Patent ID: 11859048
Assignee: SABIC GLOBAL TECHNOLOGIES B.V.
Field: Chemical engineering (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 14:
15. A method of melt polymerizing a polycarbonate, comprising:
adding a precursor solution comprising a polycarbonate precursor to 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, the reactor comprising:
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 that are each independently at an angle α from an orthogonal of the axis;
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,

wherein adding the precursor solution comprising the polycarbonate precursor to the reactor comprises adding the precursor solution comprising the polycarbonate precursor to the reactor through the reactant solution inlet;
mixing and polymerizing the polycarbonate precursor at the reactor temperature of 160 to 300° C., and the reactor pressure of 5 to 200 mbar to form a polycarbonate oligomer; and
withdrawing a mixed solution comprising the polycarbonate oligomer having a weight average molecular weight that is greater than that of the polycarbonate precursor from the reaction solution outlet.