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: Diphenylamine can be dehydrocyclized on noble metal catalysts in the liquid phase at temperatures of 200.degree. to 340.degree. C. The reaction proceeds with a surprisingly high selectivity.

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: Novel ruthenium catalysts additionally contain carbonates, hydroxides and/or hydrated oxides of cerium and manganese or of manganese and/or dehydration products thereof. They can optionally be present on a support material and can be prepared by converting soluble compounds of ruthenium, cerium and manganese by treatment with alkaline compounds into insoluble compounds and optionally further treating these. Such catalysts are particularly suitable for the preparation of cycloaliphatic polyamines by hydrogenation of corresponding aromatic amines.

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: Succinic anhydride (SA) can be prepared by catalytic hydrogenation of maleic anhydride (MA) with hydrogen in the liquid phase, by reacting a starting material composed of from 5 to 100% by weight of MA and from 95 to 0% by weight of SA, based on the total weight of MA and SA, at from 120.degree. to 150.degree. C. and a H.sub.2 pressure of from 10 to 150 bar over a Raney skeleton catalyst or a platinum group metal catalyst.

Abstract: New hydrated niobium oxide and hydrated tantalum oxide catalysts containing pores having diameters in the range from 0.4 to 10,000 nm are characterized in that the volume of the pores of the catalyst having a diameter of from 100 to 1000 nm is at least 30% of the total pore volume of the catalyst. The catalysts can be prepared by mixing hydrated niobium oxide or hydrated tantalum oxide with an inert solid and converting this mixture into a solid pellet form, with the pressure in the apparatus for preparing catalysts in pellet form being set in such a way that the volume of the pores of the catalyst having a diameter of from 100 to 1000 nm is at least 30% of the total pore volume of the catalyst. Such catalysts are particularly suitable for preparing N-alkylanilines from anilines and alkanols.

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: 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: Chlorine-substituted aromatic amines are prepared by the hydrogenation of chlorine-substituted aromatic nitro compounds in the presence of a catalyst containing platinum and nickel and/or cobalt on an activated charcoal support, the platinum having been simultaneously deposited and reduced on the activated charcoal support in the preparation of the catalyst. Such catalysts are furthermore prepared, as are catalysts containing noble metals on an activated charcoal support, it also being possible for the latter to be used for the reduction of nitronaphthalenes or nitrotoluenes.

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.

Abstract: A carbon- and nitrogen-based catalyst consisting essentially of active carbon or active coke and comprising at least 90% by weight of graphite structures containing at least 10% of pores larger than 100 nm in diameter and having incorporated therein an isocyanate which forms C-N-ring structures, the percentage graphite content being at least 90% by weight. The catalayst is especially effective in the low temperature reduction of nitrogen oxides in waste gases.

Abstract: The invention relates to mixtures of polyarylene sulfides (PAS), preferably polyphenylene sulfide (PPS), and pyrenes. The mixtures show reduced radical formation under highly accelerated weathering conditions (UV irradiation).

Abstract: A process for the absorption of chlorine from a chlorine-containing gas, comprising contacting the chlorine-containing gas with an aqueous solution containing about 1 to 400 g/l of iron(II) chloride and at least one of copper (I) and copper(II) ions, the chlorine being adsorbed with conversion of the iron(II) chloride into iron(III) chloride, thereafter electrolyzing the iron(III) chloride to form chlorine and iron(II) chloride and recycling the iron(II) chloride for the absorption of additional chlorine. Advantageously the chlorine-containing gas has a chlorine content of from about 10 to 20% by volume, the iron(II) chloride solution contains about 0.1 to 10 g/l of at least one of CuCl.sub.2 and CuCl, and the contact of the chlorine-containing gas with the iron(II) chloride soluton is carried out at a temperature of from about 40.degree. to 50.degree. C and under a pressure of the order of about 1 bar.

Abstract: In the electrolysis of an alkaline earth metal-containing alkali metal brine wherein the alkaline earth metals contained in the brine are removed, the brine is subjected to electrolysis, and the residual brine is concentrated and recycled for further electrolysis along with make-up fresh brine, the improvement which comprises contacting the alkaline earth metal-containing brine with a weakly acidic cation exchanger in the Na+ form, the exchanger comprising units of at least one of acrylic acid and methacrylic acid, whereby the alkaline earth metals are adsorbed on the cation exchanger, and periodically regenerating the cation exchanger. The cation exchanger is regenerated by contact with a hydrochloric acid solution of about 5 to 10% concentration, the regenerating solution effluent from the column being combined with the redissoluted sodium sulphate which is precipitated during concentration of the cell liquor thereby to precipitate any sulphate contained in the brine as the alkaline earth metal sulphate.

Abstract: A process for the remote transmission and indication of measured values of a plurality of electrolysis cells, comprising sequentially interrogating the measured values in the electrolysis cells by means of an electronic pulse counter and an electronic check-point reversing switch connected to the pulse counter, transmitting the measured values in the form of an analogue signal to a separate monitoring facility common to said cells, and controlling the electronic pulse counter at the electrolysis cell from the monitoring facility by switching pulses or a pulse series, a maximum of four signal wires being provided between each electrolysis cell and the monitoring facility irrespective of the number and type of check points.

Abstract: Brine is purified prior to electrolysis by dividing it into two streams, removing sulfate from one of the streams by precipitation with calcium chloride to form calcium sulfate, removing the precipitate and re-combining the streams. Alkali hydroxide plus sodium carbonate are added to the re-combined streams to precipitate calcium carbonate which is removed. Any magnesium comes down as the hydroxide. The brine is then pure enough for electrolysis The calcium sulfate first precipitate is reacted with sodium hydroxide and carbon dioxide to form calcium carbonate which is then reacted with hydrochloric acid to form calcium chloride which is recycled to the process for precipitating calcium sulfate.