Abstract: Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus. The alkyl chloroformate may be decomposed by passing it through a passageway at a temperature of about 30° C. to about 130° C. for a time of about 0.5 hour to about 10 hours. The passageway may include one or more holding vessels or a tubular section that promotes plug flow.

Abstract: Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus.

Abstract: A method of making polycarbonates comprises melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester in a presence of a polymerization catalyst in a reactor system producing a byproduct stream, wherein the polymerization catalyst comprises a quaternary phosphonium compound; and purifying the byproduct stream to separate phenol, wherein the separated phenol has a phosphorus concentration of less than or equal to about 3 part per million, based upon the total weight of the phenol separated.

Abstract: A method of making polycarbonate comprises melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester in a presence of a polymerization catalyst in a reactor system producing a byproduct stream, wherein the polymerization catalyst comprises a quaternary phosphonium compound; and purifying the byproduct stream to separate the carbonic acid diester, wherein the separated carbonic acid diester has a phosphorous concentration of less than or equal to about 30 parts per million.

Abstract: A method and apparatus for continuously producing an alkyl aryl ether and a diaryl carbonate by reacting a dialkyl carbonate and an aromatic alcohol in presence of a transesterification catalyst.

Abstract: The present invention relates to a method of preparing polycarbonate comprising the steps of: (i) introducing to an extruder through a feed port a plurality of reaction components comprising a polycarbonate oligomer, an activated carbonate residue, and a transesterification catalyst, wherein the extruder comprises the feed port, a first back vent port, and a polycarbonate exit port, wherein the feed port is located between the first back vent port and the polycarbonate exit port, and wherein the resistance to flow of the reaction components from the feed port to the first back vent port is less than or equal to the resistance to flow of the reaction components from the feed port to the polycarbonate exit port; and (ii) extruding the reaction components at one or more temperatures in a range between 100° C. and 400° C., wherein during the extrusion of the reaction components, activated carbonate residue is removed through the first back vent port, thereby preparing a polycarbonate.

Abstract: The present invention provides a method of making polycarbonate oligomers, polycarbonate, molded articles formed from polycarbonate, and an apparatus for making polycarbonate. An oligomer mixture is first prepared by the steps of providing an equilibration system comprising a vessel, a reaction mixture contained within the vessel, and means for mixing the reaction mixture contained within the vessel wherein the reaction mixture comprises a melted activated diaryl carbonate composition, and a catalyst present in sufficient amount to initiate an oligomerization reaction between a dihydroxy composition and the activated diaryl carbonate to form polycarbonate oligomers.

Abstract: A method of making polycarbonate comprises melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester in a presence of a polymerization catalyst in a reactor system producing a byproduct stream, wherein the polymerization catalyst comprises a quaternary phosphonium compound; and purifying the byproduct stream to separate the carbonic acid diester, wherein the separated carbonic acid diester has a phosphorous concentration of less than or equal to about 30 parts per million.

Abstract: A method of making polycarbonates comprises melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester in a presence of a polymerization catalyst in a reactor system producing a byproduct stream, wherein the polymerization catalyst comprises a quaternary phosphonium compound; and purifying the byproduct stream to separate phenol, wherein the separated phenol has a phosphorus concentration of less than or equal to about 3 part per million, based upon the total weight of the phenol separated.

Abstract: The present invention relates to a method of preparing polycarbonate comprising the steps of: (i) introducing to an extruder through a feed port a plurality of reaction components comprising a polycarbonate oligomer, an activated carbonate residue, and a transesterification catalyst, wherein the extruder comprises the feed port, a first back vent port, and a polycarbonate exit port, wherein the feed port is located between the first back vent port and the polycarbonate exit port, and wherein the resistance to flow of the reaction components from the feed port to the first back vent port is less than or equal to the resistance to flow of the reaction components from the feed port to the polycarbonate exit port; and (ii) extruding the reaction components at one or more temperatures in a range between 100° C. and 400° C., wherein during the extrusion of the reaction components, activated carbonate residue is removed through the first back vent port, thereby preparing a polycarbonate.

Abstract: The present invention provides a method of making polycarbonate oligomers, polycarbonate, molded articles formed from polycarbonate, and an apparatus for making polycarbonate. An oligomer mixture is first prepared by the steps of providing an equilibration system comprising a vessel, a reaction mixture contained within the vessel, and means for mixing the reaction mixture contained within the vessel wherein the reaction mixture comprises a melted activated diaryl carbonate composition, and a catalyst present in sufficient amount to initiate an oligomerization reaction between a dihydroxy composition and the activated diaryl carbonate to form polycarbonate oligomers.

Abstract: Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus.

Abstract: Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus. The alkyl chloroformate may be decomposed by passing it through a passageway at a temperature of about 30 C to about 130° C. for a time of about 0.5 hour to about 10 hours. The passageway may include one or more holding vessels or a tubular section that promotes plug flow.

Abstract: Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus. The alkyl chloroformate may be decomposed by passing it through a passageway at a temperature of about 30° C. to about 130° C. for a time of about 0.5 hour to about 10 hours. The passageway may include one or more holding vessels or a tubular section that promotes plug flow.

Abstract: A method and apparatus for continuously producing an alkyl aryl ether and a diaryl carbonate by reacting a dialkyl carbonate and an aromatic alcohol in presence of a transesterification catalyst.

Abstract: This invention relates to an extrusion method preparing polycarbonates from a solution of an oligomeric polycarbonate. A mixture of bis(methyl salicyl)carbonate (BMSC), BPA and a transesterification catalyst are first equilibrated at moderate temperatures to provide a solution of polycarbonate oligomer in methyl salicylate. The solution is then fed to a devolatilizing extruder, where the polymerization reaction is completed and the methyl salicylate solvent is removed. The solution comprising the oligomeric polycarbonate can also be pre-heated under pressure to a temperature above the boiling point of methyl salicylate and subsequently fed to a devolatilizing extruder equipped for rapid flashing off the solvent. The method provides polycarbonate with greater efficiency than the corresponding process in which unreacted monomers are fed to the extruder. Additionally, the method of the invention does not require the isolation of a precursor polycarbonate comprising ester-substituted phenoxy terminal groups.

Abstract: This invention relates to an extrusion method preparing polycarbonates from a solution of an oligomeric polycarbonate. A mixture of bis(methyl salicyl)carbonate (BMSC), BPA and a transesterification catalyst are first equilibrated at moderate temperatures to provide a solution of polycarbonate oligomer in methyl salicylate. The solution is then fed to a devolatilizing extruder, where the polymerization reaction is completed and the methyl salicylate solvent is removed. The solution comprising the oligomeric polycarbonate can also be pre-heated under pressure to a temperature above the boiling point of methyl salicylate and subsequently fed to a devolatilizing extruder equipped for rapid flashing off the solvent. The method provides polycarbonate with greater efficiency than the corresponding process in which unreacted monomers are fed to the extruder. Additionally, the method of the invention does not require the isolation of a precursor polycarbonate comprising ester-substituted phenoxy terminal groups.

Abstract: Unexpected corrosion of downstream sections of a dialkyl carbonate manufacturing apparatus has been traced to alkyl chloroformate impurities, which slowly decompose to yield hydrochloric acid. An improved process and apparatus for dialkyl carbonate synthesis reduce corrosion by physically removing or chemically decomposing the alkyl chloroformate impurities within the corrosion-resistant upstream sections of the apparatus. The alkyl chloroformate may be decomposed by passing it through a passageway at a temperature of about 30° C. to about 130° C. for a time of about 0.5 hour to about 10 hours. The passageway may include one or more holding vessels or a tubular section that promotes plug flow.

Abstract: Polycarbonates having a high level of endcapping and containing a low level of Fries rearrangement product are prepared from dihydroxy aromatic compounds, such as bisphenol A, and diaryl carbonates such as diphenyl carbonate in a two stage process involving a tetraalkyl phosphonium carboxylate catalyzed oligomerization of the reactants in a first reaction stage followed by the addition of an alkali metal hydroxide co-catalyst in the second stage of the polymerization reaction. The late addition of the co-catalyst provides improved polymerization reaction rates as judged by higher polycarbonate molecular weights. The amount of alkali metal hydroxide co-catalyst is small thus avoiding the formation of excessive amounts of Fries product. The method has been used to provide Fries product levels between 200 and 800 parts per million in polycarbonates having Mn values between 7,500 and 8,500 Daltons.

Abstract: This invention relates to an extrusion method preparing polycarbonates from a solution of an oligomeric polycarbonate. A mixture of bis(methyl salicyl)carbonate (BMSC), BPA and a transesterification catalyst are first equilibrated at moderate temperatures to provide a solution of polycarbonate oligomer in methyl salicylate. The solution is then fed to a devolatilizing extruder, where the polymerization reaction is completed and the methyl salicylate solvent is removed. The solution comprising the oligomeric polycarbonate can also be pre-heated under pressure to a temperature above the boiling point of methyl salicylate and subsequently fed to a devolatilizing extruder equipped for rapid flashing off the solvent. The method provides polycarbonate with greater efficiency than the corresponding process in which unreacted monomers are fed to the extruder. Additionally, the method of the invention does not require the isolation of a precursor polycarbonate comprising ester-substituted phenoxy terminal groups.