Abstract: Disclosed is a process for purifying propylene oxide. A stream S0 containing propylene oxide, acetonitrile, water, and an organic compound containing one or more of acetone and propionaldehyde is provided. Propylene oxide is separated from S0 by subjecting S0 to distillation in a first distillation unit, obtaining a gaseous top stream S1c enriched in propylene oxide, a liquid bottom stream S1a enriched in acetonitrile and water, and a side stream S1b containing propylene oxide and enriched in the carbonyl compound; reacting the carbonyl compound in S1b with an organic compound containing an amino group to obtain a reaction product; separating propylene oxide from the reaction product in a second distillation unit, obtaining a gaseous top stream S3a enriched in propylene oxide and a liquid bottoms stream S3b enriched in the reaction product; and introducing stream S3a into the first distillation unit.

Abstract: A continuous process for the preparation of propylene oxide, comprising a start-up stage and normal run stage, wherein the normal run stage comprises (i) continuously providing a liquid feed stream comprising propene, hydrogen peroxide, acetonitrile, a formate salt, water and optionally propane, wherein in the liquid feed stream, the molar amount of the formate salt relative to the molar amount of hydrogen peroxide at a given point of time during the normal run stage is aN(Fo/H2O2); (ii) continuously passing the liquid feed stream provided in (i) into an epoxidation zone comprising a catalyst comprising a titanium zeolite having framework type MWW, and subjecting the liquid feed stream to epoxidation reaction conditions in the epoxidation zone, obtaining a reaction mixture comprising propylene oxide, acetonitrile, water, the formate salt, optionally propene, and optionally propane; (iii) continuously removing an effluent stream from the epoxidation zone, the effluent stream comprising propylene oxide, acetoni

Abstract: Disclosed is a process for purifying propylene oxide. A stream S0 containing propylene oxide, acetonitrile, water, and an organic compound containing one or more of acetone and propionaldehyde is provided. Propylene oxide is separated from S0 by subjecting S0 to distillation in a first distillation unit, obtaining a gaseous top stream S1c enriched in propylene oxide, a liquid bottom stream S1a enriched in acetonitrile and water, and a side stream S1b containing propylene oxide and enriched in the carbonyl compound; reacting the carbonyl compound in S1b with an organic compound containing an amino group to obtain a reaction product; separating propylene oxide from the reaction product in a second distillation unit, obtaining a gaseous top stream S3a enriched in propylene oxide and a liquid bottoms stream S3b enriched in the reaction product; and introducing stream S3a into the first distillation unit.

Abstract: The present invention is related to a process for preparing propylene oxide, comprising (i) providing a stream comprising propene, hydrogen peroxide or a source of hydrogen peroxide, water, and an organic solvent; (ii) passing the liquid feed stream provided in (i) into an epoxidation zone comprising an epoxidation catalyst comprising a titanium zeolite, and subjecting the liquid feed stream to epoxidation reaction conditions in the epoxidation zone, obtaining a reaction mixture comprising propene, propylene oxide, water, and the organic solvent; (iii) removing an effluent stream from the epoxidation zone, the effluent stream comprising propylene oxide, water, organic solvent, and propene; (iv) separating propene from the effluent stream by distillation, comprising (iv.

Abstract: The present invention is related to a process for preparing propylene oxide, comprising (i) providing a stream comprising propene, hydrogen peroxide or a source of hydrogen peroxide, water, and an organic solvent; (ii) passing the liquid feed stream provided in (i) into an epoxidation zone comprising an epoxidation catalyst comprising a titanium zeolite, and subjecting the liquid feed stream to epoxidation reaction conditions in the epoxidation zone, obtaining a reaction mixture comprising propene, propylene oxide, water, and the organic solvent; (iii) removing an effluent stream from the epoxidation zone, the effluent stream comprising propylene oxide, water, organic solvent, and propene; (iv) separating propene from the effluent stream by distillation, comprising (iv.

Abstract: The invention relates to a method of separating a phosgene- and hydrogen chloride-comprising stream (5), wherein said method comprises conveying the hydrogen chloride- and phosgene-comprising stream (5) into a distillation column (1), withdrawing at the bottom of the distillation column (1) a phosgene-comprising stream (7) and withdrawing at the top of the column an essentially hydrogen chloride-comprising stream (9). At least a portion of the stream (9) withdrawn at the top is compressed and at least partially condensed and at least a portion of the liquid and compressed essentially hydrogen chloride-comprising stream is decompressed and recycled into the top of distillation column (1) as reflux.

Abstract: A continuous process for the preparation of propylene oxide, comprising a start-up stage and normal run stage, wherein the normal run stage comprises (i) continuously providing a liquid feed stream comprising propene, hydrogen peroxide, acetonitrile, a formate salt, water and optionally propane, wherein in the liquid feed stream, the molar amount of the formate salt relative to the molar amount of hydrogen peroxide at a given point of time during the normal run stage is aN(Fo/H2O2); (ii) continuously passing the liquid feed stream provided in (i) into an epoxidation zone comprising a catalyst comprising a titanium zeolite having framework type MWW, and subjecting the liquid feed stream to epoxidation reaction conditions in the epoxidation zone, obtaining a reaction mixture comprising propylene oxide, acetonitrile, water, the formate salt, optionally propene, and optionally propane; (iii) continuously removing an effluent stream from the epoxidation zone, the effluent stream comprising propylene oxide, acetoni

Abstract: The invention relates to a method of separating a phosgene- and hydrogen chloride-comprising stream (5), wherein said method comprises conveying the hydrogen chloride- and phosgene-comprising stream (5) into a distillation column (1), withdrawing at the bottom of the distillation column (1) a phosgene-comprising stream (7) and withdrawing at the top of the column an essentially hydrogen chloride-comprising stream (9). At least a portion of the stream (9) withdrawn at the top is compressed and at least partially condensed and at least a portion of the liquid and compressed essentially hydrogen chloride-comprising stream is decompressed and recycled into the top of distillation column (1) as reflux.

Abstract: The present invention relates to gas phase phosgenation of amines for preparation of isocyanates. In the present invention, phosgene is prepared by reacting chlorine with an excess of carbon monoxide in a gas phase. The obtained phosgene-containing reaction mixture is divided into two streams by a thermal and/or a membrane separating process. The first stream is a low-carbon monoxide stream of no more than 1% by weight of carbon monoxide, based on a total weight of the first stream. The second stream is a carbon monoxide-rich stream of more than 10% by weight of carbon monoxide, based on a total weight of the second stream. The first stream is used as the phosgene-containing reactant stream in the gas phase phosgenation of amines to prepare isocyanates. The second stream can be recycled into the phosgene synthesis.

Abstract: A process for preparing phosgene by reaction of a feed stream (1) obtained by combining and mixing a chlorine feed stream (2) and a carbon monoxide feed stream (3), with the carbon monoxide being introduced in a stoichiometric excess over chlorine, in catalyst tubes filled with beds of activated carbon in a reactor R having a bundle of catalyst tubes, to give a product gas mixture (4) which is separated into a liquid, phosgene-comprising product stream (5) and an offgas stream (6) comprising carbon monoxide which is discharged via a pressure-regulating valve, where the reaction of the feed stream (1) in the reactor R and the separation of the product gas mixture (4) are carried out under a pressure in the range from 2.0 to 6.

Abstract: The present invention relates to gas phase phosgenation of amines for preparation of isocyanates. In the present invention, phosgene is prepared by reacting chlorine with an excess of carbon monoxide in a gas phase. The obtained phosgene-containing reaction mixture is divided into two streams by a thermal and/or a membrane separating process. The first stream is a low-carbon monoxide stream of no more than 1% by weight of carbon monoxide, based on a total weight of the first stream. The second stream is a carbon monoxide-rich stream of more than 10% by weight of carbon monoxide, based on a total weight of the second stream. The first stream is used as the phosgene-containing reactant stream in the gas phase phosgenation of amines to prepare isocyanates. The second stream can be recycled into the phosgene synthesis.

Abstract: The present invention relates to gas phase phosgenation of amines for preparation of isocyanates. In the present invention, phosgene is prepared by reacting chlorine with an excess of carbon monoxide in a gas phase. The obtained phosgene-containing reaction mixture is divided into two streams by a thermal and/or a membrane separating process. The first stream is a low-carbon monoxide stream of no more than 1% by weight of carbon monoxide, based on a total weight of the first stream. The second stream is a carbon monoxide-rich stream of more than 10% by weight of carbon monoxide, based on a total weight of the second stream. The first stream is used as the phosgene-containing reactant stream in the gas phase phosgenation of amines to prepare isocyanates. The second stream can be recycled into the phosgene synthesis.

Abstract: The invention relates to a process for preparing methylenedi(phenyl isocyanate), which comprises (a) the phosgenation of two-ring and/or multiring methylenedi(phenylamine), (b) the fractionation of the crude methylenedi(phenyl isocyanate) obtained to give two-ring and multiring isomers, (c) the purification and/or fractionation of the resulting mixture of two-ring isomers of methylenedi(phenyl isocyanate) and (d) the storage of the mixtures obtained in step (c) or in step (b), wherein part of the stored mixtures is reused by means of recirculation in at least one of steps (b) or (c).

Abstract: Processes for preparing 4-chlorobenzenesulfonic acid from 2-chlorobenzenesulfonic acid and/or 3-chlorobenzenesulfonic acid, which processes include the conversion of 2-chlorobenzenesulfonic acid and/or 3-chlorobenzenesulfonic acid to 4-chlorobenzenesulfonic acid in the presence of sulfuric acid at a temperature of 100 to 300° C.; as well as processes for preparing 4,4?-dichlorodiphenyl sulfone, which include such described processes for preparing 4-chlorobenzenesulfonic acid.

Abstract: The present invention relates to a process for preparing an isocyanate, comprising hydrogenating a mixture (Gi) comprising an amine in the presence of a hydrogenation catalyst comprising copper to obtain a mixture (Gii) comprising the amine, and reacting the mixture (Gii) with phosgene to obtain a mixture (Giii) comprising the isocyanate. The present invention further relates to the isocyanate preparable by this process.

Abstract: The present invention accordingly provides a process for preparing light-colored polyphenylene-polymethylene polyisocyanates comprising the steps (a) providing an amount of chlorine, (b) separating the chlorine provided in the step (a) to obtain a first chlorine fraction having a content of free and bound bromine and iodine of <50 ppm and a second chlorine fraction having an increased content of free and bound bromine and iodine that depends on the original amount of bromine and iodine in the chlorine provided in step (a) and the separation split, (c) reacting carbon monoxide with at least a portion of the first chlorine fraction to form a first phosgene fraction, (d) reacting carbon monoxide with at least a part of the second chlorine fraction to form a second phosgene fraction, (e) reacting at least a portion of a first phosgene fraction with at least one amine of the diphenylmethane diamine series (MDA) to form the corresponding polyphenylene-polymethylene polyisocyanate (PMDI), and (f) reacting at leas

Abstract: The present invention relates to a process for the production of isocyanates, preferably diisocyanates and polyisocyanates of the diphenylmethane series (MDI), by reacting an amine with phosgene in the liquid phase or in the gas phase to form the corresponding isocyanates, subsequent removal of the solvent in at least two steps to obtain at least two solvent streams, individual treatment of the at least two solvent streams, and recirculation of at least a portion of the solvent streams.

Abstract: The present invention relates to a process for preparing light-colored polyphenylene-polymethylene-polyisocyanate (PMDI), comprising the steps (a) providing carbon monoxide and chlorine, (b) reacting carbon monoxide with chlorine to form phosgene, (c) reacting the phosgene from step (b) with at least one primary amine with the exception of mono- and polyphenylene-polymethylene polyamines with an excess of phosgene to form an at least one isocyanate containing reaction solution, and hydrogen chloride, (d) separating excess phosgene from the isocyanate-containing reaction solution obtained in step (c), (e) providing at least one polyphenylene-polymethylene polyamine, and (f) reacting at least a portion of the phosgene separated in step (d) with the at least one polyphenylene-polymethylene polyamine to form the light-colored polyphenylene-polymethylene polyisocyanate.

Abstract: A process for preparing diisocyanates by gas-phase phosgenation starting out from a feed stream comprising the corresponding diamines and a phosgene-comprising feed stream, in which the feed streams are separately converted into the gas phase and preheated to the reaction temperature of the gas-phase phosgenation, wherein the waste heat from a plant for preparing chlorine by heterogeneously catalyzed oxidation of hydrogen chloride by the Deacon process is utilized for this purpose, is proposed.

Abstract: The invention relates to a process for preparing methylenediphenyldiamine (MDA) by reacting formaldehyde and aniline in the presence of an acidic catalyst, wherein the oxygen content in the process for preparing MDA is <10 000 ppm, based on all compounds present in the process. The invention further relates to the phosgenation of MDA to methylenediphenyl diisocyanate (MDI).