摘要:
The present invention relates to a process for the continuous preparation of diaryl carbonates from phosgene and at least one monohydroxy compound (monophenol) in the presence of catalysts, and also the use thereof for preparing polycarbonates. The hydrogen chloride formed in the reaction is converted by thermal oxidation into chlorine, with the chlorine being recirculated to the preparation of phosgene. In particular, the process comprises utilization of the hydrogen chloride formed for the process for preparing diphenyl carbonate (DPC process).
摘要:
The invention relates to a process for preparing diaryl carbonates and/or alkyl aryl carbonates from dialkyl carbonates and aromatic hydroxy compounds using a reactive dividing wall column.
摘要:
The invention relates to a process for production of diaryl carbonate combined with the electrolysis of the resultant alkali metal chloride-containing process wastewater. The process according to the invention makes possible, inter alia, improved utilization in electrolysis of the alkali metal chloride-containing solution obtained in the production of diaryl carbonate.
摘要:
Disclosed are random copoly(phosphonate carbonate)s with the high molecular weight and narrow molecular weight distribution exhibiting a superior combination of properties compared to prior art.
摘要:
The present invention relates to a process for the continuous preparation of diaryl carbonates from phosgene and at least one monohydroxy compound (monophenol) in the presence of catalysts, and also the use thereof for preparing polycarbonates. The hydrogen chloride formed in the reaction is converted by electrochemical oxidation into chlorine, with the chlorine being recirculated to the preparation of phosgene. In particular, the process comprises utilization of the hydrogen chloride formed for the process for preparing diphenyl carbonate (DPC process).
摘要:
Processes comprising: reacting a dialkyl carbonate and an aromatic hydroxy compound in the presence of a transesterification catalyst in a first reaction column, the first reaction column comprising a top section, a bottom section, a rectifying section in an upper portion of the column and a reaction zone below the rectifying section; feeding a bottom product from the first reaction column to a further reaction column; the bottom product comprising a diaryl carbonate, an alkylaryl carbonate, or both, and residual unreacted dialkyl carbonate and aromatic hydroxy compound; the further reaction column comprising a top section, a rectifying section in an upper portion of the column and a reaction zone below the rectifying section; and reacting the residual unreacted dialkyl carbonate and aromatic hydroxy compound in the further reaction column; feeding a process stream to a distillation column, the process stream comprising a mixture of unreacted dialkyl carbonate and one or more reaction-product alcohols drawn from the first reaction column, the further reaction column, or both, such that the unreacted dialkyl carbonate is separated from the one or more reaction-product alcohols; and recycling the separated, unreacted dialkyl carbonate to the first reaction column; wherein the further reaction column comprises one or more condensers, and heat of condensation from the one or more condensers is fed back into the process.
摘要:
The present invention relates to a special process for purifying dialkyl carbonates. In particular, the present invention relates to a continuous process for purifying a dialkyl carbonate/alcohol-mixture in the preparation of lower dialkyl carbonate by catalysed transesterification of a cyclic alkylene carbonate (e.g. ethylene carbonate or propylene carbonate) with lower alcohols. To optimize the economics and energy efficiency of the process, an apparatus for intermediate heating of the internal liquid stream is used.
摘要:
The present invention relates to a continuous process for preparing lower dialkyl carbonates as main product and alkylene glycol as by-product by catalyzed transesterification of a cyclic alkylene carbonate (e.g. ethylene carbonate or propylene carbonate) with lower alcohols, where the reaction of the alkylene carbonate is carried out with an alcohol containing dialkyl carbonate in countercurrent, characterized in that introduction of a stream containing at least 99.5% by weight of alcohol takes place below the point of introduction for the alcohol containing dialkyl carbonate in a particular spacing ratio between the abovementioned points of introduction.
摘要:
Processes comprising: transesterifying a dialkyl carbonate and an aromatic hydroxyl compound in the presence of a transesterification catalyst to provide a diaryl carbonate product comprising the transesterification catalyst as an impurity; subjecting the diaryl carbonate product to distillation in a first distillation column having an upper part and a lower part, wherein the upper part comprises a rectifying section and the lower part comprises a stripping section; and withdrawing a first sidestream from the first distillation column, wherein the first sidestream comprises a purified diaryl carbonate.
摘要:
The invention relates to the preparation of hydroxybenzoic benzyl esters by reacting benzyl chloride with hydroxybenzoic acids in the presence of one or more amides.