| 摘要 |
PROBLEM TO BE SOLVED: To provide a multi-process method for continuously producing an alicyclic diisocyanate in a state free from phosgene. SOLUTION: This multi-process method for continuously producing the alicyclic diisocyanate is characterized by performing the formation of a diurethane in two processes, thermally decomposing the diurethane free from low boiling point substances and middle boiling point substances under the release of the desired diisocyanate, continuously discharging a part of the decomposed bottom products of a decomposing apparatus, reurethanizing the discharged products with an alcohol, separating high boiling point substances from the product, and then returning the purified reurethanized substance to the process. According to the present invention, the stationary concentrations of the high boiling point components are low, and the deposits of the high boiling point components can be avoided. And good installation utility and a good process yield are guaranteed over a long period. On the reurethanization and the separation of the high boiling point substances after the thermal decomposition reaction, the amount of the diurethane to be converted into a gas phase is remarkably more reduced than by a conventional method for separating the high boiling point substances before the thermal decomposition reaction. Thereby, investigation cost and energy costs can be saved. COPYRIGHT: (C)2006,JPO&NCIPI
|
