Abstract: 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.

Abstract: The present invention relates to a process for the continuous production of carbonates having aromatic ester groups by the reaction of aromatic hydroxy compounds with phosgene in the presence of heterogeneous catalysts, phosgene still present being removed from the stream of waste gas by returning the waste gas to an additional reactor.

Abstract: Aromatic amines are produced by hydrogenation of the appropriate aromatic nitro compounds in the vapour phase on fixed catalysts. The catalysts contain supported metals active in hydrogenation, the reaction is carried out under adiabatic conditions at a pressure of from 1 to 30 bar, an inlet temperature of from 200.degree. to 400.degree. C. and a maximum catalyst temperature of 500.degree. C.

Abstract: The invention relates to a process for the preparation of carbonates having a six-membered ring, of the formula ##STR1## by transesterification of 1,3-propanediol compounds with carbonic acid esters and subsequent distillative depolymerization of the oligo- or polycarbonate initially formed, one or more catalysts from the group consisting of compounds of Sn, Ti or Zr being employed both for the transesterification and for the depolymerization and, if appropriate, the distillation residue is at least partly recycled into the transesterification. Such carbonates having a six-membered ring can furthermore be stabilized against undesirable polymerization by addition of small amounts of acids of sulfur or phosphorus or esters or salts thereof.

Abstract: The present invention relates to a process for producing diaryl carbonates by the reaction of an aromatic hydroxy compound (e.g. phenol) with carbon monoxide and oxygen in the presence of a catalyst, a co-catalyst, a quaternary salt and a base, which is characterised in that the reaction is conducted in a melt comprising the diaryl carbonate and the hydroxy compound on which the carbonate is based, and further diaryl carbonate is optionally added to this reaction mixture before work-up.

Abstract: Carbazole can be prepared by dehydrogenation of compounds of the formula ##STR1## or by aminating dehydrogenation of compounds of the formula ##STR2## at 300.degree. to 600.degree. C. in the presence of hydrogen over an iridium catalyst or an iridium-containing catalyst.

Abstract: 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.

Abstract: Catalyst systems with a content of a platinum-group-metal catalyst, a co-catalyst, a quaternary salt and a base for the oxidative carbonylation of aromatic hydroxy compounds to the corresponding diaryl carbonates are obtained according to the invention as a residual melt by melt crystallization and can be returned into the carbonylation reaction or worked up to valuable materials. The melt crystallizate, which consists predominantly of diaryl carbonate and the parent aromatic hydroxy compound, is worked up to pure diaryl carbonate and pure hydroxy compound.

Abstract: In the process for the production of diaryl carbonates by oxidative carbonylation of the underlying aromatic hydroxy compounds in the presence of a catalyst containing a platinum group metal, a co-catalyst, a quaternary salt and a base, the catalyst is used as a supported catalyst in a stationary arrangement or in the fluid phase and the reaction is performed in the condensed phase. The co-catalyst is preferably also attached to the support.

Abstract: Aromatic amines are produced by hydrogenation of the associated aromatic nitro compounds in the gas phase over fixed catalysts. The catalysts contain active hydrogenation metals on supports. The reaction is conducted at a pressure of 2-50 bar and at a temperature in the range 250.degree.-500.degree. C. under adiabatic conditions. A circulating gas is passed over the catalyst, which circulating gas contains 3-150 moles of hydrogen, 2-100 moles of the amino groups to be formed per mole of nitro groups, and 2 to 6 moles of water per amino group equivalent. The amine and water formed, as well as a purification stream, are separated from the circulating gas. Thereafter the circulating gas is enriched with volatilised aromatic nitro compound and fresh hydrogen and recycled.

Abstract: The invention relates to a process for the synthesis of bis-(4-hydroxyphenyl)-alkanes on ion-exchange resins or mixtures of ion-exchange resins which are modified with alkyl-SH groups, wherein the monophenols and carbonyl compounds to be used have first been purified to remove substances which can transfer alkyl groups.

Abstract: A description is given of the preparation of hydroxybiphenyl by dehydrogenation of completely or partially hydrogenated precursors using a supported Rh catalyst which additionally contains chromium, manganese and alkali metal and can contain a sulphur compound. The Rh catalyst which can be used according to the invention is prepared from halide-free starting materials. The Rh catalyst is distinguished by a low dependence of the initial selectivity, with the selectivity in the run-in state and the running-in time on the conditions of the reductive pretreatment and requires only short running-in times to reach the optimum state.

Abstract: The invention relates to a process for the preparation of benzyl alcohol by hydrolysis of benzyl chloride with water at elevated temperatures, which avoids any wastewater pollution.

Abstract: The invention relates to a process for preparing a diaryl carbonate by oxidative carbonylation of the basic aromatic hydroxy compound, in which the aromatic hydroxy compound is the one which is eliminated during melt polycondensation of this diaryl carbonate with a bisphenol. Accordingly the invention also relates to the preparation of polycarbonates by melt polycondensation of diaryl carbonates with bisphenols in which the aromatic hydroxy compounds which is eliminated is used again to prepare the diaryl carbonate. In the event that the aromatic hydroxy compound eliminated is also the basic unit in the bisphenol used, proportions of it may be used to prepare both the diaryl carbonate and the bisphenol.

Abstract: The present invention relates to a distillation process for the purification of carbonic acid diaryl esters.

Abstract: A novel process for the preparation of benzyl alcohol by the hydrolysis of benzyl chloride, which operates with from 10 to 70 times the molar quantity of water at temperatures of from 80.degree. to 180.degree. C. and stops the reaction before complete conversion is reached, avoids both the addition of bases and water-soluble organic solvents and also the formation of sodium chloride.

Abstract: Phenols monomethylated or dimethylated in the ortho or para position to the OH group and having the formula ##STR1## can be prepared by reaction of tert-alkyl-substituted phenols of the formula ##STR2## in which at least one free ortho or para position to the OH group is present, in three reaction steps a), b) and c). In a), (II) is reacted with formaldehyde or its polymers and a carboxylic acid of the formulaR.sup.3 --COOH, (III)which gives a mixture of substituted phenols of the formulae ##STR3## In b) the mixture of (IV)/(V) is hydrogenated using catalytically activated hydrogen to give the substituted phenols of the formula ##STR4## which, if m=0, are reacted in c) in the presence of an acid cleavage catalyst with elimination of tert-alkenes to give the methylated phenols of the formula (I).Before or during the hydrogenation, the phenols of the formulae (IV) and (V) can be reacted with the aid of an alcohol of the formulaR.sup.

Abstract: For the continuous preparation of 6-oxo-(6H)-dibenz-?c,e!?1,2!-oxaphosphorins (ODOPs), 6-chloro-(6H)-dibenz-?c,e!?1,2!-oxaphosphorins (CDOPs) are continuously reacted with at least the stochiometrically required amount of water at elevated temperature in a reaction section having little backmixing.

Abstract: Diaryl carbonate and an aromatic hydroxy compound are simultaneously separated from a crude reaction mixture for producing diaryl carbonates by oxidative carbonylation of the aromatic hydroxy compound and containing the diaryl carbonate and excess hydroxy compound together with the catalyst system, consisting of a noble-metal catalyst, co-catalyst, quaternary salt and a base. The crude reaction mixture is mixed with a covalent aprotic extraction agent, a phase separation is carried out into a donor phase containing the catalyst system and a recipient phase containing the diaryl carbonate and the hydroxy compound in concentrated form, and the diaryl carbonate and the hydroxy compound are isolated from the recipient phase.

Abstract: The present invention relates to a process for the continuous production of diaryl carbonates by reaction of aromatic hydroxy compounds with phosgene in the presence of heterogeneous catalysts.