Covestro Deutschland Ag

Bayer Materialscience Ag

Bayer Intellectual Property Gmbh

Covestro Intellectual Property Gmbh & Co. Kg

Michael Merkel

Thomas Knauf

Peter Lehner

Tim Loddenkemper

Friedhelm Steffens

Andreas Karl Rausch

Norbert Eisen

Jürgen Münnig

Karl-Heinz Wilke

Manfred Kobylka

Cliff Andre Peters

Thorsten Schmidt

Martin Ehrig

Dominik Duerig

Bernhard Seidel

Rainer Bellinghausen

Amgad Salah Moussa

Antoni Mairata

Ralph Weber

Bastian Mahr

Frank Gerhartz

Erwin Dieterich

Andre Lago

Jan Morbach

Murat Kalem

Anna-Marie Zorn

Martin Schiffhauer

Maria Carrascosa Mas

Christian Morten Jens

Lutz Liebegott

Pascal Scherpian

Stefan Hirschfeld

Günter Gansen

Dominik DÜRIG

The present invention relates to a process for distillative purification of a crude isocyanate obtained by phosgenation of the corresponding amine in a distillation apparatus under vacuum to obtain the corresponding isocyanate, characterized in that at least one liquid ring compressor is used to generate the vacuum in the distillation apparatus, a particular operating liquid is used for the at least one liquid ring compressor, the pressure p on the suction side of the at least one liquid ring compressor is 10 to 200 mbar(a), the operating temperature of the at least one liquid ring compressor is −17° C. to +15° C. and the operating liquid at the exit from the at least one liquid ring compressor has an AC value of less than 35 000 ppm, to a corresponding use of at least one liquid ring compressor for generating a vacuum in an apparatus for distillation of a crude isocyanate and to a corresponding process for operating a liquid ring compressor for providing the vacuum for distillative purification of an isocyanate obtained by phosgenation of the corresponding amine in a distillation apparatus to obtain the corresponding isocyanate.

Process for the distillation of isocyanates

The invention relates to a method for preparing a suspension of a hydrochloride of an organic amine, comprising the following steps of (i) initially charging at least one organic solvent in a reaction vessel to form a liquid level, (ii) adding hydrogen chloride, (iii) adding the organic amine, wherein the organic amine is added below the liquid level present in the reaction vessel and steps (ii) and (iii) are at least partly carried out simultaneously. Furthermore, the present invention also relates to a method wherein the suspension obtained after step (iii) is reacted in a step (iv) with phosgene to obtain the organic isocyanate corresponding to the organic amine used, to the corresponding organic isocyanate and to the use of the organic isocyanate for producing polyisocyanates.

Method for preparing an amine hydrochloride suspension

The present invention relates to a bulk material comprising solid diisocyanate, especially naphthalene 1,5-diisocyanate or p-phenylene diisocyanate, to a process for production thereof, and to a process for preparing isocyanate prepolymers using the bulk material of the invention, to the isocyanate prepolymers themselves and to the use thereof for preparation of polyurethane elastomers, especially cast polyurethane elastomers.

Bulk material comprising solid diisocyanates and prepolymers containing urethane groups obtainable therefrom

Provided is a process for separating an organic isocyanate prepared by reacting an organic amine with a stoichiometric excess of phosgene in the gas phase from the gaseous crude product obtained in the reaction, the process comprising the steps of (i) at least partially condensing the crude product stream containing at least the isocyanate, hydrogen chloride and unconverted phosgene by contacting with at least one liquid stream containing at least one quench liquid in a first separation apparatus to obtain a liquid stream containing at least some of the quench liquid and some of the isocyanate and a gas stream containing at least hydrogen chloride, evaporated quench liquid and phosgene, (ii) discharging the liquid stream obtained in step (i) via a first liquid outlet and of the gas stream obtained in (i) via a first gas conduit and (iii) at least partially condensing and/or absorbing the gas stream discharged in step (ii) through the first gas conduit, wherein that the at least partial condensation and/or absorption is effected in step (iii) by direct introduction of at least one cooling fluid, wherein the cooling fluid is introduced directly into the first gas conduit via at least one addition unit assigned to the first gas conduit.

Process for separating an organic isocyanate

Provided is a process for preparing an organic diisocyanate of the formula: OCN&#x2014;R&#x2014;NCO (1), wherein R represents a bivalent hydrocarbon radical containing 3 to 20 carbon atoms, the carbon atoms being arranged in a way that the two nitrogen atoms are separated from each other by at least 3 carbon atoms, the process comprising, Step (I) preparing a diurethane of the formula wherein R is the same as in formula (1), R' and R&#x2033; independently represent organic radicals selected from the group consisting of 4 to 36 carbon atoms, 4 to 74 hydrogen atoms, 0 to 12 oxygen atoms that have the oxidation state &#x2212;2, and 0 to 1 halogen atoms from a diarylurethane of the formula, wherein R is the same as in formula (1), Ar and Ar&#x2032; independently represent a substituted or unsubstituted aryl or heteroaryl radical selected from the group containing a total of 4 to 20 carbon atoms by transesterification, Step (II) subjecting the diurethane of the formula (2) to a cleavage reaction to form the hydroxy compounds R&#x2032;&#x2014;OH and R&#x2033;&#x2014;OH and the organic diisocyanate of the formula (1), Step (III) separating the diisocyanate of the formula (1) from the hydroxy compounds R&#x2032;&#x2014;OH and R&#x2033;&#x2014;OH by distillation, wherein the hydroxy compounds R&#x2032;&#x2014;OH and R&#x2033;&#x2014;OH have higher standard boiling points than the standard boiling point of the diisocyanate OCN&#x2014;R&#x2014;NCO and the sum of the molecular weights of the radicals Ar and Ar&#x2032; is lower than the sum of the molecular weights of the radicals R&#x2032; and R&#x2033;.

Multistep process for the preparation of diisocyanates

The invention relates to a cleaning device for separating an organic isocyanate produced by the reaction of an organic amine with a stoichiometric excess of phosgene in the gas phase from the gaseous raw product obtained in the reaction, said device comprising a first separating body comprising at least one raw product supply line for a gaseous raw product flow containing at least the isocyanate, hydrogen chloride and non-reacted phosgene, a first liquid supply line for a liquid flow containing at least one quench liquid, and a first liquid discharge line for a liquid flow containing at least part of the quench liquid and part of the isocyanate, a first gas line for transporting a gas flow containing at least hydrogen chloride, evaporated quench liquid and phosgene leading away from the first separating body. The invention is characterized in that at least one addition body for directly introducing at least one cooling fluid for an at least partial condensation and/or absorption of the gas flow that can be guided via the first gas line is associated with the first gas line.

Cleaning device for gas flows from isocyanate production

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 mbarto 500 mbar, and wherein from each of the first distillation column and the second distillation column, (i) a gaseous aniline distillate (=purified aniline) is removed as the overhead product and subsequently condensed, wherein a first partial stream of the condensed aniline distillate is returned to the first and/or the second distillation column as a reflux stream and a second partial stream of the condensed aniline distillate is removed as the product stream, and (ii) a liquid bottom stream which is concentrated in phenol is removed, from which a first portion is partially or completely vaporised and is returned to the respective distillation column, and from which a second portion is discharged; d) using the heat released during the condensation of the aniline distillate from the first distillation column in order to provide the heat necessary for vaporising the first portion of the bottom stream from the second distillation column.

Aniline purification process

The present invention relates to a method for producing purified phosgene vapor, comprising the following steps: 1) providing a gas flow obtainable from the reaction of chlorine with carbon monoxide and comprising phosgene and carbon monoxide; 2) one-stage or multi-stage condensation of the gas flow and separation of non-condensable residue gases; 3) one-stage or multi-stage evaporation of the liquid phosgene obtained in step 2) and optional overheating of the produced phosgene vapour, wherein there is an energy integration between one or more of the condensation steps of step 2) and one or more of the evaporation steps in step 3) and the pressure in the last condensation step is between &#x2265;0.2 and &#x2264;6.0 bar higher than in the first evaporation step.

Energy-efficient method for providing a purified phosgene vapor

The present invention relates to a method for treating a substance mixture comprising an aromatic amine, wherein the aromatic amine is aniline or 2,4-diaminotoluene, preferably aniline. The substance mixture comprises an aromatic amine and compounds having a higher boiling point than the aromatic amine. The method for treating the substance mixture requires I) separating the first substance mixture by means of distillation in a first distillation unit (), to at least partially remove some of the aromatic amine in the process, and to obtain a first bottom product which is removed from the first distillation unit (). After removal from the first distillation unit (), the bottom product is diluted with a condensed top product from a distillation unit that is different from the first distillation unit and/or with a composition that comprises methanol.

Method for treating a substance mixture comprising an aromatic amine, in particular a substance mixture of raw aniline

The present invention relates to a method for producing aromatic amines by the hydrogenation of aromatic nitro compounds. This method supplies aromatic nitro compounds and hydrogen to a reactor and contacts them with a hydrogenation catalyst; and stops the supply of aromatic nitro compounds and hydrogen to the reactor. The supply of aromatic nitro compounds and hydrogen to the reactor is stopped to ensure safe shutdown of the reactor.

Method for stopping a reaction during the production of aromatic amines from nitroaromatics

The present invention relates to a process for the purification of aniline which originates from gas phase hydrogenations. In this process, only a minimum proportion of the aniline has to be evaporated and condensed again. The process is highly efficient in removing compounds which have phenolic hydroxyl groups and results in minimal losses of aniline. This process also reduces the unwanted coupling mechanisms in the division of the overall crude product in the fraction condensation into individual substreams and the subsequent workup of these.

Process for the purification of aniline from gas phase hydrogenations

In a chemical reactor for heterogeneously catalyzed reaction of a fluid, comprising a holding device for catalyst particles and/or inert particles () through which the fluid flows, the side of the holding device lying upstream when viewed in the direction of flow of the fluid comprises knitted wire mesh fabric (), and the average clear mesh width of the knitted wire fabric () is smaller than the average particle size xof the particles (). The invention furthermore relates to a process for reaction of a fluid, wherein the reaction is carried out in a reactor according to the invention in the presence of heterogeneous catalyst particles () and the catalyst particles () are arranged in the holding device for catalyst particles (). The invention also provides the use of knitted wire mesh fabric () as a holding device for catalyst particles and/or inert particles () in chemical reactors.

Chemical reactor with knitted wire mesh fabric as a holding device for particles

The present invention relates to a method of producing aromatic amines by hydrogenation of aromatic nitro compounds. This method provides a reactor containing a hydrogenation catalyst; supplies aromatic nitro compounds and hydrogen to the reactor and contacts them with a hydrogenation catalyst, in which the hydrogen which is supplied to the reactor is by a compressor and the compressor contains an operating fluid which at least partially contacts the hydrogen; and regenerates the hydrogenation catalyst by heating and contacting it with oxygen. Particular operating liquids are subsequently exchanged.

Method for starting a reaction during the production of aromatic amines from nitroaromatics

The present invention provides a continuous process for the production of nitrobenzene by nitration of benzene with mixtures of sulfuric and nitric acid using a stoichiometric excess of benzene, in which the content of aliphatic organic compounds in the feed benzene during the start-up period of the production plant is always maintained at less than 1.5 wt. %, based on the total mass of the feed benzene. This is achieved either by mixing the feed benzene comprising recycled unreacted benzene (recycled benzene) and benzene newly supplied to the reaction (fresh benzene) in appropriate quantitative ratios during the start-up period, depending on the purity of the two streams, or by completely omitting the recycling of unreacted benzene during the start-up period, i.e. the feed benzene consists only of benzene newly supplied to the reaction.

Process for the production of nitrobenzene by adiabatic nitration

The present invention relates to a catalyst comprising a ceramic support with a BET surface area of less than 40 m/g and (a) 1.0 to 100 g of at least one metal of groups 8 to 12 of the periodic table of the elements, (b) 1.0 g to 100 g of at least one metal of groups 4 to 6 and 12 of the periodic table of the elements and (c) 1.0 g to 100 g of at least one metal of groups 14 and 15 of the periodic table of the elements per liter of bulk volume of the ceramic support, wherein the catalyst is additionally doped with (d) potassium in a content of from 0.0050% by weight to 0.20% by weight, based on the total weight of the catalyst. The present invention also provides the use of such a catalyst in the catalytic gas phase hydrogenation of nitroaromatics.

Growing community of inventors

Düsseldorf, Germany

Michael Merkel