Abstract: The invention relates to a process for the partial or complete separation of a mixture comprising hydrogen chloride and phosgene, possibly solvents and possibly low boilers and inerts as are typically obtained in the preparation of isocyanates by reaction of amines with phosgene, which comprises firstly carrying out a partial or complete condensation of phosgene, then a distillation or stripping step in a column to remove the hydrogen chloride from the bottom product phosgene and subsequently a scrub of the top product hydrogen chloride by means of the process solvent to absorb the phosgene in the process solvent. An after-purification by means of adsorption on activated carbon or by another suitable method can subsequently be carried out to remove solvent residues.

Abstract: The invention relates to a process for preparing isocyanates by reaction of amines with phosgene in the presence of inert organic solvents in a reactor and subsequent work-up of the reaction mixture leaving the reactor, wherein the solvent is separated off in a two-stage or multistage, preferably two-stage, distillation process in which the solvent is separated off at a pressure of 0.1-15 bar in a first apparatus and at 1-900 mbar in a second apparatus or further apparatuses, with the heat of condensation of the solvent vapor from the first apparatus being used for partial or complete vaporization of solvent in the second apparatus.

Abstract: A process is described for preparing diaminodiarylmethanes comprising the steps a) reacting an aromatic amine with a methylene-donating agent in the presence of homogeneous acid catalysts, b) removing the homogeneous acid catalyst from the reaction product, c) working up and purifying the reaction product, which comprises removing the homogeneous acid catalyst from the reaction mixture by adsorption to a solid adsorbent.

Abstract: Process for preparing organic isocyanates, which comprises the steps (a) making available a first partial amount of chlorine, with the chlorine of this first partial amount having a content of free and bound bromine and iodine of <400 ppm; (b) making available a second partial amount of chlorine; (c) reacting the first and second partial amounts of chlorine with carbon monoxide to form phosgene; (d) reacting the phosgene from step (c) with one or more primary amines to form the corresponding isocyanates and hydrogen chloride; (e) separating off and, if necessary, purifying the isocyanates formed in step (d); (f) separating off and, if necessary, purifying the hydrogen chloride formed in step (d); (g) catalytically oxidizing at least part of the hydrogen chloride separated off in step (e) by means of oxygen to form chlorine; (h) separating off the chlorine formed in step (g) and using at least a partial amount of the chlorine which has been separated off as second partial amount of chlorine in step (b).

Abstract: Process for preparing organic isocyanates, which comprises the steps