METHOD OF EXTRACTION OF PHOSGENE Russian patent published in 2019 - IPC B01D53/22 C07C263/10 

FIELD: chemical industry.

SUBSTANCE: invention relates to a method for extracting a compound of a phosgene series from a gas source stream, comprising: providing a membrane contactor module, containing a membrane that has at least two sides: gas side and liquid side; ensuring the flow of the source gas stream, containing a compound of the phosgene series on the gas side of the membrane; and allowing the flow of a liquid extractant suitable for dissolving a compound of the phosgene series, on the liquid side of the membrane contactor module, so that the stream of liquid extractant absorbs the compound of the phosgene series from the source gas stream and provides a second stream of liquid extractant, enriched with the compound of the phosgene series, the source gas stream containing the compound of the phosgene series and the second gaseous compound selected from the group consisting of hydrogen chloride, carbon monoxide, carbon dioxide, nitrogen and/or chlorine, as well as any combination thereof; in which the flow of the liquid extractant has a higher dissolving ability with respect to the compound of the phosgene series, than with respect to the second gaseous compound; and in which the second gas stream depleted in the phosgene series is provided. Invention also relates to a method of converting an amine to the corresponding isocyanate component by phosgenating an amine, the method includes the steps of: feeding the reaction mixture containing amine and phosgene to the phosgenation reactor; at least partially converting the amine and phosgene present in the reaction mixture to the corresponding isocyanate component and hydrogen chloride, thus ensuring a liquid isocyanate stream, containing isocyanate component, phosgene and hydrogen chloride; removing at least part of the phosgene and at least part of the hydrogen chloride from the liquid isocyanate stream as a remote gas stream; optionally, partial condensation of the remote gas stream with the provision of a liquid intermediate mixture and a gas stream coming from the stage of partial condensation; optionally, distillation and/or distillation and/or washing with a solvent a stream of gas coming from the partial condensation step and/or a liquid intermediate mixture to provide a gaseous mixture containing hydrogen chloride and phosgene; providing a source gas stream containing phosgene and hydrogen chloride, which is a remote gas stream, or which is a gas stream coming from the partial condensation stage, or which is an exit gaseous mixture or a combination thereof; extraction of phosgene from the source gas stream according to any one of paragraphs 2–10, in which the second gaseous compound is HCl, with the provision of phosgene-poor second gas stream and phosgene-enriched extractant.

EFFECT: providing a phosgene-depleted second gas stream and phosgene-rich extractant.

17 cl, 5 dwg, 5 tbl