PROCEDE DE SEPARATION EN CONTINU DES RESIDUS DE DISTILLATION DES ISOCYANATES BRUTS

摘要

1336385 Isocyanates BAYER AG 15 July 1971 [18 July 1970] 33302/71 Heading C2C [Also in Division B1] The invention comprises a process for the single stage continuous removal of residues from isocyanate concentrates which are obtained when crude isocyanate solutions which have been prepared by reacting amines with phosgene are worked up by distillation, in which volatile isocyanate contained in the concentrates is evaporated under vacuum in a system comprising downpipe evaporator and vacuum vessel, the thin liquid residue discharged from the vacuum vessel is returned to the inlet of the downpipe evaporator, and part of the residue is continuously discharged from the cycle thus formed.