Abstract: A process for the synthesis of polycarbonate is disclosed. The process entails reacting in the presence of at least one phosphonium salt as catalyst, at least one diphenol, at least one carbonic acid diester, and at least one alkyl group-substituted phenol chain terminator. The chain terminator is introduced in free form or as a transesterifiable compound under the conditions of the synthesis. The polycarbonate thus produced is suitable for preparing a variety of molded articles.

Abstract: A process for making a high molecular weight (co)polycarbonate resin is disclosed. The process entails (i) obtaining at least one member selected from the group low molecular weight residue (weight average molecular weight 15,000 to 30,000) of aromatic (co)polycarbonate production, waste of (co)polycarbonate production, remainders of (co)polycarbonate production and (co)polycarbonate recyclate (ii) melting the said member in a suitable vessel to obtain a melt and (iii) feeding the melt into a reactor optionally along with at least one bisphenol or oligocarbonate having terminal OH groups and further optionally with a transesterification catalyst, and (iv) subjecting the melt to transesterification reaction at a temperature of 250 to 350° C., at a pressure below 5 mbar and residence time of 0.02-4 hours.

Abstract: A melt-polymerized polycarbonate is disclosed.

Abstract: The invention relates to a method for producing phosphonium phenolates from phosphonium halogenides and phenols.

Abstract: A branched melt-polymerized polycarbonate having pronounced non-Newtonian flow behavior is disclosed. The polycarbonate is suitable for preparing molding compositions and the preparation of a variety of molded articles.

Abstract: A process for producing polycarbonate is disclosed. The process entails obtaining an oligocarbonate produced by transesterification of diaryl carbonate with dihydroxyaryl compound in the presence of catalysts and introducing the oliogocarbonate into a reactor that enables continuous formation of free films at a rate higher than 10. The reactor including a horizontal cylinder equipped with a heating jacket, at least one vapor outlet, a feed nozzle an outlet nozzle, a rotatable cylindrical basket having a cylindrical perforated wall and annular discs positioned at intervals around the periphery of said basket and along the length thereof, and means for rotating said basket, the interior of said basket including no central shaft, the diameter of the cylindrical basket corresponding to about ⅔ of the diameter of the horizontal cylinder, and said discs being formed of perforated sheet metal.

Abstract: A continuous process for producing polycarbonates by the transesterification of didiaryl carbonates with dihydroxyaryl compounds in the presence of quaternary onium compounds is disclosed. The polycarbonates thus produced are suitable for preparing a variety of articles.

Abstract: A process for preparing phosphonium phenolate is disclosed. The process entails a reaction of phosphonium halide with phenol in an aqueous alkaline solution at a temperature of 0 to 55° C. The molar ratio of phenol to phosphonium halide is between 2:1 to 10:1 and the pH of the solution is 9.5 to 11. An optional embodiment entails carrying out the reaction in the further presence of alcohol.

Abstract: A continuous process for producing oligocarbonate is disclosed. The process entails in sequence the steps of a) reacting a dihydroxyaryl compound with a diaryl carbonate in the presence of a catalyst to obtain a melt and avoiding removal of released monohydroxyaryl compound and b) withdrawing the monohydroxyaryl compound by flash evaporation and c) heating the melt obtained under vacuum in an evaporator equipped with sump receiver and d) repeating at least once steps b) and then c) each at gradually increased temperatures and lowered pressures.

Abstract: An improvement to the melt transesterification reaction of diaryl carbonate with dihydroxy aryl compound is disclosed.

Abstract: An apparatus for the spectroscopic analysis of the composition of the contents of vessels, especially of conduits, by recording transmission spectra is described. The apparatus comprises at least a radiation source for generating the measuring radiation, and a spectral analyzer for measuring the transmitted radiation, two windows which are disposed opposite one another on the vessel and are transparent to the measuring radiation, and two collimators which are designed to spread the measuring radiation within the range of the measuring section and are disposed opposite one another in front of the windows, characterized in that the collimators are positioned relative to one another in a mounting joined to the vessel and the collimators can, while their relative alignment is maintained, be swung out in parallel from the range of the measuring section in the vessel or be displaced and/or be fixed to the mounting, so that the measuring section bypasses the vessel.

Abstract: A process of producing branched polycarbonates by melt transesterification from at least one diphenol, diaryl carbonate and a branching agent, and in the optional presence of a catalyst is disclosed. The process which is carried out at temperatures between 80 to 400° C. and at pressures between 1 and 0.01 mbar, entails using as branching agent at least one member selected from the group consisting of (i) a specifically structured aliphatic alcohol and (ii) the ether of (i) which is formed by self-condensation.

Abstract: The present invention relates to a transesterification method for producing solvent-free polycarbonate, using N-alkyl-substituted piperidines or N-alkyl-substituted morpholines comprising C2-C12 N-alkyl substituents, preferably C2-C8 N-alkyl substituents, most preferably C2-C5 N-alkyl substituents, as catalysts.

Abstract: A process for preparing phosphonium phenolate is disclosed. The process entails a reaction of phosphonium halide with phenol in an aqueous alkaline solution at a temperature of 0 to 55° C. The molar ratio of phenol to phosphonium halide is between 2:1 to 10:1 and the pH of the solution is 9.5 to 11. An optional embodiment entails carrying out the reaction in the further presence of alcohol.

Abstract: The invention relates to a two-step melt process for the production of thermoplastic, solvent-free, low-branching polycarbonates with low --OH terminal group content using a self-cleaning high-viscosity reactor.

Abstract: The present invention relates to a transesterification process for producing thermoplastic polycarbonates with the use of fixed bed catalysts.

Abstract: The invention relates to a transesterification process for the production of thermoplastic, solventless oligo-/polycarbonates in which aromatic diphenols and carbonic acid diaryl esters are combined and reacted in gaseous form.

Abstract: The present invention provides a two-stage melt process for the manufacture of thermoplastic, solvent-free, low-branched polycarbonates with low OH end-group contents with the use of ammonium or phophonium catalysts in the first stage and alkali and alkaline earth catalysts in the second stage.

Abstract: The present invention provides a melt process for the manufacture of thermoplastic solvent-free polycarbonates with the use of a continuously operated tubular reactor for monophenol vaporization.

Abstract: The present invention relates to a process for the preparation of polycarbonates in which an oil-in-water emulsion is maintained throughout by employing special reaction conditions.