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Continuous production of polycarbonates

  • US 3,945,969 A
  • Filed: 02/01/1974
  • Issued: 03/23/1976
  • Est. Priority Date: 02/02/1973
  • Status: Expired due to Term
First Claim
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1. A process for the continuous production of a high molecular weight polycarbonate by reaction of an organic dihydroxy compound selected from the group consisting of hydroquinone, resorcinol, pyrocatechol, 1,2-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 4,4'"'"'-dihydroxydiphenyl, 2,2'"'"'-dihydroxydiphenyl, 4,4'"'"'-dihydroxydiphenyl sulfide, 4,4'"'"'-dihydroxydiphenyl sulfoxide, 2,2'"'"'-dihydroxydiphenylsulfone, 4,4'"'"'-dihydroxydiphenyl-sulfone, 4,4'"'"'-dihydroxydiphenyl ether, 4,4'"'"'-dihydroxybenzophenone, 1,1-(4,4'"'"'-dihydroxydiphenyl)-1-phenylethane, 1,1-(4,4'"'"'-dihydroxydiphenyl)-cyclohexane, 4,4'"'"'-dihydroxydiphenylmethane and 2,2-(4,4'"'"'-dihydroxydiphenyl)-propane with phosgene in the presence of an amine or a salt of the same wherein the reaction is carried out in a plurality of reaction zones, a mixture of an aqueous-alkaline solution (a) of the organic compound and an aqueous solution of the amine or amine salt being introduced at the rate of from 1 to 50 meters per second and the phosgene (b) at the rate of from 30 to 300 meters per second in a first mixing and reaction zone, and condensed in said first mixing and reaction zone in a mainly aqueous alkaline solution to polycarbonate oligomers or polycarbonate, an organic solvent being introduced into said first mixing and reaction zone and incorporated into the mainly aqueous solution containing polycarbonate oligomers and polycarbonate at a point located in half removed from the inlet orifice for the aqueous-alkaline solution (a) and phosgene (b) or adjacent to the point of transition into the second reaction zone in such a way that back-mixing of the organic solvent containing polycarbonate oligomers or polycarbonate with the aqueous solution does not take place or only takes place to a trivial extent, and the condensation of the aqueous organic reaction mixture being carried to completion in a second reaction zone by the two-phase interfacial method.

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