Abstract: A process for compressing a hydrogen-sulfide-comprising gas stream, which comprises (i) compressing the hydrogen-sulfide-comprising gas stream in a compressor, (ii) flushing the compressor with a mixture comprising dialkyl polysulfides, dialkyl disulfides and at least one amine; a process for producing sulfur compounds, selected from the group consisting of alkylmercaptans, dialkyl disulfides and alkanesulfonic acids, which comprises the conversion of hydrogen-sulfide-comprising gas streams, wherein the hydrogen-sulfide-comprising gas streams are compressed according to the process comprising steps i) and ii); and also the use of a mixture comprising dialkyl polysulfides, dialkyl disulfides and at least one amine for removing sulfur deposits which occur in the compression of hydrogen-sulfide-comprising gas streams.

Abstract: The invention relates to a reactor (1) and a process for continuously preparing H2S by converting a reactant mixture which comprises essentially gaseous sulfur and hydrogen over a catalyst, comprising a sulfur melt (9) at least in a lower subregion (8) of the reactor (1), into which gaseous hydrogen is introduced. The catalyst is arranged in at least one U-shaped tube (21) which is partly in contact with the sulfur melt (9), the at least one U-shaped tube (21) having at least one entry orifice (23) on a limb (26) above the sulfur melt (9), through which the reactant mixture can enter the U-shaped tube (21) from a reactant region (10) of the reactor (1), having a flow path within the at least one U-shaped tube, along which the reactant mixture can be converted in a reaction region comprising the catalyst (22), and having at least one exit orifice (24) in another limb (27) through which a product can exit into a product region (7).

Abstract: The invention relates to a process for preparing aromatic diisocyanates by reaction of phosgene with diamines in the gas phase, in which the reaction is carried out in a reaction zone at moderate pressures, i.e. the pressure in this reaction zone is more than 3 bar and less than 20 bar.

Abstract: The present invention describes a reactor (1) for continuously preparing hydrogen sulfide H2S from hydrogen and sulfur, comprising a distributor device (15) for distributing gaseous hydrogen in a sulfur melt (9) present at least in a lower part of the reactor. The distributor device (15) is arranged in the sulfur melt (9) and comprises a distributor plate (16) which is arranged in the reactor (1) and has an edge (17) extending downward and, if appropriate, has passage orifices (19). The hydrogen from a hydrogen bubble which forms below the distributor plate (16) is (for example through the passage orifices (19)) distributed in the sulfur melt (9) via the distributor plate (16).

Abstract: The present invention relates to a process for preparing diisocyanates from diamines and phosgene in the gas phase.

Abstract: Hydrogen sulfide H2S is prepared from a crude gas stream containing H2S and polysulfanes (H2Sx). The crude gas stream is passed at temperatures of from 114 to 165° C. through catalytically active material present in a vessel, and sulfur is collected in the bottom of the vessel and recycled to the preparation of H2S. This process may be accomplished in an apparatus including a reactor for reacting sulfur and hydrogen, a cooler for receiving and cooling an H2S-containing crude gas stream passed out of the reactor to between 114 to 165° C., a vessel coupled to the cooler, the vessel including catalytically active material and a bottom for collecting sulfur obtained from the crude gas stream, and a line which is connected to the bottom of the vessel and opens into the cooler or into the reactor, for recycling sulfur.

Abstract: The present invention describes a reactor (1) for continuously preparing hydrogen sulfide H2S from hydrogen and sulfur, comprising a distributor device (15) for distributing gaseous hydrogen in a sulfur melt (9) present at least in a lower part of the reactor. The distributor device (15) is arranged in the sulfur melt (9) and comprises a distributor plate (16) which is arranged in the reactor (1) and has an edge (17) extending downward and, if appropriate, has passage orifices (19). The hydrogen from a hydrogen bubble which forms below the distributor plate (16) is (for example through the passage orifices (19)) distributed in the sulfur melt (9) via the distributor plate (16).

Abstract: The invention relates to a process for preparing polyisocyanates by reacting organic amines with phosgene, wherein the reaction is carried out in at least three stages, with the first stage being carried out in a mixing apparatus, the second stage in at least one residence apparatus and the third stage in at least one separation apparatus and the pressure in each successive stage being lower than that in the previous stage.

Abstract: The invention relates to a process and to an apparatus for preparing hydrogen sulfide H2S by converting a reactant mixture which comprises gaseous sulfur and hydrogen over a solid catalyst. The reactant mixture is converted at a pressure of from 0.5 to 10 bar absolute, a temperature of from 300 to 450° C. and a sulfur excess in a reactor (1). The sulfur excess corresponds to a ratio of excess sulfur to H2S prepared of from 0.2 to 3 kg of sulfur per kg of H2S prepared.

Abstract: The present invention relates to a process for preparing diisocyanates from diamines and phosgene in the gas phase.

Abstract: The invention relates to a process for preparing isocyanates in the gas phase.

Abstract: The invention relates to a reactor (1) and a process for continuously preparing H2S by converting a reactant mixture which comprises essentially gaseous sulfur and hydrogen over a catalyst, comprising a sulfur melt (9) at least in a lower subregion (8) of the reactor (1), into which gaseous hydrogen is introduced. The catalyst is arranged in at least one U-shaped tube (21) which is partly in contact with the sulfur melt (9), the at least one U-shaped tube (21) having at least one entry orifice (23) on a limb (26) above the sulfur melt (9), through which the reactant mixture can enter the U-shaped tube (21) from a reactant region (10) of the reactor (1), having a flow path within the at least one U-shaped tube, along which the reactant mixture can be converted in a reaction region comprising the catalyst (22), and having at least one exit orifice (24) in another limb (27) through which a product can exit into a product region (7).

Abstract: The invention relates to a process for preparing isocyanates in the gas phase.

Abstract: The present invention relates to a process for preparing isocyanates.

Abstract: The present invention relates to a process for preparing diisocyanates from diamines and phosgene in the gas phase.

Abstract: The invention relates to a process for separating hydrogen chloride and phosgene, which comprises bringing a mixture of hydrogen chloride and phosgene into contact with an ionic liquid in which at least part of the hydrogen chloride is dissolved in a step a) and then separating off the hydrogen chloride dissolved in the ionic liquid in a step b).

Abstract: The present invention describes a reactor (1) for continuously preparing hydrogen sulfide H2S from hydrogen and sulfur, comprising a distributor device (15) for distributing gaseous hydrogen in a sulfur melt (9) present at least in a lower part of the reactor. The distributor device (15) is arranged in the sulfur melt (9) and comprises a distributor plate (16) which is arranged in the reactor (1) and has an edge (17) extending downward and, if appropriate, has passage orifices (19). The hydrogen from a hydrogen bubble which forms below the distributor plate (16) is (for example through the passage orifices (19)) distributed in the sulfur melt (9) via the distributor plate (16).

Abstract: The invention relates to a process and to an apparatus for continuously preparing hydrogen sulfide H2S, polysulfanes (H2Sx) being present in an H2S-containing crude gas stream obtained in the preparation. The crude gas stream is passed at temperatures of from 114 to 165° C. through catalytically active material (41) present in a vessel (42), and sulfur obtained here is collected in the bottom (43) of the vessel (42) and recycled to the preparation of H2S. The inventive apparatus comprises a reactor (1) for reacting sulfur and hydrogen, a cooler (40) connected to the reactor (1) for cooling an H2S-containing crude gas stream passed out of the reactor (1) to from 114 to 165° C., a vessel (42) which is connected to the cooler (40), comprises catalytically active material (41) and has a bottom (43) for collecting sulfur obtained from the crude gas stream comprising polysulfanes in the vessel (42) at from 114 to 165° C.

Abstract: The invention relates to a process and to an apparatus for preparing hydrogen sulfide H2S by converting a reactant mixture which comprises gaseous sulfur and hydrogen over a solid catalyst. The reactant mixture is converted at a pressure of from 0.5 to 10 bar absolute, a temperature of from 300 to 450° C. and a sulfur excess in a reactor (1). The sulfur excess corresponds to a ratio of excess sulfur to H2S prepared of from 0.2 to 3 kg of sulfur per kg of H2S prepared.

Abstract: The present invention relates to a process for the preparation of colorless, storage-stable polyisocyanates containing biuret groups from di- or polyisocyanates using water and/or steam as a biuretizing agent, and an apparatus for this purpose and the use thereof.