Bayer Aktiengesellschaft

Norbert Schon

Hans-Josef Buysch

Herbert Eichenauer

Paul Wagner

Steffen Kuhling

Pieter Ooms

Johann Rechner

Hans-Jurgen Kress

Josef Buekers

Karl-Heinz Ott

Alfred Pischtschan

Reinhard Langer

Edgar Leitz

Harald Blum

Wolfgang Ebert

Ulrich R Grigo

Rudolf Binsack

Lutz Schmalstieg

Wieland Hovestadt

Eberhard Zirngiebl

Gottfried Zaby

Wolfgang Jakob

Christine Mendoza-Frohn

Hartwig Hocker

Helmut Keul

Karl-Heinz Kohler

Ricarda Leiberich

Jurgen Kischkewitz

Dieter Rempel

Wolfgang Richter

Jurgen Dahmer

Alfred Jung

Hans-Erich Gasche

Eric Bischof

Stephan Kabelac

The present invention relates to a process for the continuous production of carbonates having aromatic ester groups by reacting aromatic hydroxy compounds with phosgene in the gas phase in the presence of heterogeneous catalysts.

Process for the continuous production of aryl carbonates

Described herein is a process for the preparation of 1,3-dioxan-2-one group-containing oligourethanes by reacting a) hydroxy-functional 1,3-dioxan-2-ones with b) compounds having an average of at least two isocyanate groups per molecule; the oligourethanes obtainable by this process; and their use, optionally in combination with compounds containing active hydrogen atoms, for the preparation of plastics or as a binder or binder component in coating compositions.

T,3-dioxan-2-one group-containing oligourethanes

Carbonates with aromatic ester groups can be produced by reaction of aromatic monohydroxy compounds with phosgene or with chloroformic acid esters of aromatic monohydroxy compounds, working at a temperature in the range of 50.degree. to 350.degree. C. in presence of oxides of the metals of Group IV B of the Mendeleeff periodic table as heterogeneous catalysts.

Process for the production of aryl carbonates

Organic carbonates which contain at least one aromatic ester group can be obtained continuously from carbonates, which contain at least one aliphatic ester group, and a phenolic compound in the presence of a transesterification catalyst known per se in that the reaction is carried out in a bubble column reactor or in a cascade of at least two bubble column reactors in such a way that the phenolic compound is metered into the first bubble column and the carbonate containing at least one aliphatic ester group is metered into each individual bubble column, but preferably only into the last bubble column. The carbonate containing at least one aromatic ester group is taken off in the liquid state from the last bubble column. Volatile reaction products, for example eliminated alcohol or a dialkyl carbonate are taken off at the upper end of each individual bubble column, preferably at the upper end of the first bubble column.

Process for the continuous preparation of aryl carbonates

This invention provides a process for the purification of diphenyl carbonate (DPC) from crude products of diphenyl carbonate production. In this process, crude products are used that have a distillable fraction consisting of over 70 wt. % diphenyl carbonate and are fractionally crystallised from the melt (fractionating melt crystallisation).

Process for the purification of diphenyl carbonate

Carbonates with aromatic ester groups may be prepared by reacting aromatic monohydroxy compounds with phosgene or with chloroformates of aromatic monohydroxy compounds, wherein the process is performed at a temperature in the range 50.degree.-350.degree. C. in the presence of aluminosilicates as heterogeneous catalysts.

Process for preparting aryl carbonates

Carbonates with aromatic ester groups may be prepared by reacting aromatic monohydroxy compounds with phosgene or with chloroformates of aromatic monohydroxy compounds, wherein reaction takes place at a temperature in the range 50.degree. to 350.degree. C. in the presence of aluminum oxides as heterogeneous catalysts.

Process for preparing aryl carbonates

Organic carbonates containing at least one aromatic ester group can be obtained in a continuous manner from carbonates containing at least one aliphatic ester group and a phenolic compound in the presence of a transesterification catalyst known per se by carrying out the reaction in at least two stirred containers connected one behind the other in such a way that, in each case, the phenolic compound is metered in liquid form into the first stirred container and the carbonate containing at least one aliphatic ester group is metered in liquid form into one or more of the stirred containers. The carbonate containing at least one aromatic ester group is removed in liquid form from the last stirred container. Volatile reaction products, for example alcohol which has been cleaved out or a dialkyl carbonate are removed in gaseous form from one or more stirred containers.

A continuous process for splitting an aromatic polycarbonate resin is disclosed. Accordingly there are reacted in a distillation column and in the presence of a catalyst (i) a polycarbonate resin in solution with (ii) methanol to produce a dihydroxy compound and dimethyl carbonate. The solution which contains polycarbonate and monohydroxy compound solvent exclusive of methanol is fed into the upper section of said column and the methanol is fed into the lower section of the column. The methanol is fed in the form of a mixture containing methanol and about 1-50 weight percent of dimethyl carbonate. The dimethyl carbonate thus produced is removed from an upper section of the column and the dihydroxy compound is removed from a lower section of the column.

Process for splitting polycarbonates

A process is disclosed for cleaving polycarbonates into bisphenols and diaryl carbonates by transesterifying with phenols in the presence of catalysts. The process entails isolating bisphenols from the product of the transesterification, and subjecting the remaining mixture which contains phenols and diaryl carbonates to flash distillation. The phenols and diaryl carbonates are distilled off and separated, and the diaryl carbonates are recovered.

Process for cleaving polycarbonates into bisphenols and diaryl carbonates

The title compounds are prepared from organic carbonates having at least one aliphatic ester group and phenolic compounds by transesterification in the presence of a transesterification catalyst known per se at 60.degree.-320.degree. C. in a column-type reactor with multiple recycling of the reaction products into this reactor with intermediate storage of the product streams.

Process for the preparation of organic carbonates having at least one

Carbonic diesters containing at least one aromatic ester group can be prepared from carbonic diesters containing at least one aliphatic ester group by transesterification using a phenol, titanium dioxide having a surface area of at least 20 m.sup.2 /g as determined by the BET method being used as catalyst.

Process for the preparation of aromatic carbonic diesters

Diaryl carbonates are prepared from dialkyl carbonates and phenolic compounds by transesterification in the presence of a transesterification catalyst at 60.degree.-320.degree. C. in an apparatus composed of two columns in a continuous procedure. In the first column, the starting materials form essentially the associated alkyl aryl carbonate, from which, in the second column, the diaryl carbonate is produced by further transesterification and disproportionation.

Process for the preparation of diaryl carbonates

Diaryl carbonates are prepared by reaction from dialkyl carbonates and phenols using conventional transesterification catalysts in a specific mass-coupled and energy-coupled combination of columns, for example according to FIG. 1, in which the reference numerals have the meaning specified in the description.

Process for the continuous preparation of diaryl carbonates from dialkyl

A process is described for preparing aromatic carbonates by transesterification of aliphatic carbonates with phenolic compounds in the presence of titanium compounds known per se, in which, before work-up, the transesterification mixture is cooled to a temperature below 120.degree. C., during which the mixture must remain liquid, the titanium-containing precipitate which is deposited is separated off, and the aromatic carbonate is then obtained by methods which are conventional per se.

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Krefeld, Germany

Norbert Schon