Abstract:
In an embodiment, a process of purifying a polycarbonate comprises: polymerizing a dihydroxy compound and a carbonate source via an interfacial reaction in the presence of a catalyst to form a product mixture comprising an aqueous phase and an organic phase, wherein the organic phase comprises the polycarbonate, the catalyst, ions, and a solvent having a boiling point Tb; heating the product mixture to greater than or equal to Tb; separating the aqueous phase and the organic phase at a temperature greater than or equal to Tb to form a separated organic phase and a separated aqueous phase; extracting the catalyst from the separated organic phase; and extracting the ions from the separated organic phase; wherein if a centrifuge is used in the extracting of the catalyst, the extracting of the ions, or both, the process further comprises cooling a stream entering the centrifuge to less than Tb.
Abstract:
In an embodiment, a process of purifying a polycarbonate from an interfacial polymerization product mixture comprising an aqueous phase and an organic phase comprising a first organic solvent, the polycarbonate, a catalyst, and ions, the process comprises: separating the aqueous phase and the organic phase to form a separated aqueous feed stream and a separated organic stream; extracting the catalyst and the ions from the separated organic stream to form a purified polycarbonate stream and an extracted aqueous feed stream, wherein at least one of the separated aqueous feed stream and the extracted aqueous feed stream comprise an organic portion and an aqueous portion; purifying an aqueous stream comprising one or both of the separated aqueous feed stream and the extracted aqueous feed stream by adjusting a viscosity of the organic portion to be less than or equal to 40 centipoise by adding a second organic solvent to the aqueous stream to form a combined stream; optionally, adjusting a ratio of the aqueous portion to the organic portion to 1.0 to 20.0 by adding an aqueous solution to the aqueous stream; and separating the combined stream to form a purified aqueous stream, wherein less than or equal to 3 vol % of the purified aqueous stream is the organic portion.
Abstract:
In another embodiment, a process of purifying an interfacially polymerized polycarbonate from a feed comprising an aqueous phase and an organic phase comprising an organic solvent, the interfacially polymerized polycarbonate, a catalyst, and ions, can comprise: separating the aqueous phase and the organic phase from the feed, wherein during the separating the feed is subjected to at least one of: energy of less than or equal to 0.5 kJ/kg of feed, a shear rate of less than 150,000 S−1, and centrifugal forces of 100 to 2,000 g-force; to form a purified aqueous phase and a purified organic phase comprising a purified polycarbonate.
Abstract:
In an embodiment, a process of purifying a polycarbonate from an interfacial polymerization product mixture comprising an aqueous phase and an organic phase comprising a first organic solvent, the polycarbonate, a catalyst, and ions, the process comprises: separating the aqueous phase and the organic phase to form a separated aqueous feed stream and a separated organic stream; extracting the catalyst and the ions from the separated organic stream to form a purified polycarbonate stream and an extracted aqueous feed stream, wherein at least one of the separated aqueous feed stream and the extracted aqueous feed stream comprise an organic portion and an aqueous portion; purifying an aqueous stream comprising one or both of the separated aqueous feed stream and the extracted aqueous feed stream by adjusting a viscosity of the organic portion to be less than or equal to 40 centipoise by adding a second organic solvent to the aqueous stream to form a combined stream; optionally, adjusting a ratio of the aqueous portion to the organic portion to 1.0 to 20.0 by adding an aqueous solution to the aqueous stream; and separating the combined stream to form a purified aqueous stream, wherein less than or equal to 3 vol % of the purified aqueous stream is the organic portion.
Abstract:
In an embodiment, a process of purifying a polycarbonate comprises: polymerizing a dihydroxy compound and a carbonate source via an interfacial reaction in the presence of a catalyst to form a product mixture comprising an aqueous phase and an organic phase, wherein the organic phase comprises the polycarbonate, the catalyst, ions, and a solvent having a boiling point Tb; heating the product mixture to greater than or equal to Tb; separating the aqueous phase and the organic phase at a temperature greater than or equal to Tb to form a separated organic phase and a separated aqueous phase; extracting the catalyst from the separated organic phase; and extracting the ions from the separated organic phase; wherein if a centrifuge is used in the extracting of the catalyst, the extracting of the ions, or both, the process further comprises cooling a stream entering the centrifuge to less than Tb.
Abstract:
In another embodiment, a process of purifying an interfacially polymerized polycarbonate from a feed comprising an aqueous phase and an organic phase comprising an organic solvent, the interfacially polymerized polycarbonate, a catalyst, and ions, can comprise: separating the aqueous phase and the organic phase from the feed, wherein during the separating the feed is subjected to at least one of: energy of less than or equal to 0.5 kJ/kg of feed, a shear rate of less than 150,000 S−1, and centrifugal forces of 100 to 2,000 g-force; to form a purified aqueous phase and a purified organic phase comprising a purified polycarbonate.