MEHRSTUFIGES VERFAHREN ZUR KONTINUIERLICHEN HERSTELLUNG VON CYCLOALIPHATISCHEN DIISOCYANATEN

摘要

Preparation of cycloaliphatic diisocyanante (a) involves reacting cycloaliphatic diamine with a carbonic acid derivative and an alcohol to produce a cycloaliphatic urethane (b); separating (b) from low, middle and high boilers; thermally cleaving (a) to produce (a); and continuously discharging a portion of the cleavage residue, reurethanizing the portion with an alcohol and recycling directly into the lower-boiler separation.