Process for the manufacture of polycarbonate compositions

摘要

A continuous process for the manufacture of a polycarbonate comprises: combining an aromatic dihydroxy compound stream and a diaryl carbonate stream to form a mixture; controlling a weight or molar ratio of the diaryl carbonate to the aromatic dihydroxy compound by: measuring a sound velocity, Vs, in the mixture at an operating temperature of the controlling step; and determining the weight or molar ratio of the diaryl carbonate to the aromatic dihydroxy compound in the mixture; and adjusting a flow rate of at least one of the aromatic dihydroxy compound stream and the diaryl carbonate stream, if needed, to achieve a desired weight or molar ratio of the diaryl carbonate to the aromatic dihydroxy compound; and polymerizing the aromatic dihydroxy compound and the diaryl carbonate in the presence of a catalyst to produce the polycarbonate.

主权项

1. A process for monitoring a relative level of an aromatic dihydroxy compound or a diaryl carbonate in a mixture comprising the aromatic dihydroxy compound and the diaryl carbonate, the process comprising:
measuring a sound velocity, Vs, in the mixture at an operating temperature of the process; and determining the relative level of the aromatic dihydroxy compound or the diaryl carbonate in the mixture based on Equation 1, 2, 3 or 4:
WP1=a+b×Vs  (Equation 1)WP2=100−(a+b×Vs)  (Equation 2)WR=[100−(a+b×Vs)]/(a+b×Vs)  (Equation 3)MR=(Mw1/Mw2)×[100−(a+b×Vs)]/(a+b×Vs)  (Equation 4) wherein WP1 is the weight percent of the aromatic dihydroxy compound in the mixture, WP2 is the weight percent of the diaryl carbonate in the mixture, Mw1 is the molecular weight of the aromatic dihydroxy compound, Mw2 is the molecular weight of the diaryl carbonate, WR is the weight ratio of the diaryl carbonate to the aromatic dihydroxy compound, MR is the molar ratio of the diaryl carbonate to the aromatic dihydroxy compound, and a and b are constants.