Abstract:
The invention relates to a method for partially or completely separating a substance mixture consisting of hydrogen chloride and phosgene, optionally of solvents and optionally of low-boiling fractions and inert substances such as those that normally arise during the production of isocyanates by reacting amines with phosgene. The inventive method is characterized in that a partial or complete condensation of phosgene is firstly carried out followed by a distillation or stripping inside a column for removing the hydrogen chloride from the bottom product phosgene and lastly, a washing of the top product hydrogen chloride with the process solvent for absorbing the phosgene in the process solvent is carried out. A subsequent purification by means of adsorption on activated carbon or other appropriate methods can be used for removing solvent remnants.
Abstract:
The invention relates to a method for producing isocyanates by reacting amines with phosgene inside a reactor followed by separating the isocyanate out from the reaction mixture exiting the reactor and purifying this isocyanate. The invention is characterized in that the isocyanate is separated out and purified in a column with a top pressure of 1 to 950 mbar, preferably 5 to 50 mbar, particularly preferred 10 to 20 mbar, with a bottom temperature of 90 to 250 °C, preferably 120 to 170 °C, particularly preferred 130 to 150 °C, and that the pure isocyanate flow is withdrawn in liquid or gaseous form, preferably in a side-stream of the column.
Abstract:
Disclosed is a method for aminating hydrocarbons with ammonia. Said method is characterized in that the amination process is carried out in the presence of an additive which reacts with hydrogen. At least one organic-chemical compound, N2O, hydroxylamine, hydrazine, and/or carbon monoxide is/are used as an additive.
Abstract:
Disclosed is a method for aminating hydrocarbons with ammonia. Said method is characterized in that the N2 concentration in the mixture at the reactor outlet is less than 0.1 percent by volume relative to the total volume of the mixture at the reactor outlet (Formula (I)).
Abstract:
The invention relates to a method for converting aromatic nitro compounds into the corresponding amines in the presence of hydrogenation catalysts. Said method is characterized in that hydrogenation catalysts are used in which nickel and platinum are provided on a carrier in the form of an alloy, the atomic ratio between nickel and platinum in said alloy ranging between 30:70 and 70:30.
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 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.