Production of isocyanates

Abstract From the Canadian patent

Process for the preparation of organic isocyanates in which a furoxan is heated in the presence of a vicinal diketo compound containing two adjacent keto carbonyl groups. When the furoxan ring is fused to an organic ring system di-isocyanates are produced. An adduct of the furoxan and the diketo compound may be isolated from the reaction mixture and used as a stable isocyanate precursor in for example, a "one-, pot" polyurethane composition. The adduct may be represented by the structure, wherein X represents an acyclic or cyclic divalent hydrocarbonyl group and Y, Z which may be the same or different are hydrocarbyl groups which are either separate or combined into one cyclic system.