Preparation of organic compounds using as a reactant an adduct of isocyanic acid and a tertiary amine or an ether

A process for the preparation of asymmetrically substituted ureas, carbamates, thiocarbamates or substituted isocyanates, comprising:

• providing an adduct of isocyanic acid and a tertiary amine or an ether, prepared by a process which comprises introducing a tertiary amine or an ether into a gaseous mixture of isocyanic acid and ammonia at a temperature of 250.degree. to 600.degree. C., introducing the resulting gaseous reaction mixture into a diluent which is inert under the reaction conditions, and cooling the reaction mixture whereby an adduct of isocyanic acid and tertiary amine or ether condenses, and
• reacting the adduct in an inert diluent at temperatures of -20.degree. C. up to the boiling point of the diluent, with a primary or secondary amine to give asymmetrically substituted ureas, an alcohol to give carbamates, a thiol to give thiocarbamates, or a compound which contains one or two non-cumulated olefinic double bonds to give substituted isocyanates.