Abstract: Substituted cyclohexanones of the formula ##STR1## where R.sup.1 to R.sup.5 are as defined in the description, can be obtained by catalytic hydrogenation of phenols of the formula ##STR2## where R.sup.1 to R.sup.5 are as defined in the description.The reaction is carried out at from 20.degree. to 250.degree. C., from 1 to 200 bar and in an ether as solvent. If desired, an alkaline alkali metal, alkaline earth metal or ammonium compound is used as additive.

Abstract: Alkyl carbazates of the formula R.sup.1 --O--CO--NH--NH.sub.2 (I) are prepared in an advantageous manner by reacting an alkyl carbazate of the formula R.sup.2 --O--CO--NH--NH.sub.2 (II) with alcohols of the formula R.sup.1 --OH (III) in the presence of a catalyst, where the symbols used in the formulae are as defined in the description.

Abstract: It has been found that cyclopentene and hydrogen bromide can be continuously reacted in a simple manner to give cyclopentyl bromide in good yields and good selectivities if the reaction is carried out in the presence of a heterogeneous catalyst. The reaction can be carried out continuously and unreacted cyclopentene and possibly other constituents can be recirculated to the reaction.

Abstract: Substituted 1,2,3,4-tetrahydrocarbazoles of the formula ##STR1## having the meaning for R.sup.1 to R.sup.8 indicated in the description, can be prepared by catalytically hydrogenating a substituted phenol of the formula ##STR2## reacting the hydrogenation solution with a phenylhydrazine of the formula ##STR3## to give the hydrazone and cyclizing the hydrazone under acidic conditions.

Abstract: C.sub.1 -C.sub.4 -Alkyl nitrites can be prepared by reaction of C.sub.1 -C.sub.4 -alkanols with nitrogen oxides with the participation of oxygen in a reactor designed as a scrubber column, nitrogen oxides having a proportion of more than 50% of NO of the total amount of gram atoms of N of the nitrogen oxides, oxygen and optionally inert gas being fed into the lower part of the reactor. 5 to 60% of the total amount of C.sub.1 -C.sub.4 -alkanol used is likewise fed into the lower part of the reactor in vaporous or atomized form, while the remaining C.sub.1 -C.sub.4 -alkanol is delivered to the column head.

Abstract: Substituted chloroaromatics are obtained in a simple manner in virtually isomer-free form when substituted phenols of the formula (II) ##STR1## where R.sup.1 to R.sup.5 are each, independently of one another, hydrogen, C.sub.1 -C.sub.10 -alkyl, unsubstituted or substituted C.sub.6 -C.sub.10 -aryl or halogen, with at least one of these radicals being different from hydrogen,are reacted with dichlorotriphenylphosphorus.

Abstract: Alkyl nitrite-containing exhaust gases are purified in continuous form by treating them with equimolar to excess amidosulphuric acid in the form of an aqueous solution in the manner of a counter-current scrubbing at a temperature of 0.degree.-100.degree. C.

Abstract: The reaction of nitrogen dioxide with hydrogen chloride to give nitrosyl chloride and nitric acid can be advantageously carried out in cocurrent in a reactor in such a way that the reactants are introduced at the bottom and the nitrosyl chloride is taken off at the top and the nitric acid is taken off at the bottom of the reactor.

Abstract: p-Amino-phenols are advantageously prepared by catalytic hydrogenation of the aromatic nitro compounds on which they are based in a reaction medium of aqueous sulphuric acid in the sense of a Bamberger rearrangement at elevated temperature by a procedure in which the reaction medium additionally contains a water-miscible organic solvent.

Abstract: Dimethyl carbonate (DMC) is prepared by continuous gas reaction of carbon monoxide and methyl nitrite a heterogeneous catalyst comprising a platinum at 50.degree. to 170.degree. C. under 1 to 5 bar.

Abstract: Dimethyl carbonate is obtained with a high selectivity and great constancy over time by reacting carbon monoxide with methyl nitrite in a continuous gas phase reaction in the presence of a heterogeneous catalyst prepared by the application to a suitable support of one or more palladium compounds of the formula[Pd(N(R.sup.1, R.sup.2, R.sup.3)).sub.n ]X.sup.1.sub.2 (I) ,wherein R.sup.1, R.sup.2, R.sup.3, X.sup.1 and n are as defined in the disclosure, optionally in combination with one or more promoters from the group consisting of the elements Fe, Co, Ni, V, Nb, Mo, Ta, Ti, Cu and Cr, the rare earths and/or compounds thereof, and/or with one or more promoters from the group consisting of alkali metal and alkaline earth metal halides.

Abstract: Heterosubstituted acetals of the formula ##STR1## can be obtained by reacting vinyl compounds of the formulaCH.sub.2 .dbd.CH-A.sup.1 (II)with alkyl nitrites of the formulaR.sup.1 --ONO (III.)The reaction is performed in the presence of palladium in metallic or bonded form and in alcohols or ethers as reaction medium at from 0.degree. to 120.degree. C.

Abstract: Dialkyl carbonates can be prepared by reacting carbon monoxide with alkyl nitrites in a continuous gas phase reaction in the presence of a heterogeneous platinum metal catalyst, the activity of this catalyst being maintained by the addition of small amounts of halogen. The dialkyl carbonates are thus formed with almost quantitative selectivity and no deactivation of the catalyst occurs.

Abstract: Methanol can be substantially removed from dimethyl carbonate (DMC)/methanol mixtures by absorption on ion exchange resins. The enriched DMC is obtained as filtrate. The absorption is carried out at from -50.degree. C. to +100.degree. C. and 0.1-10 bar.

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: Dialkyl carbonates can be prepared by reaction of carbon monoxide with alkyl nitrites in a continuous gas-phase reaction using a platinum metal catalyst on a metal phosphate support and adding hydrogen halide stepwise or continuously during the course of the reaction in almost quantitative selectivity; the corresponding dialkyl oxalates are formed in such small amounts that in most cases they cannot be detected.

Abstract: C.sub.1 -C.sub.6 -Alkyl nitrites can be prepared by reacting nitrogen dioxide with C.sub.1 -C.sub.6 -alcohols, by, in a counterflow-operated column, feeding the alcohol or an alcohol/water mixture into the upper part of the column and the nitrogen dioxide or a nitrogen dioxide/inert gas mixture into the lower part of the column. The resulting alkyl nitrite is removed from the column as the top product and the co-formed nitric acid is removed from the column as the bottom product.

Abstract: Dialkyl carbonates can be prepared by the reaction of carbon monoxide with alkyl nitrites in a continuous gas phase reaction, using a platinum group metal catalyst on an alumosilicate zeolite having acidic centers, preferably in the H.sup.+ form, as a support, which catalyst may optionally comprise additional material of a compound of antimony, bismuth, aluminum, copper, vanadium, niobium, tantalum, tin, iron, cobalt, nickel or a mixture of a plurality of these, and hydrogen halide being added in the course of the reaction intermittently or continuously. In this reaction, the dialkyl carbonates are formed with almost quantitative selectivity; the corresponding dialkyl oxalates cannot be detected in most cases.

Abstract: Dialkyl carbonates can be prepared by the reaction of carbon monoxide with alkyl nitrites in a continuous gas phase reaction, using a platinum metal catalyst on an amorphous alumosilicate having a content of 30-80 atom% Al, based on the sum of Al and Si, as a support, which catalyst may optionally comprise additional material of a compound of antimony, bismuth, aluminium, copper, vanadium, niobium, tantalum, tin, iron, cobalt, nickel or a mixture of a plurality of these, and hydrogen halide being added in the course of the reaction intermittently or continuously. In this reaction, the dialkyl carbonates are formed with almost quantitative selectivity; the corresponding dialkyl oxalates cannot be detected in most cases.

Abstract: Aromatic amines which are substituted by C.sub.1 -C.sub.4 -alkoxy in the p-position are prepared by catalytic hydrogenation of the underlying aromatic nitro compounds in a reaction medium comprising sulphuric acid and a C.sub.1 -C.sub.4 -alcohol by a Bamberger type rearrangement at elevated temperature, advantageously by carrying out the catalytic hydrogenation under elevated pressure.