Abstract: Process for preparing chlorine by oxidation of hydrogen chloride by means of oxygen in the presence of a particulate catalyst in a fluidized-bed reactor, where the heat of reaction of the exothermic oxidation of hydrogen chloride is removed by means of water which circulates in the tubes of a shell-and-tube heat exchanger, where (i) the fluidized-bed reactor is heated up to an operating temperature in the range from 350 to 420° C. in a heating-up phase and (ii) hydrogen chloride is reacted with oxygen in an operating phase at the operating temperature, wherein (i-1) the fluidized-bed reactor is heated up to a temperature below the operating temperature in a first heating-up phase and (i-2) hydrogen chloride and oxygen are fed into the fluidized-bed reactor and reacted in a second heating-up phase in which the fluidized-bed reactor is heated up to the operating temperature by the heat of reaction of the exothermic oxidation of hydrogen chloride.

Abstract: The invention relates to a process for regenerating a hydrogen chloride oxidation catalyst comprising ruthenium oxide on a support material, which comprises the steps a) reduction of the catalyst in a gas stream comprising hydrogen chloride and optionally an inert gas at a temperature of from 100 to 800° C., b) recalcination of the catalyst in an oxygen-comprising gas stream at a temperature of from 150 to 800° C.

Abstract: The invention relates to a process for the catalytic oxidation of hydrogen chloride by means of oxygen to form chlorine in a fluidized-bed process in the presence of a catalyst comprising ruthenium on a particulate support composed of alpha-aluminum oxide having an average particle size of from 10 to 200 ?m, wherein the catalyst support has a low surface roughness and can be obtained from a used catalyst which has been used in a fluidized-bed process for at least 500 hours of operation.

Abstract: Catalyst comprising ruthenium on a support for the catalytic oxidation of hydrogen chloride by means of oxygen to form chlorine, wherein the catalyst comprises from 0.01 to 10% by weight of silver and/or calcium as dopant. The support preferably consists essentially of alpha-aluminum oxide. The catalyst preferably comprises a) from 0.1 to 10% by weight of ruthenium, b) from 0.01 to 5% by weight of silver and/or from 0.01 to 5% by weight of calcium, c) from 0 to 5% by weight of one or more alkaline earth metals, d) from 0 to 5% by weight of one or more alkali metals, e) from 0 to 5% by weight of one or more rare earth metals, f) from 0 to 5% by weight of one or more further metals selected from the group consisting of nickel, palladium, platinum, iridium and rhenium, in each case based on the total weight of the catalyst.

Abstract: This invention relates to a process for working up residues from production of isocyanates. This process involves hydrolyzing residues from production of at least one isocyanate with water to form a hydrolysis product, and processing the hydrolysis product within an extruder or a kneader having a heat transfer surface, to form a mixed product containing at least one amine and water. The amine and the water are separated from the mixed product to form an amine/water mixture, which is then separated to obtain the water and the amine. The process may also involve separating all or part of the water from the hydrolysis, or separating part of the amine from the hydrolysis, prior to the processing of the hydrolysis product.

Abstract: The invention relates to a process for recovering ruthenium from a used ruthenium-comprising catalyst which comprises ruthenium as ruthenium oxide on a support material which is not readily soluble in mineral acid, which comprises the steps: a) the ruthenium oxide-comprising catalyst is reduced in a gas stream comprising hydrogen chloride and, if appropriate, an inert gas at a temperature of from 300 to 500° C.; b) the reduced catalyst from step a) comprising metallic ruthenium on the sparingly soluble support material is treated with hydrochloric acid in the presence of an oxygen-comprising gas, with the metallic ruthenium present on the support being dissolved as ruthenium(III) chloride and obtained as an aqueous ruthenium(III) chloride solution; c) if appropriate, the ruthenium(III) chloride solution from step b) is worked up further.

Abstract: A process for preparing chlorine by gas-phase oxidation of hydrogen chloride over a heterogeneous, particulate catalyst in a fluidized-bed reactor to give a product gas mixture which is freed of entrained catalyst particles in cyclones (1) which are arranged in the upper region of the fluidized-bed reactor, which comprises a cylindrical upper part (2) which has a tangential or spiral-shaped inlet (3) for the product gas mixture and tapers at its lower end via a conical section (4) into a cyclone downcomer tube (5) and also a central downward-extending tube (6) in the upper region of the cyclone (1) for discharging the product gas mixture which has been freed of entrained catalyst particles, wherein from one to seven cascades of in each case from two to five cyclones (1) connected in series are used, with the cyclones (1) of each cascade, with the exception of the first cyclone (1) through which flow occurs in each case, which is designed so that about 90 to 99% by weight of the entrained catalyst particles ar

Abstract: An oxidation process employing a mechanically stable catalyst of an active metal or combination of active metals supported on aluminum oxide, which is predominantly alpha-aluminum oxide, is provided. The active metal or metals is optionally one or a mixture of ruthenium, copper, gold, an alkaline earth metal, an alkali metal, palladium, platinum, osmium, iridium, silver, and rhenium. The process is applicable to the oxidation of hydrogen chloride to chlorine in a Deacon process.

Abstract: Process for preparing chlorine by oxidation of hydrogen chloride by means of oxygen in the presence of a particulate catalyst in a fluidized-bed reactor, where the heat of reaction of the exothermic oxidation of hydrogen chloride is removed by means of water which circulates in the tubes of a shell-and-tube heat exchanger, where (i) the fluidized-bed reactor is heated up to an operating temperature in the range from 350 to 420° C. in a heating-up phase and (ii) hydrogen chloride is reacted with oxygen in an operating phase at the operating temperature, wherein (i-1) the fluidized-bed reactor is heated up to a temperature below the operating temperature in a first heating-up phase and (i-2) hydrogen chloride and oxygen are fed into the fluidized-bed reactor and reacted in a second heating-up phase in which the fluidized-bed reactor is heated up to the operating temperature by the heat of reaction of the exothermic oxidation of hydrogen chloride.

Abstract: The invention relates to a process for the catalytic oxidation of hydrogen chloride by means of oxygen to form chlorine in a fluidized-bed process in the presence of a catalyst comprising ruthenium on a particulate support composed of alpha-aluminum oxide having an average particle size of from 10 to 200 ?m, wherein the catalyst support has a low surface roughness and can be obtained from a used catalyst which has been used in a fluidized-bed process for at least 500 hours of operation.

Abstract: Catalyst comprising ruthenium on a support for the catalytic oxidation of hydrogen chloride by means of oxygen to form chlorine, wherein the catalyst comprises from 0.01 to 10% by weight of silver and/or calcium as dopant. The support preferably consists essentially of alpha-aluminum oxide. The catalyst preferably comprises a) from 0.1 to 10% by weight of ruthenium, b) from 0.01 to 5% by weight of silver and/or from 0.01 to 5% by weight of calcium, c) from 0 to 5% by weight of one or more alkaline earth metals, d) from 0 to 5% by weight of one or more alkali metals, e) from 0 to 5% by weight of one or more rare earth metals, f) from 0 to 5% by weight of one or more further metals selected from the group consisting of nickel, palladium, platinum, iridium and rhenium, in each case based on the total weight of the catalyst.

Abstract: A catalytic process for preparing chlorine from hydrogen chloride, which includes recycle of process streams with reduced accumulation of inert gases in the system is provided. The process includes a step wherein a compressed liquid stream comprising chlorine, carbon dioxide and oxygen is recycled into a column countercurrent to the ascending gas phase and feeding part of the chlorine-rich liquid phase leaving the bottom of the column back into the top of the column. Carbon dioxide present in the ascending gas stream is dissolved out of the gas stream and can later be separated from chlorine without problems by distillation.

Abstract: A process for preparing chlorine by oxidation of hydrogen chloride in the presence of a heterogeneous particulate catalyst by the Deacon process in a fluidized-bed reactor (1), in which the heat of reaction is removed by evaporative cooling by means of water which circulates in the tubes (2) of a shell-and-tube heat exchanger, with the water being fed from a steam drum (4) via a feed line (5) to the tubes (2) of the shell-and-tube heat exchanger at one end of these, being heated in the tubes (2) by uptake of the heat of reaction and partly vaporizing to give a water/steam mixture which at the other end of the tubes (2) of the shell-and-tube heat exchanger is recirculated via a return line (6) to the steam drum (4), wherein the maximum pressure for which the fluidized-bed reactor (1) has to be designed to allow for the event of rupture of a tube (2) of the shell-and-tube heat exchanger is minimized by a valve (7) which in the event of a pressure increase as a result of rupture of a tube (2) closes the feed lin

Abstract: The invention relates to a process for recovering ruthenium from a used ruthenium-comprising catalyst which comprises ruthenium as ruthenium oxide on a support material which is not readily soluble in mineral acid, which comprises the steps: a) the ruthenium oxide-comprising catalyst is reduced in a gas stream comprising hydrogen chloride and, if appropriate, an inert gas at a temperature of from 300 to 500° C.; b) the reduced catalyst from step a) comprising metallic ruthenium on the sparingly soluble support material is treated with hydrochloric acid in the presence of an oxygen-comprising gas, with the metallic ruthenium present on the support being dissolved as ruthenium(III) chloride and obtained as an aqueous ruthenium(III) chloride solution; c) if appropriate, the ruthenium(III) chloride solution from step b) is worked up further.

Abstract: The invention relates to a process for regenerating a hydrogen chloride oxidation catalyst comprising ruthenium oxide on a support material, which comprises the steps a) reduction of the catalyst in a gas stream comprising hydrogen chloride and optionally an inert gas at a temperature of from 100 to 800° C., b) recalcination of the catalyst in an oxygen-comprising gas stream at a temperature of from 150 to 800° C.

Abstract: Catalyst for gas-phase reactions which has a high mechanical stability and comprises one or more active metals on a support comprising aluminum oxide as support material, wherein the aluminum oxide component of the support consists essentially of alpha-aluminum oxide. Particularly preferred catalysts according to the invention comprise a) from 0.001 to 10% by weight of ruthenium, copper and/or gold, b) from 0 to 5% by weight of one or more alkaline earth metals, c) from 0 to 5% by weight of one or more alkali metals, d) from 0 to 10% by weight of one or more rare earth metals, e) from 0 to 10% by weight of one or more further metals selected from the group consisting of palladium, platinum, iridium and rhenium, in each case based on the total weight of the catalyst, on the alpha-Al2O3 support. The catalysts are preferably used in the oxidation of hydrogen chloride (Deacon reaction).

Abstract: The invention relates to a method of operating a liquid ring compressor having an impeller installed eccentrically in a compressor body, with gas being supplied to the liquid ring compressor on a suction side and gas being discharged from the liquid ring compressor on a pressure side. A liquid ring is generated in the liquid ring compressor on the inside of the compressor body by rotation of the impeller. Chambers are formed between blades of the impeller and the liquid ring and gas is drawn into these. The gas is compressed in the chambers which become smaller from the suction side to the pressure side as a result of the rotation of the eccentrically mounted impeller. The compressed gas is ejected on the pressure side. An ionic liquid is used as service liquid for generation of the liquid ring.

Abstract: A catalyst for gas-phase reactions which has high mechanical stability and comprises one or more active metals on a support comprising aluminum oxide as support material, wherein the aluminum oxide in the support consists essentially of alpha-aluminum oxide. Ruthenium, copper and/or gold are preferred as active metal. Particularly preferred catalysts according to invention comprise a) from 0.001 to 10% by weight of ruthenium, copper and/or gold, b) from 0 to 5% by weight of one or more alkaline earth metals, c) from 0 to 5% by weight of one or more alkali metals, d) from 0 to 10% by weight of one or more rare earth metals, e) from 0 to 10% by weight of one or more further metals selected from the group consisting of palladium, platinum, osmium, iridium, silver and rhenium, in each case based on the total weight of the catalyst, on the support comprising alpha-Al2O3. The catalysts are preferably used in the oxidation of hydrogen chloride (Deacon reaction).

Abstract: The invention relates to a process for preparing polyisocyanates by reacting primary amines with phosgene in the presence of a solvent, wherein ionic liquids are used as solvents.

Abstract: The invention relates to a process for the work-up of residues from the production of isocyanates, which comprises the steps: a) hydrolysis of the residues by means of water, b) introduction of the reaction product from step a) into a mixer having a heat transfer surface, c) separation of amine and water from the output from step b), d) separation of water and amine.