Process for the production of diisocyanates

A process for the production of a diisocyanate comprising

• a) heating a vaporous diamine selected from
• 1) aliphatic diamines having two primary amino groups in the 1,2- or 1,3-positions to one another and
• 2) cycloaliphatic diamines having two primary amino groups in the 1,2- or 1,3-positions to one another to a temperature of from about 200.degree. to about 600.degree. C.,
• b) heating phosgene to a temperature of from about 200.degree. to about 600.degree. C.,
• c) introducing the diamine from step a) and the phosgene from step b) into a cylindrical reaction chamber heated to a temperature of from about 200.degree. to about 600.degree. C., which reaction chamber has no moving pads, in a manner such that a turbulent flow is maintained in the reaction chamber and the diamine from step a) and phosgene from step b) are reacted,
• d) cooling any gas leaving the reaction chamber by means of an inert liquid solvent that is maintained at a temperature above the decomposition temperature of carbamic acid chloride corresponding to the diamine used in step a),
• e) recovering a solution of diisocyanate plus inert liquid solvent, and
• f) distilling the solution recovered in step e) to isolate the product diisocyanate.