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 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.
摘要:
The invention is directed to new double metal cyanide (DMC) catalysts, a process for the preparation of these catalysts, and to a process for the preparation of polyetherpolyols by the polyaddition of alkylene oxides to starter compounds which contain active hydrogen atoms, wherein the catalyst comprises the novel double metal cyanide (DMC) catalyst of the present invention. These new double metal cyanide (DMC) catalysts comprise a) one or more double metal cyanide compounds, b) one or more organic complex ligands, and c) one or more cyclodextrins, with the proviso that b) and c) are different compounds. The catalysts of this invention exhibit greatly increased activity during preparation of a polyetherpolyol.
摘要:
The invention relates to novel zinc/metal hexacyanocobaltate complex compounds corresponding to the formula:Zn.sub.3-v M.sub.v [Co(CN).sub.6 ].sub.2.w(H.sub.2 O).x(L).y[Zn(X).sub.n ].z[M(Y).sub.m)].These complex compounds are suitable catalysts. This invention also relates to a process for the production of the compounds, and to the use of the compounds in a process for the production of polyether polyols.These novel zinc/metal hexacyanocobaltate complex compounds when used as catalysts in a process for the production of polyether polyols substantially reduce the induction period of the polyaddition reaction of alkylene oxides to starter compounds containing hydrogen atoms. Furthermore, the resultant polyether polyols have a significantly narrower molecular weight distribution.
摘要:
4-aminodiphenylamines are produced by hydrogenating nitrobenzene with hydrogen in the presence of bases containing hydroxide and/or oxide groups and heterogeneous catalysts and in the presence of inert aprotic solvents at temperatures of 0 to 200.degree. C. and pressures of 0.1 to 150 bars.