Patent ID: 6838578
Filing Date: 2005-01-04
Classification: B01J,C07C

Abstract:
1. A process for preparing a (cyclo)aliphatic diisocyanate or triisocyanate corresponding to the formula wherein R represents a (cyclo)aliphatic hydrocarbon group having up to 15 carbon atoms, provided that there are at least two carbon atoms between two nitrogens, n represents the number 2 or 3, which comprises a) separately heating phosgene and a diamine or triamine corresponding to the formula  to a temperature of 200° C. to 600° C., wherein the amine may optionally be diluted with an inert gas or with the vapors of an inert solvent, b) optionally passing the reactants over torque-producing baffles and c) continuously reacting phosgene and the amine in the gas phase in a reaction chamber without moving parts and with constrictions of the wall in the region of the reaction zone, wherein the reaction chamber has an abrupt widening of the cross-sectional area in the direction of flow after the mixing of the reactants.