INTEGRIERTES VERFAHREN ZUR HERSTELLUNG VON AROMATISCHEN ISOCYANATEN UND VERFAHREN ZUR HERSTELLUNG DER ZWISCHENPHASEN

摘要

Integrated process for the preparation of aromatic isocyanates comprising: the reaction between an aromatic amine and an organiccarbonate in the presence of a catalyst selected from organic and inorganic salts of a metal selected from Zn, Sn, Pb, Cu; the removal of the catalyst; the passivation of the quantity of residual metal in the urethane formed in step a); the removal of the organic solvent and its optional recycling to step a) of the reaction; the evaporation of the aromatic urethane with partial pyrolysis; the complete pyrolysis of the urethane in gas phase; the recovery of the isocyanate.