Abstract: Process for preparing organic isocyanates, which comprises the steps (a) making available a first partial amount of chlorine, with the chlorine of this first partial amount having a content of free and bound bromine and iodine of <400 ppm; (b) making available a second partial amount of chlorine; (c) reacting the first and second partial amounts of chlorine with carbon monoxide to form phosgene; (d) reacting the phosgene from step (c) with one or more primary amines to form the corresponding isocyanates and hydrogen chloride; (e) separating off and, if necessary, purifying the isocyanates formed in step (d); (f) separating off and, if necessary, purifying the hydrogen chloride formed in step (d); (g) catalytically oxidizing at least part of the hydrogen chloride separated off in step (e) by means of oxygen to form chlorine; (h) separating off the chlorine formed in step (g) and using at least a partial amount of the chlorine which has been separated off as second partial amount of chlorine in step (b).

Abstract: A process for regenerating a dehydrogenation catalyst comprises the steps (a)-(f): (a) flushing with inert gas at a pressure of from 0.5 to 2.0 bar and a gas hourly velocity of from 1000 to 50 000 h?1; (b) passing an oxygen-containing gas mixture comprising an inert gas through the catalyst at a pressure of from 2 to 20 bar and a gas hourly velocity of from 1000 to 50 000 h?1 for from 0.25 to 24 hours while increasing the oxygen concentration stepwise or continuously from an initial value of from 0.01 to 1% by volume of O2 to a final value of from 10 to 25% by volume of O2; (c) optionally passing an oxygen-containing gas mixture comprising an inert gas through the catalyst at a pressure of from 0.5 to 20 bar and a gas hourly velocity of from 10 to 500 h?1 for from 0.25 to 100 h, with the oxygen concentration being from 10 to 25% by volume of O2; (d) optionally changing the pressure repeatedly, rapidly and in opposite directions by a factor of from 2 to 20 within the range from 0.

Abstract: A process for preparing alkenylaromatic compounds by reacting alkylaromatic compounds in the presence of steam and natural gas or methane over a suitable catalyst at a temperature of from 400 to 800° C. and a pressure of from 0.01 to 10 bar, wherein the molar ratio of steam to alkylaromatic compound is from 6.9:1 to 1:1 or the molar ratio of methane to alkylaromatic compound is from 0.1:1 to 8:1.

Abstract: A process for the continuous heterogeneously catalyzed partial dehydrogenation of a hydrocarbon in the gas phase and in the presence of molecular oxygen, in which part of the product gas is recirculated to the reaction zone, and a reactor for carrying out such a process.

Abstract: A process for preparing 1,2-dichloroethane which comprises (A) feeding an ethane-containing feed gas stream into a dehydrogenation zone and dehydrogenating ethane to ethane to give a product gas stream comprising ethane, ethane and secondary constituents, (B) feeding the ethan- and ethene-containing dehydrogenation product gas stream as a single stream or a plurality of substreams, optionally after having separated off secondary constituents, into one or more chlorination zones, chlorinating ethene to 1,2-dichloroethane to give one or more product gas streams comprising 1,2-dichloroethane, ethane and possibly further secondary constituents, isolating 1,2-dichloroethane and one or more ethane-containing circulating gas streams and recirculating the ethane-containing circulating gas stream or streams to the ethane dehydrogenation.

Abstract: A catalyst suitable for the gas-phase oxidation of organic compounds to ?,?-unsaturated aldehydes and/or carboxylic acids and having an active phase comprising a multimetal oxide material is prepared by a process in which a particulate catalyst precursor which contains oxides and/or compounds of the elements other than oxygen which constitute the multimetal oxide material, which compounds can be converted into oxides, is prepared and said catalyst precursor is converted by calcination into a catalytically active form, wherein a stream of the particulate catalyst precursor is passed at substantially constant speed through at least one calcination zone at constant temperature for calcination.

Abstract: A process for removing chloride from chloridic iron oxide comprises mixing said chloridic iron oxide with an acid and subsequently conducting a thermal treatment at from 50 to 1300° C.

Abstract: Catalysts for preparing carboxylic acid salts from alcohols which a) consist of copper or b) comprise from 99.9 to 10% by weight of copper and from 0.01 to 90% by weight of iron and from 0 to 50% by weight of one or more other metals, and may optionally be doped, the hydroxides being obtained by precipitation of copper salt solutions or by coprecipitation of copper and iron salt solutions optionally containing salts of other metals using a base, and being reduced by hydrogen.

Abstract: A process for preparing 1,2-dichloroethane which comprises

Abstract: The invention relates to a process for preparing 4-vinylcyclohexene, which comprises the steps

Abstract: A process for preparing at least one partial oxidation and/or ammoxidation product of a hydrocarbon by partially dehydrogenating at least one saturated hydrocarbon H under heterogeneous catalysis and using the resulting product gas mixture A, which comprises the partially dehydrogenated hydrocarbon H, as such or in modified form for heterogeneously catalyzed partial oxidation and/or ammoxidation of the partially dehydrogenated hydrocarbon present in the product gas mixture A, said process including at least one mechanical separating operation inserted between the product gas mixture A and the heterogeneously catalyzed partial oxidation and/or ammoxidation.

Abstract: C2-C30-alkanes are dehydrogenated in a process in which

Abstract: In a process for the preparation of acrolein or acrylic acid or a mixture thereof from propane, the propane is subjected, in a first reaction stage, to a partial dehydrogenation under heterogeneous catalysis to give propene, of the components contained in the product gas mixture formed in the first reaction stage other than propene and propane at least a portion of the molecular hydrogen present is then separated off from said mixture and the product gas mixture is then used for the preparation of acrolein and/or acrylic acid by gas-phase catalytic propylene oxidation, molecular nitrogen being present for diluting the reaction gas mixture during the propylene oxidation.

Abstract: A process for preparing chlorine by gas-phase oxidation of hydrogen chloride by means of a gas stream comprising molecular oxygen in the presence of a fixed-bed catalyst, which is carried out in a reactor (1) having a bundle of parallel catalyst tubes (2) which are aligned in the longitudinal direction of the reactor and are fixed at their ends into tube plates (3), with a cap (4) at each end of the reactor (1) and with one or more annular deflection plates (6) which are arranged perpendicular to the longitudinal direction of the reactor in the intermediate space (5) between the catalyst tubes (2) and leave circular passages (8) free in the middle of the reactor and one or more disk-shaped deflection plates (7) which leave annular passages (9) free at the edge of the reactor, with an alternating arrangement of annular deflection plates (6) and disk-shaped deflection plates (7) with the catalyst tubes (2) being charged with the fixed-bed catalyst, the hydrogen chloride and the gas stream comprising molecular o

Abstract: A process for preparing chlorine by gas-phase oxidation of hydrogen chloride by means of a gas stream comprising molecular oxygen in the presence of a fixed-bed catalyst, which is carried out in a reactor (1) having a bundle of parallel catalyst tubes (2) which are aligned in the longitudinal direction of the reactor and are fixed at their ends into tube plates (3), with a cap (4) at each end of the reactor (1) and with one or more deflection plates (6) which are arranged perpendicular to the longitudinal direction of the reactor in the intermediate space (5) between the catalyst tubes (2) and leave passages (7) located alternately on opposite sides of the reactor free next to the interior wall of the reactor (1), with the catalyst tubes (2) being charged with the fixed-bed catalyst, the hydrogen chloride and the gas stream comprising molecular oxygen being passed from one end of the reactor via a cap (4) through the catalyst tubes (2) and the gaseous reaction mixture being taken off from the opposite end of

Abstract: Iron oxides are upgraded by calcining at from 700 to 1200° C.

Abstract: Particle fiber agglomerates comprise fibers having the structure of individual fibers, fiber bundles, fiber tufts or mixtures thereof with firmly adhering particles.

Abstract: A copper-containing catalyst of the composition of N2O contains a compound of the formula MxAl2O4, where M is Cu or a mixture of Cu and Zn and/or Mg and x is from 0.8 to 1.5. The novel catalyst is used in a process for the catalytic decomposition of pure N2O or N2O contained in gas mixtures, at elevated temperatures.

Abstract: Process for preparing chlorine by catalytic gas-phase oxidation of hydrogen chloride over a fixed catalyst bed, which comprises the steps:

Abstract: A catalyst suitable for the gas-phase oxidation of organic compounds to &agr;,&bgr;-unsaturated aldehydes and/or carboxylic acids and having an active phase comprising a multimetal oxide material is prepared by a process in which a particulate catalyst precursor which contains oxides and/or compounds of the elements other than oxygen which constitute the multimetal oxide material, which compounds can be converted into oxides, is prepared and said catalyst precursor is converted by calcination into a catalytically active form, wherein a stream of the particulate catalyst precursor is passed at substantially constant speed through at least one calcination zone at constant temperature for calcination.