Manufacture of organic isocyanates

1,140,145. Isocyanates. IMPERIAL CHEMICAL INDUSTRIES Ltd. 5 Oct., 1967 [21 Oct., 1966], No. 47164/66. Addition to 1,067,316. Heading C2C. Organic isocyanates are made by a process in which an organic nitro compound is reduced to a primary amine, the catalyst (if used) is separated by filtration, the water formed in the reduction is separated by distillation and the amine is then phosgenated, the entire process being effected in an inert liquid reaction medium consisting of an N,N-disubstituted carbamic ester, a number of which are specified. Products stated to be obtainable by the process include phenyl isocyanate, benzyl isocyanate, octyl isocyanate, cyclohexyl isocyanate, xylylene diisocyanates, diphenylmethane-4,41-diisocyanate, m-phenylene diisocyanate, naphthylene - 1,4 - diisocyanate and 1,3,5 - benzene triisocyanate. An example is given.