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: 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: Hydroxymethylcyclopropane is prepared from alkyl cyclopropanecarboxylates by reduction with hydrogen in a process in which use is made of a reduced pelletized catalyst which is obtainable by pressing a mixture of pulverulent copper, zinc and aluminum oxides and subsequent reduction. This process has the advantage that it uses a low-toxicity catalyst which has a long operating life and is particularly suitable for a continuous process and requires relatively low reaction temperatures.

Abstract: Hydroxymethyl-cyclopropane (cyclopropyl-methanol) can be obtained in a manner which is both economical and environment-friendly by catalytic hydrogenation of cyclopropanecarboxylic acid alkyl esters under increased pressure at elevated temperature if a chromium-free zinc oxide catalyst is employed as the catalyst.

Abstract: Aromatic amines are produced by catalytic hydrogenation of nitroaromatic compounds in the gas phase. The catalyst includes palladium and lead on graphite or on a graphite-containing coke support. From 30 to 6000 equivalents of hydrogen for each equivalent of nitro groups are contacted with the catalyst during this process.

Abstract: A method for preparing a chloroethylglucopyranose which comprisesa) reacting glucose with from 2 to 10 times the molar amount of chloroethanol at from 100.degree. to 130.degree. C. in the absence of a catalyst, optionally removing water,b) further reacting the product of step (a) at 60.degree. to 90.degree. C. in the presence of an acidic catalyst for from 10 to 600 minutes andc) Separating therefrom the chloroethylglucopyranose.

Abstract: Isocyanates or isocyanate mixtures which contain no appreciable amounts of color causing materials are produced by phosgenating the amine corresponding to the desired isocyanate and treating the isocyanate-containing phosgenation mixture with hydrogen in the presence of a supported catalyst. The supported catalyst is in a form such that its shortest dimension is from about 0.3 to about 3.0 mm. This catalyst has a BET surface of from about 0.5 to about 150 m.sup.2 /g. No alkali material can be present in the catalyst. These isocyanates are particularly useful for the production of light-colored foams.

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: Dialkyl carbonates can be prepared by reacting carbon monoxide with alkyl nitrites in a continuous gas phase reaction in the presence of a catalyst using a fixed bed reactor with a short catalyst bed in the direction of flow. The dialkyl carbonates are formed with almost quantitative selectivity; thermal decomposition of the alkyl nitrite, with the resulting formation of decomposition products, is not observed.

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: 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.

Abstract: 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.

Abstract: Azomethines can be prepared by the condensation of cycloalkanones and anilines in the presence of acid homogeneous catalysts while the water of reaction is removed azeotropically, the condensation being carried out in a continuous reaction in a column-like reactor to which a temperature profile is applied, the starting materials being fed in in the low-temperature region, and, of the reaction products, the water of reaction to be removed azeotropically being discharged also in the low-temperature region and the azomethine produced being discharged in the high-temperature region.

Abstract: Azomethines can be prepared by the condensation of cycloalkanones and anilines in the presence of acid heterogeneous catalysts, with azeotropic removal of the water of reaction, the condensation being carried out in a continuous reaction in a column-like reactor having an applied temperature profile, and the starting materials being fed in the low-temperature zone and, of the reaction products, the water of reaction to be removed as an azeotrope also being removed in the low-temperature zone and the azomethine formed being removed in the high-temperature zone.

Abstract: The invention relates to a process for the preparation of p-substituted o-benzylphenols by reaction of p-substituted phenols with optionally substituted benzyl halides, benzyl esters, benzyl alcohols or benzyl ethers in the presence of an acid catalyst at elevated temperature in a distillation column.

Abstract: Dialkyl carbonates can be prepared in a continuous manner by transesterification of ethylene carbonate or propylene carbonate with alcohols in the presence of a catalyst in a column equipped with packing or baffles, by passing the reactants in countercurrent such that the ethylene carbonate or propylene carbonate are metered into the upper part of the column and the alcohol is metered into the lower part of the column and the catalyst is arranged as a fixed bed in the column or is also metered into the upper part of the column in solution or suspension, the dialkyl carbonate formed, if appropriate as a mixture with alcohol, being removed at the top of the column and the ethylene glycol or propylene glycol formed from the ethylene carbonate or propylene carbonate being removed at the foot of the column, if appropriate together with the catalyst.

Abstract: Diphenylamine, which can be substituted by lower alkyl and/or lower alkoxy, is obtained from the corresponding N-cyclohexylidene-aniline by catalytic dehydrogenation, a rhodium-containing catalyst being employed.