with the diaryl carbonate to produce polycarbonate with a desired specification, and a phenol by-product.

Abstract: A method for producing polycarbonate by melt polymerization can comprise: (a) adding acetone, diaryl carbonate, and dihydroxy compound to the melt polymerization unit, wherein the acetone is added to the melt polymerization unit as a mixture with the diaryl carbonate and/or the dihydroxy compound; (b) adding a catalyst to the melt polymerization unit, optionally without separating out acetone prior to the addition of the catalyst; and (c) operating the melt polymerization unit under conditions so that the diaryl carbonate(s) and dihydroxy compound(s); dihydroxy compound reacts with the diaryl carbonate to produce polycarbonate with a desired specification, and a phenol by-product.