13-04-2017 дата публикации
Номер: US20170101367A1
This invention relates to a process for operating a gas phase phosgenation plant () to form an isocyanate () by reacting an amine () with phosgene (), in which the gas phase phosgenation plant is started up by first charging the plant with phosgene. At the same time as, or after the first charge of phosgene, the amine supply devices are rendered inert using a hot inert gas stream (). Then, amine is admixed for the first time. In this way and by maintaining a pressure drop in the amine and phosgene devices to the mixing zone, the back mixing of phosgene into the amine-containing reactant stream during start-up is prevented. 1100421100. A method of operating a gas has phosgenation plant () for producing an isocyanate () comprising reacting an amine () with phosgene () , in which said gas phase phosgenation plant () comprises at least{'b': 1000', '10, '(i) an apparatus for providing a gaseous phosgene stream (),'}{'b': 2000', '20, '(ii) apparatus for providing a gaseous amine stream (),'}{'b': 3100', '10', '20', '1100', '2100', '1000', '2000, '(iii) a mixing zone () for mixing the streams () and (), with the mixing zone being connected by connecting devices (, ) to the apparatus and the apparatus ,'}{'b': 3200', '3100', '10', '20, '(iv) a reaction zone () arranged downstream of the mixing zone () for further conversion of the previously mixed streams () and (),'}{'b': 4000', '3200, '(v) a reaction stopping zone () arranged downstream of the reaction zone () to end the reaction,'}and optionally{'b': 5000', '1', '5100', '5200, '(vi) a workup section (), which comprises devices for recovery and recycling of unconverted phosgene (″) () and devices for obtaining the isocyanate prepared in pure form (),'}{'b': '100', 'wherein the gas phase phosgenation plant () is started up by{'b': 10', '1000', '10', '1100', '3100', '3200', '4000', '3100, 'sub': 10', '10', '10', '3100, '(I) providing a gaseous phosgene stream () at a temperature Tof 200° C. to 600° C. with an absolute ...
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