Abstract: Processes for the production of chlorine by multi-stage oxidation, for example, by thermal reaction of hydrogen chloride with oxygen using catalysts or by non-thermal activated reaction of hydrogen chloride with oxygen, in which the gas mixture formed in the reaction, comprising the target products chlorine and water, unreacted hydrogen chloride and oxygen, and possibly other secondary constituents, such as carbon dioxide and nitrogen, (a) is cooled to condense hydrochloric acid as an aqueous solution of hydrogen chloride and (b) the aqueous solution of hydrogen chloride formed is separated from the gas mixture, characterised in that (c) the separated aqueous solution of hydrogen chloride is fed at least partially to an electrochemical oxidation in which at least part of the hydrogen chloride is oxidised to chlorine, (d) the chlorine gas occurring in step d) is optionally added to the gas mixture occurring in step c), (e) the residues of water present in the gas mixture from steps c) and e), in particular by

Abstract: An isocyanate is produced by: (a) reacting chlorine with carbon monoxide to form phosgene, (b) reacting the phosgene with an organic amine to form an isocyanate and hydrogen chloride, (c) separating the isocyanate and hydrogen chloride, (d) optionally, purifying the hydrogen chloride, (e) preparing an aqueous solution of the hydrogen chloride, (f) optionally, purifying the aqueous solution of hydrogen chloride, (g) subjecting the aqueous hydrogen chloride solution to electrochemical oxidation to form chlorine, and (h) returning at least a portion of the chlorine produced in (g) to (a).

Abstract: An isocyanate is produced by: (a) reacting chlorine with carbon monoxide to form phosgene, (b) reacting the phosgene with an organic amine to form an isocyanate and hydrogen chloride, (c) separating the isocyanate and hydrogen chloride, (d) optionally, purifying the hydrogen chloride, (e) preparing an aqueous solution of the hydrogen chloride, (f) optionally, purifying the aqueous solution of hydrogen chloride, (g) subjecting the aqueous hydrogen chloride solution to electrochemical oxidation to form chlorine, and (h) returning at least a portion of the chlorine produced in (g) to (a).

Abstract: Processes for the production of chlorine by multi-stage oxidation, for example, by thermal reaction of hydrogen chloride with oxygen using catalysts or by non-thermal activated reaction of hydrogen chloride with oxygen, in which the gas mixture formed in the reaction, comprising the target products chlorine and water, unreacted hydrogen chloride and oxygen, and possibly other secondary constituents, such as carbon dioxide and nitrogen, (a) is cooled to condense hydrochloric acid as an aqueous solution of hydrogen chloride and (b) the aqueous solution of hydrogen chloride formed is separated from the gas mixture, characterised in that (c) the separated aqueous solution of hydrogen chloride is fed at least partially to an electrochemical oxidation in which at least part of the hydrogen chloride is oxidised to chlorine, (d) the chlorine gas occurring in step d) is optionally added to the gas mixture occurring in step c), (e) the residues of water present in the gas mixture from steps c) and e), in particular by

Abstract: Processes are disclosed which include: (a) providing a gas comprising chlorine, oxygen, and carbon dioxide; (b) feeding the gas to a distillation column having a head, a bottom, a rectifying section and a stripping section, wherein the gas is fed to the distillation column at an introduction point between the rectifying section and the stripping section; (c) distilling the gas in the column at a pressure of 8 to 30 bar and at a column head temperature of ?10° C. to ?60° C., to form liquid chlorine and a head mixture comprising carbon dioxide and oxygen; (d) removing the liquid chlorine from the distillation column at the bottom of the column; and (e) removing a first portion of the head mixture from the head of the distillation column, and refluxing a second portion of the head mixture in the column.

Abstract: The present invention relates to a process for absorbing chlorine from a gas containing chlorine and carbon dioxide, in particular to a process for washing small amounts of chlorine out of a waste gas stream containing a large excess of carbon dioxide, wherein the washed waste gas can be released directly into the atmosphere.

Abstract: A process for the coupled production of chlorine and isocyanates in which the sulfuric acid used for both processes is combined after use, concentrated together and returned to one or both processes.

Abstract: An isocyanate is produced by: (a) reacting chlorine with carbon monoxide to form phosgene, (b) reacting the phosgene with an organic amine to form an isocyanate and hydrogen chloride, (c) separating the isocyanate and hydrogen chloride, (d) optionally, purifying the hydrogen chloride, (e) preparing an aqueous solution of the hydrogen chloride, (f) optionally, purifying the aqueous solution of hydrogen chloride, (g) subjecting the aqueous hydrogen chloride solution to electrochemical oxidation to form chlorine, and (h) returning at least a portion of the chlorine produced in (g) to (a).

Abstract: Polyisocyanates of the diphenylmethane series are produced by a) reacting aniline and formaldehyde in the presence of an acidic catalyst to produce a polyamine, b) neutralizing the reaction mixture from step a) with a base at a temperature of more than 110° C. or neutralizing the reaction mixture from step a) with a base and heating the neutralized mixture to a temperature of more than 110° C., and c) phosgenating the polyamine from step b) to convert it to the corresponding polyisocyanate.

Abstract: The invention relates to a process for the preparation of polyamines of the diphenylmethane series, comprising

Abstract: Polyisocyanates of the diphenyl methane series having reduced color values are obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to form a polyamine, b) neutralizing the reaction mixture containing polyamine with a base, c) separating the neutralized mixture into the aqueous and the organic phases, d) adding a base to the organic phase and then e) phosgenating the resulting polyamine to produce the corresponding polyisocyanate.

Abstract: Polyisocyanates of the diphenyl methane series having reduced color values are obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to form a polyamine, b) neutralizing the reaction mixture containing polyamine with a base, c) separating the neutralized mixture into the aqueous and the organic phases, d) adding a base to the organic phase and then e) phosgenating the resulting polyamine to produce the corresponding polyisocyanate.

Abstract: Polyisocyanates of the diphenylmethane series are produced by a) reacting aniline and formaldehyde in the presence of an acidic catalyst to produce a polyamine, b) neutralizing the reaction mixture from step a) with a base at a temperature of more than 110° C. or neutralizing the reaction mixture from step a) with a base and heating the neutralized mixture to a temperature of more than 110° C., and c) phosgenating the polyamine from step b) to convert it to the corresponding polyisocyanate.