METHOD OF PRODUCING XYLYLENE DIISOCYANATES (XDI) Russian patent published in 2021 - IPC C07C263/10 C07C263/20 C07C265/14 

FIELD: chemical or physical processes.

SUBSTANCE: invention relates to a method of producing xylylene diisocyanates XDI, particularly meta-xylylene diisocyanate mXDI. Method includes steps a)–c). Step a) involves phosgenation of xylylenediamine XDA, particularly m-xylylenediamine mXDA in the case of mXDI. At step b) hydrochloric acid is removed from the reaction medium obtained at step a) at temperature of 120 to 190 °C, and at pressure of 1 mbar to 20 bar. At step c) purification of XDI involves, for example, a step for removing COCl₂; a step for removing a solvent from the phosgenation reaction; a step for removing heavy compounds formed during the phosgenation reaction; and a step for removing light compounds formed during the phosgenation reaction. Reaction at step b) is maintained until analysis of the obtained reaction medium shows content in the reaction medium of allophanoyl chloride XDI, preferably mXDI, less than 3 wt %, preferably less than 2 wt %, preferably less than 1 wt %, excluding amount of solvent, phosgene and HCl.

EFFECT: disclosed method enables to minimize the presence of undesirable intermediate chemicals and increase the yield of the diisocyanate compound.

13 cl, 4 dwg, 5 ex