Abstract: The invention relates to a method for the purification of aniline, comprising the following steps: a) providing a raw aniline fraction; b) extracting the raw aniline fraction with an aqueous extractant containing, in relation to the total mass of the aqueous extractant, an alkali metal hydroxide in a concentration range from 0.009 to 2.05 mass % and an alkali metal salt that is different from an alkali metal hydroxide in a concentration range from 2.40 to 25.0 mass %, wherein an organic aniline phase and an aqueous amino phenolate phase are obtained after a phase separation; c) distilling the organic aniline phase from step b), obtaining a flow of purified aniline, a gaseous flow that boils at a lower temperature than aniline and containing organic impurities, and a liquid flow that boils at a higher temperature than aniline and containing organic impurities and aniline.

Abstract: The invention relates to a method for recovering raw materials from polyurethane products, comprising the steps of (A) providing a polyurethane product that is based on an isocyanate component and a polyol component; (B) reacting the polyurethane product with a (mono- or polyvalent) alcohol in the presence of a catalyst, thereby obtaining a first product mixture; (C) obtaining the polyols from the first product mixture, comprising (C.I) mixing, without prior removal of any water that might be contained in the first product mixture, the first product mixture obtained in step (B) with an organic solvent that is not completely miscible with the alcohol used in step (B), and phase separation into a first alcohol phase and a first solvent phase; (C.II) processing the first solvent phase and obtaining polyols; and preferably (D) obtaining amines.

Abstract: The present invention relates to a process for recovering raw materials from a polyurethane foam, comprising step (A), the providing of a polyurethane foam based on an isocyanate component and a polyol component, wherein the polyurethane foam comprises a cell structure containing one or more volatile accompanying substances, namely a component X selected from the group consisting of oxygen, a blowing agent, a disinfectant and a mixture of two or more of the above, wherein component X comprises at least oxygen, step (B), the chemolysis of the polyurethane foam with a chemolysis reagent, wherein the polyurethane foam is degassed before being contacted with the chemolysis reagent, wherein at least oxygen, but preferably all constituents of component X or any gaseous breakdown products thereof that have formed are removed from the chemolysis apparatus in gaseous form via a gas removal device at a pressure of not more than 960 mbar(abs.) and a temperature of not more than 120° C.

Abstract: The invention relates to a method for recovering raw materials from polyurethane products, having the steps of: (A) providing a polyurethane product based on an isocyanate component and a polyol component; (B) reacting the polyurethane product with an alcohol in the presence of a catalyst, wherein a first product mixture containing alcohol, polyols, carbamates, and optionally water is obtained; (C) preparing the first product mixture, having the steps of: (C.I.) mixing the first product mixture obtained in step (B) with an organic solvent, which can be mixed with the alcohol used in step (B), optionally followed by a separation of solid components, thereby obtaining a second product mixture; (C.II) washing the second product mixture obtained in step (C.

Abstract: The invention relates to a method for the purification of aniline, comprising the following steps: a) providing a raw aniline fraction; b) extracting the raw aniline fraction with an aqueous extractant containing, in relation to the total mass of the aqueous extractant, an alkali metal hydroxide in a concentration range from 0.009 to 2.05 mass % and an alkali metal salt that is different from an alkali metal hydroxide in a concentration range from 2.40 to 25.0 mass %, wherein an organic aniline phase and an aqueous amino phenolate phase are obtained after a phase separation; c) distilling the organic aniline phase from step b), obtaining a flow of purified aniline, a gaseous flow that boils at a lower temperature than aniline and containing organic impurities, and a liquid flow that boils at a higher temperature than aniline and containing organic impurities and aniline.

Abstract: The invention relates to a method for recovering raw materials from polyurethane products, comprising the steps of (A) providing a polyurethane product that is based on an isocyanate component and a polyol component; (B) reacting the polyurethane product with a (mono- or polyvalent) alcohol in the presence of a catalyst, thereby obtaining a first product mixture; (C) obtaining the polyols from the first product mixture, comprising (C.I) mixing, without prior removal of any water that might be contained in the first product mixture, the first product mixture obtained in step (B) with an organic solvent that is not completely miscible with the alcohol used in step (B), and phase separation into a first alcohol phase and a first solvent phase; (C.II) processing the first solvent phase and obtaining polyols; and preferably (D) obtaining amines.

Abstract: The present invention relates to a method and a system for separating and treating impurities from a hydrogen chloride liquid mixture from the process for preparing isocyanate with phosgenation including sending hydrogen chloride liquid mixture into a gas-liquid separation column for separation to yield a liquid phase flow with impurities at the bottom of the gas-liquid separation column, neutralizing the liquid phase flow comprising impurities with an alkaline liquid in the neutralization tank to yield a neutralized solution, and sending the neutralized solution into a waste liquid treatment device from said neutralization tank for treatment.

Abstract: The present invention relates to a distributor device (10000) for the even distribution of a fluid (10) into 2 or more fluid streams each containing gas (11) and liquid (12), with a falling film evaporator (100000), in which the distributor device according to the invention serves to distribute the 2 or more fluid streams onto the heating pipes of the evaporator, and to the use of the distributor device (10000) according to the invention and in particular the falling film evaporator (100000) according to the invention in the production and/or preparation of chemical products. The distributor device according to the invention is characterized, in particular, by a swirl breaker (600) for the gas phase (11) which arises from separating the fluid (10) into a gas phase (11) and a liquid phase (12) within the distributor device.

Abstract: The present invention concerns a process for the preparation of pure aniline, comprising the steps of a) providing a crude aniline fraction containing up to 20.000% by weight of phenol; b) dividing the crude aniline fraction from step a) into a first partial stream and a second partial stream; c) distilling the first partial stream from step b) in a first distillation column and distilling the second partial stream from step b) in a second distillation column, wherein the first distillation column is operated at a higher head pressure than the second distillation column, with the proviso that each of the first distillation column and the second distillation column is operated at a head pressure in the range from 1.0 mbar(abs.) to 500 mbar(abs.

Abstract: The invention relates to a novel method for producing polyisocyanurates comprising isocyanate groups, based on 2,4- and 2,6-toluylene diisocyanate (TDI) and to the use thereof in coating compositions.

Abstract: The present invention concerns a process for the preparation of pure aniline, comprising the steps of a) providing a crude aniline fraction containing up to 20.000% by weight of phenol; b) dividing the crude aniline fraction from step a) into a first partial stream and a second partial stream; c) distilling the first partial stream from step b) in a first distillation column and distilling the second partial stream from step b) in a second distillation column, wherein the first distillation column is operated at a higher head pressure than the second distillation column, with the proviso that each of the first distillation column and the second distillation column is operated at a head pressure in the range from 1.0 mbar(abs.) to 500 mbar(abs.

Abstract: A distillation column for separating a multicomponent mixture into at least three fractions. The distillation column has at least one separating wall and at least one material exchange element (1) above the at least one separating wall. A device (10) for mixing the steam flows flowing upwards to the left and the right of the at least one separating wall is arranged between the at least one separating wall and the at least one material exchange element (1). The use of the distillation column for purifying isocyanates, in particular for toluene diisocyanate (TDI), is also described.

Abstract: The invention relates to the production of isocyanates by means of phosgenation of the corresponding primary amines in the gas phase, wherein the reactant flows of amine and phosgene are fed separately to a reactor through a pre-heated inert gas flow. Isocyanates within the sense of the invention are, in the broadest sense, all isocyanates whose corresponding amines can be substantially converted into the gas phase without decomposing, with the exception of 1,5-pentane diisocyanate.

Abstract: A method for producing isocyanates by reacting primary amines with phosgene in a stoichiometric excess in the gas phase, wherein the excess phosgene is subsequently recovered and recirculated back into the reaction. particular a method for the feedback-controlled recirculation of the recovered phosgene, particularly when the phosgene stream that should be recovered is distributed between multiple gas-phase reactors operated in parallel.

Abstract: The invention relates to a novel method for producing polyisocyanurates comprising isocyanate groups, based on 2,4- and 2,6-toluylene diisocyanate (TDI) and to the use thereof in coating compositions.

Abstract: The invention relates to polyisocyanates comprising urethane groups, based on toluylene diisocyanate, to a method for their production, and to their use as the polyisocyanate component in one- and two-component polyurethane coatings.

Abstract: The invention relates to the production of isocyanates by means of phosgenation of the corresponding primary amines in the gas phase, wherein the reactant flows of amine and phosgene are fed separately to a reactor through a pre-heated inert gas flow. Isocyanates within the sense of the invention are, in the broadest sense, all isocyanates whose corresponding amines can be substantially converted into the gas phase without decomposing, with the exception of 1,5-pentane diisocyanate.

Abstract: One or more fluid streams are uniformly divided into two or more partial fluid streams in chemical apparatuses in a manner such that there is a reduced tendency to form deposits. Division of such stream(s) is achieved by using a distributor device that includes at least one plate having two or more openings which openings are rounded or chamfered on at least one side.

Abstract: The invention relates to a novel method for producing polyisocyanurates comprising isocyanate groups, based on 2,4- and 2,6-toluylene diisocyanate (TDI) and to the use thereof in coating compositions.

Abstract: The invention relates to a distillation column for separating a multicomponent mixture into at least three fractions. The distillation column has at least one separating wall and at least one material exchange element (1) above the at least one separating wall. A device (10) for mixing the steam flows flowing upwards to the left and the right of the at least one separating wall is arranged between the at least one separating wall and the at least one material exchange element (1). The invention likewise relates to the use of the distillation column according to the invention for purifying isocyanates, in particular for toluene diisocyanate (TDI).