| abstract |
A process is described for preparing aromatic isocyanates by contacting an aromatic carbamate of the formula R(NHCO2R')n at 150 DEG -350 DEG C under reduced pressure with one or more metal or metal compound catalysts dissolved in an inert solvent. In the formula R is a divalent aromatic, R' is a monovalent aliphatic, alicyclic or aromatic with at most 8 carbon atoms and n is 1 or 2. The metal is dissolved in a concentration of at least 1/1000% by weight of the solvent. The vapors of the resulting aromatic isocyanate and alcohol or phenol are fractionally condensed under reduced pressure and the aromatic isocyanate is separately collected. |