C - Chemistry – Metallurgy – 08 – G
Patent
C - Chemistry, Metallurgy
08
G
C08G 64/10 (2006.01) C08G 64/20 (2006.01) C08G 64/38 (2006.01)
Patent
CA 2092286
2092286 9303083 PCTABS00019 A process for preparing halogenated polycarbonate wherein the total amount of base, the end pH of the aqueous phase, and the amount of coupling catalyst employed in the reaction are controlled to selected levels. In one embodiment, carbonate oligomers are condensed to form polycarbonate by contacting said oligomers in a tank reactor with an (i) organic solvent; (ii) 50 weight parts per million or less of coupling catalyst, based on the weight of all organic solvent employed in the oligomer formation and condensation steps, including any in which the coupling catalyst may be dissolved; and (iii) an amount of base which, together with the amount of base employed in the oligomer formation step, brings the total moles of base employed in the oligomer formation and condensation steps per mole of dihydroxy compound to the number given by 2 + 4(Y-1) + Q, where Y is the number of moles of carbonate precursor per mole of dihydroxy compound, and Q is about 0.001 to about 0.2. In another embodiment, carbonate oligomers are condensed to form polycarbonate by contacting said oligomers in a tubular reactor with an (i) organic solvent; (ii) 150 weight parts per million or less of coupling catalyst, based on the weight of all organic solvent employed in the oligomer formation and condensation steps, including any in which the coupling catalyst may be dissolved; and (iii) an amount of base which, together with the amount of base employed in the oligomer formation step, brings the total moles of base employed in the oligomer formation and condensation steps per mole of dihydroxy compound to the number given by 2 + 4(Y-1) + Q, where Y is the number of moles of carbonate precursor per mole of dihydroxy compound, and Q is about 0.001 to about 0.5. The process yields a halogenated polycarbonate of desirably high weight molecular weight, for example in excess of 80,000.
Cummings Clark J.
Kao Che-I
Munjal Sarat
Smart & Biggar
The Dow Chemical Company
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