Process for the preparation of diisocyanates

摘要

Diisocyanate is prepared by reacting, in the gas phase, phosgene with cycloaliphatic diamine containing two 1,2- or 1,3- primary amine groups. In the preparation process: (i) gaseous diamine, optionally diluted with an inert gas or gaseous inert solvent, and phosgene heat separated at 200 - 600 C, are reacted at 200 - 600 C in a cylindrical reactor; (ii) an inert liquid solvent, at a temperature above the decomposition temperature of the carbamic chloride of the diamine is added continuously, followed by cooling of the mixture obtained; and (iii) the solvent is removed from the diisocyanate.