Abstract: 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).

Abstract: Ethylene glycol carbonate (EGC) can be obtained in purified form from contaminated material which contains impurities from the production or work-up process, by subjecting it to treatment with activated carbon. The treatment is carried out at 40.degree.-250.degree. C. and at 1-200 bar. The activated carbon has a BET surface area of 200-3,000 m.sup.2 /g.

Abstract: The invention relates to a process for the production of carbonic acid esters of polysaccharides which is characterized in that polysaccharides are reacted with carbonic acid esters.

Abstract: Reactors are described for the continuous reaction of gaseous substances on fixed bed catalysts with continuous temperature control and with the aid of a heat transport medium. These reactors are characterised by the design of the catalyst bed in the form of one or more regularly shaped sheet-like layers having a thickness of 0.01-50 cm, the surface of the catalyst layers being covered by a gas-permeable layer and this surface, on the starting material intake side and/or on the product outlet side, facing a likewise regularly shaped wall at a distance of 0.1 to 10 cm, which wall separates the space for the substances to be reacted or reacted substances from the space for the heat transport medium. The reactors are further characterised by the substances to be reacted being directed so as to flow through the catalyst bed approximately or completely perpendicularly to the sheet-like catalyst layers.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: New polysaccharides have recurring units I or a salt thereof.

Abstract: A process is described for the catalytic preparation of propylene glycol carbonate (PGC) by reacting propylene oxide (POX) and CO.sub.2 in PGC as reaction medium at elevated temperature and elevated pressure and separating off from the catalyst the PGC formed. The process is carried out continuously under adiabatic temperature conditions. Per unit of time, PGC as reaction medium flows into the reactor at 7 to 350 times the amount of the PGC formed per unit of time. At all points of the reactor a CO.sub.2 excess is maintained over the other reaction partner POX. Of the effluent reaction mixture, 80 to 98% by weight are returned to the entrance of the reactor, while the remainder is worked up to give PGC. The sensible heat of the reaction product resulting from the adiabatic temperature conditions can be used for the work-up.

Abstract: 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) methanolto 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.

Abstract: A process for purifying aromatic carbonate polymers, including polycarbonates and polyestercarbonates, is disclosed. Accordingly a carbonate polymer in an organic solvent is rendered virtually free of low molecular weight components by agitation with aluminosilicate or by passing through layers of such aluminosilicate. The aluminosilicate is subsequently separated off and the carbonate polymer is isolated in known methods.

Abstract: The present invention provides blends of polycarbonates and triphenylphosphane sulphonates and optionally fluorinated polyolefins and/or further customary additives, together with a process for the production of the blends according to the invention.

Abstract: In the hydrogenation of phenol with H.sub.2 over Pd supported catalysts, the ratio of the products formed, cyclohexanone and cyclohexanol, can be predetermined by specific treatment of the catalysts during the initial activation and regeneration by O.sub.2 pretreatment and H.sub.2 treatment, the following time/temperature conditions being used:a) Cyclohexanone:cyclohexanol=85:15 to 98:2a1) for initial activation, no O.sub.2 pretreatment and H.sub.2 treatment for 50-10 hours at 300.degree.-500.degree. C.;a2) for regeneration, O.sub.2 pretreatment for 30-0.5 hours at 220.degree.-380.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.degree. C.;b) Cyclohexanone:cyclohexanol=30:70 to below 85:15b1) for initial activation, O.sub.2 pretreatment for 40-3 hours at 250.degree.-500.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.degree. C.;b2) for regeneration, O.sub.2 pretreatment for 30-0.5 hours at 380.degree.-600.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.

Abstract: Alkylene carbonates can be prepared by catalytic reaction of alkylene oxides with carbon dioxide, catalysts which can be regenerated of the formulaa[MX]/b[ZnY.sub.2 ] (III)whereinM denotes an alkali metal,X and Y independently of one another denote chlorine, bromine or iodine anda and b denote fractions or integers in a range from 0.001 to 2being employed.The catalysts (III) can be regenerated by treating with a halogen compound. The halogen compounds which can be used for this purpose belong to the group comprising hydrogen halides, inorganic and organic acid halides, interhalogen compounds and organic halides with mobile halogen.

Abstract: 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.

Abstract: Mixtures of m- and p-dichlorobenzene can be separated by treating such mixtures in the liquid phase with a pentasil zeolite at from 20.degree. to 250.degree. C., a filtrate enriched in m-dichlorobenzene being removed and the p-dichlorobenzene being obtained by desorption of the pentasil zeolite. The pentasil zeolites may contain, as exchangeable cations, protons, cations of the first or second main group of the Mendeleev Periodic System, cations of the rare earth metals or a mixture of a plurality thereof. In order to prepare the liquid phase a solvent is used that belongs to the group of cyclic saturated hydrocarbons having 5 to 15 carbon atoms, alkyl-substituted aromatic hydrocarbons having 8 to 12 carbon atoms, and halogen-substituted aromatic hydrocarbons having 6 to 10 carbon atoms and 1 to 3 halogen atoms. The solvents ethylbenzene, chlorobenzene, p-xylene, p-chlorotoluene and dichlorobenzene are excepted. A mixture of a plurality of these solvents may also be used.

Abstract: Cyclohexylamine and dicyclohexylamine can be prepared as a mixture with one another by reaction of phenol with aniline, ammonia or a mixture of aniline and ammonia in the presence of hydrogen over a catalyst, the reaction being carried out according to the invention over a palladium catalyst which has a support of niobic acid or tantalic acid or a mixture of niobic acid and tantalic acid or a support containing such acids. The reaction is carried out at 100.degree.-220.degree. C. under an H.sub.2 partial pressure of 0.5-500 bar.

Abstract: 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.

Abstract: Di-(C.sub.1 -C.sub.4 -alkyl) carbonates can be prepared by catalysed counter-current reesterification of ethylene glycol carbonate or propylene glycol carbonate with a C.sub.1 -C.sub.4 -alcohol in a column, ethylene glycol carbonate or propylene glycol carbonate being introduced into the upper part of the column and a dialkyl carbonate-containing C.sub.1 -C.sub.4 -alcohol being introduced into the central or lower part of the column and pure alcohol being additionally introduced below the introduction of the dialkyl carbonate-containing alcohol.

Abstract: 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.