| abstract |
The invention relates to a multi-stage process for the continuous phosgene-free production of (cyclo) aliphatic diisocyanates, which converts (cyclo) aliphatic diamines in a distillation reactor into the corresponding (cyclo) alkylene bisureas, their reaction with alcohol in a pressure distillation reactor to give the (cyclo) alkylene bis carbamates and the thermal cleavage of the latter in a combined cleavage and rectification column into the (cyclo) alkylene diisocyanates and alcohol in the liquid phase without the use of solvents. |