Continuous and multistep process for the preparation of (cyclo)-aliphatic diisocyanates

摘要

The invention relates to a multistep process for the continuous phosgene-free preparation of (cyclo)aliphatic diisocyanates, which comprises the conversion of (cyclo)aliphatic diamines in a distillation reactor into the corresponding (cyclo)alkylene-bis-ureas, the conversion thereof with alcohol in a pressure distillation reactor into (cyclo)alkylene biscarbamates and the thermal cracking of the latter in a combined cracking and rectifying column into the (cyclo)alkylene diisocyanates and alcohol in the liquid phase without the use of solvents.