Verfahren zur Herstellung von Isocyanaten und kontinuierlichen Aufarbeitung des Rückstandes

摘要

The invention relates to a process for producing pure, distilled isocyanates by reacting the corresponding amines with phosgene in a suitable solvent and multistage workup by distillation to provide pure isocyanates, pure solvent and a proportion of residue, this residue being continuously worked up. The workup is characterised in that the residue obtained from the distillation process, together with 2-50% by weight of high-boiling hydrocarbons, preferably bitumen, which are inert under the distillation conditions, is continuously fed to a heated product-agitating vacuum drier having a horizontal shaft, the proportion of isocyanates still present in the residue is continuously distilled off at temperatures of 160 to 280@C under pressures of 2 to 50 mbar and the remaining residue is continuously discharged as flowable non-dust forming granules, cooled if necessary and, if necessary after grinding, incinerated.