The present invention relates to a process for the preparation of aliphatic, cycloaliphatic, araliphatic and aromatic mono- and oligoisocyanates by phosgenation of the corresponding primary amines at atmospheric pressure, which comprises a) introducing a catalytic amount of a monoisocyanate (isocyanate a) into an inert solvent together with phosgene; b) adding the primary amine, and c) reacting the resulting reaction mixture with phosgene.

A invenção atual relaciona-se a um processo para a preparação de mono- aliphatic, cycloaliphatic, araliphatic e aromatic e de oligoisocyanates pelo phosgenation dos amines preliminares correspondentes na pressão atmosférica, que compreende a) introduzindo uma quantidade catalytic de um monoisocyanate (isocyanate a) em um solvente inerte junto com o phosgene; b) adicionando o amine preliminar, e c) reagindo a mistura de reação resultante com o phosgene.