Abstract:
The invention relates to a method for producing isocyanates and/or polyisocyanates by reacting the corresponding amines with phosgene, optionally in the presence of an inert medium, in a reactor (1), wherein a first reactant stream containing the amine is fed to the reactor (1) in liquid form and a second reactant stream containing the phosgene is fed to the reactor in gaseous form. The reactor is a centrifugal reactor (1), which has a packing (9) rotating about a central axis (7) in a housing (13), the first reactant stream and the second reactant stream being fed to the rotating packing (9) in such a manner that the reactant streams are mixed and transported outward by the centrifugal force in the rotating packing (9), wherein the phosgene reacts with the amine due to the mixing in the rotating packing (9) to form the corresponding isocyanate or polyisocyanate.
Abstract:
The present invention relates to a process for preparing polyisocyanates from natural raw material sources by starting from a biomass material and preparing a composition which comprises low molecular mass aromatics that contain per molecule at least one hydroxyl group or at least one alkoxy group (oxyaromatics), reacting these oxyaromatics to form the corresponding aromatic amines, and, optionally after condensation with formaldehyde, carrying out further reaction with phosgene to form compounds containing isocyanate groups.
Abstract:
The invention relates to a method for producing isocyanates through reaction of the corresponding amines with phosgene in the liquid phase, optionally in the presence of at least one inert medium, in which first the amine and the phosgene are mixed in a mixing chamber (1) to form a reaction mixture and the reaction mixture is fed to a reactor, wherein the amine is added through an opening (3) that is disposed coaxially to the mixing chamber (1) and wherein the phosgene is added through feed openings (5) in at least two planes (7, 9) disposed perpendicular to the axis (11) of the mixing chamber (1), or the phosgene is added through the opening (3) that is coaxial to the mixing chamber and the amine is added through the feed openings (5) in at least two planes (7, 9) disposed perpendicular to the axis (11) of the mixing chamber (1). At least one plane (9) is disposed upstream in the main flow direction of the reaction mixture and at least one plane (7) is disposed downstream relative to the opening (3) disposed coaxially to the mixing chamber (1). The average residence time of the reaction mixture in the mixing chamber (1) is no more than 20 ms.
Abstract:
The invention relates to a method for producing methylene diphenyl diamine (MDA) by reacting formaldehyde and aniline in the presence of an acidic catalyst, characterized in that in the production of MDA, the oxygen content in the process is
Abstract:
The invention relates to a method for producing methylene diphenyl diamine (MDA) comprising the following steps a) to c): a) converting formaldehyde and aniline to an aminal, (b) removing water from the aminal obtained in step a), wherein a water content of 0 to 5 wt. % based on the aminal is set, and c) adding an acid catalyst to the aminal with a water content of 0 to 5 wt. %, characterized in that in step a) formaldehyde is used as a highly concentrated formaldehyde with a CH 2 O content > 50 wt. % and the formaldehyde is produced by the oxidative dehydrogenation of methanol.
Abstract:
The invention relates to a method for producing mononitro aromatic compounds and dinitro aromatic compounds wherein a hydrate melt at least of a metal nitrate M(NO 3 ) 3 is used as a nitriding medium, wherein M can be the metals Fe, Cr, Y, La, Ce, AI, Bi and In, and wherein the metal nitrate has a water content of between 4 to 9 mol water per M(NO 3 ) 3 , leading to process simplifications and improved yield.