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 provides new double metal cyanide (DMC) catalysts for preparing polyetherpolyols by the polyaddition of alkylene oxides to starter compounds which contain active hydrogen atoms, wherein the catalyst comprises a) double metal cyanide compounds, b) bile acids or their salts, esters or amides and c) organic complex ligands. The catalysts according to the invention show greatly increased activity during preparation of a polyetherpolyol.
摘要:
The present invention relates to novel double metal cyanide (DMC) catalysts for the preparation of polyether polyols by a polyaddition reaction between alkylene oxides and starter compounds having active hydrogen atoms, wherein the catalyst contains a) at least one double metal cyanide compound, b) at least one organic complexing ligand and c) at least one fluorine-containing complexing ligand.
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.
摘要:
The invention relates to novel double metal cyanide (DMC) catalysts for the preparation of polyether polyols by polyaddition of alkylene oxides to starter compounds containing active hydrogen atoms, wherein the catalyst contains a) double metal cyanide compounds, b) organic complex ligands other than c), and c) carboxylic acid ester of polyhydric alcohols. The catalysts according to the invention have greatly increased activity in the preparation of polyether polyols.
摘要:
This invention relates to new double metal cyanide (DMC) catalysts, a process for the preparation of these DMC catalysts, and to a process for the production of polyether polyols by the polyaddition of alkylene oxides to starter compounds which comprise active hydrogen atoms, wherein the catalyst comprises a) one or more double metal cyanide compounds, b) one or more organic complexing ligands, and c) one or more organic phosphates, organic phosphites, organic phosphonates, organic phosphonites, organic phosphinates or organic phosphinites. The catalysts according to the invention exhibit a considerably increased activity for polyether polyol production.