Aromatic isocyanate synthesis - by making N-aryl mono:urethane, condensing to di:urethane and decomposing by heating

摘要

Isocyanates of formula (I) are made without using phosgene as raw material, by (a) making an N-aromatic mono-urethane of formula (II), in which R is (m)ethyl, or aryl; (b) condensing this to a diurethane of formula (III); and (c) thermal decomposition to obtain (I). .