Patent application number | Description | Published |
20100010252 | PROCESS FOR PREPARING DIARYL CARBONATES FROM DIALKYL CARBONATES - The invention provides a process for preparing diaryl carbonates from dialkyl carbonates and aromatic hydroxyl compounds using at least two reaction columns, a process section for recovering the dialkyl carbonate used in the reaction and for removing the alcohol of reaction, one or more process steps for removing the by-products obtained in the process which have a boiling point between that of the dialkyl carbonate and that of the alkyl aryl carbonate formed during the preparation of the diaryl carbonate, and a process step for further purification of the diaryl carbonate obtained from the reaction columns. | 01-14-2010 |
20100286431 | PROCESS FOR PREPARING DIARYL CARBONATE - A process for preparing diaryl carbonate and utilizing at least part of the process wastewater by increasing the concentration of the wastewater phases containing sodium chloride for the electrolysis by means of osmotic membrane distillation with simultaneous dilution of the sodium hydroxide solution obtained from the electrolysis for the diaryl carbonate production process (diphenyl carbonate process) is described. | 11-11-2010 |
20110009592 | PROCESS FOR THE PREPARATION OF POLYCARBONATE - A combined process for the preparation of polycarbonate from bisphenols and diaryl carbonates, the monophenol liberated being reacted again for the preparation of the diaryl carbonate and the alkali metal halide forming in the preparation of the diaryl carbonate being converted by electrochemical oxidation, optionally over a gas diffusion electrode, into chlorine and alkali hydroxide solution, the chlorine being recycled into the preparation of the phosgene and the alkali hydroxide solution being recycled into the preparation of the diaryl carbonate. | 01-13-2011 |
20110040117 | PROCESS FOR PREPARING DIALKYL CARBONATES FROM ALKYLENE CARBONATES AND ALCOHOLS - 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. | 02-17-2011 |
20110144371 | PROCESS FOR PURIFYING DIALKYL CARBONATES - 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. | 06-16-2011 |
20110184144 | PROCESS AND APPARATUS FOR THE PREPARATION OF POLYCARBONATE - The invention relates to a process for the pretreatment of material surfaces in order to minimize the interaction between polycarbonate and metal and, in the processing and synthesis of polycarbonate, to obtain a high-quality polymer which in particular does not become discoloured and is free of insoluble constituents. | 07-28-2011 |
20110237819 | PROCESS FOR PREPARING DIALKYL CARBONATES - The present invention relates to a continuous process for preparing lower dialkyl carbonates as main product and alkylene glycol as by-product by transesterification of a cyclic alkylene carbonate (e.g. ethylene carbonate or propylene carbonate) with lower alkyl alcohols in the presence of a catalyst and also the required purification of the dialkyl carbonate in a subsequent process step. To optimize the economics and energy efficiency of the process, additional devices are used for intermediate heating of the liquid streams in the apparatus. | 09-29-2011 |
20120101293 | PROCESS FOR CONTINUOUSLY PREPARING DIALKYL CARBONATE - The present invention relates to a continuous process for purifying a dialkyl carbonate/alkyl alcohol mixture in the preparation of dialkyl carbonate by catalysed transesterification of a cyclic alkylene carbonate (e.g. ethylene carbonate or propylene carbonate) with alkyl alcohols. For the increase in the product quality of the dialkyl carbonate, the selection of the operating parameters of the dialkyl carbonate purification column are crucial, in order to reduce the formation of unwanted by-products such as alkoxy alcohols and aliphatic carbonate ethers. | 04-26-2012 |
20120108782 | DEVICE AND METHOD FOR DEGASSING SOLVENT-CONTAINING POLYCARBONATE SOLUTIONS - The invention relates to an apparatus and a process for devolatilizing solvent-containing polycarbonate solutions. By employing the inventive apparatus, polycarbonates with low residual values of volatile constituents are produced from solvent-containing polymer melts, which improved optical properties, especially yellowness index, with the aid of an apparatus combination of a heatable tubular devolatilizer and a vented extruder. | 05-03-2012 |
20120123084 | DEVICE AND METHOD FOR DEGASSING SOLVENT-CONTAINING POLYCARBONATE SOLUTIONS - The invention relates to an apparatus and a process for devolatilizing solvent-containing polycarbonate solutions. By employing the inventive apparatus, polycarbonates with low residual values of volatile constituents are produced from solvent-containing polymer melts, which improved optical properties, especially yellowness index, with the aid of an apparatus combination of a flash devolatilizer and a vented extruder. | 05-17-2012 |
20120130110 | PROCESS FOR CONTINUOUSLY PREPARING DIALKYL CARBONATE - The present invention relates to a process comprising purifying dialkyl carbonates of the formula (II) in one or more columns in the presence of an alkylene oxide of the formula (V) and of an alkyl alcohol of the formula (IV) | 05-24-2012 |