METHOD OF OBTAINING ISOCYANATES Russian patent published in 2015 - IPC C07C263/10 C07C265/14 

FIELD: chemistry.

SUBSTANCE: invention relates to method of obtaining isocyanates by interaction of primary amines with phosgene in stoichiometric excess in gas phase. In accordance with claimed method at stage a) amine interacts with phosgene in reactor at temperature higher than temperature of said amine boiling, with formation of isocyanate-containing liquid flow, and HCl and phosgene-containing gaseous flow. At stage b) HCl and phosgene-containing gaseous flow, obtained at stage a), first in succession from the step of absorption in isothermal mode and step of absorption in adiabatic mode is divided into HCl-containing gaseous flow and phosgene-containing liquid flow. At stage c) phosgene-containing liquid flow, obtained at stage b), is divided into phosgene-containing gaseous flow and liquid flow. At stage d) phosgene-containing gaseous flow, obtained at stage c), is returned into reaction to stage a), with e) pressure in phosgene-containing gaseous flow, obtained at stage c) being higher than pressure in liquid phosgene-containing flow, obtained at stage b).

EFFECT: method makes it possible to regenerate excess of phosgene, applied in reaction, and minimise its loss, which results in process simplification and increase of its profitability.

8 cl, 6 ex