Patent ID: 6992214
Filing Date: 2006-01-31
Classification: C07C,Y02P

Abstract:
1. An integrated process for the preparation of aromatic isocyanates comprising: (a) a reaction between an aromatic amine and an organic carbonate, optionally in the presence of a solvent that is inert with respect to reagents under operating conditions, in the presence of a catalyst selected from organic and inorganic salts of a metal selected from Zn, Sn, Pb, Cu to form an aromatic urethane and an alcohol; (b) removal of the catalyst; (c) passivation of the residual quantities of metal in the aromatic urethane formed in step (a); (d) removal of the solvent and optionally recycling it to step (a) of the reaction; (e) evaporation of the aromatic urethane with partial pyrolysis; (f) complete pyrolysis of the urethane in gas phase to form an aromatic isocyanate; and (g) recovery of the aromatic isocyanate.