Production of isocyanates
AssigneeImperial Chemical Industries PLC
InventorsJohn Crosby, Robert Allan Campbell Rennie, Robert Michael Paton
Life of this patent
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Abstract
A furoxan, especially one in which the furoxan ring is fused to a strained aliphatic ring system, is heated in the presence of sulphur dioxide to give an isocyanate. The process enables furoxans, such as dicyclopentadiene furoxan, which ring-open at temperatures <180.degree. C to be converted into isocyanates. In the absence of sulphur dioxide, may be difficult to control the reaction and, in some cases, no isocyanate is obtained. Diisocyanates prepared by the process may be converted into polyurethanes by reaction with suitable hydroxylic compounds.
Claims7
A process for the production of an organic isocyanate which comprises heating a furoxan in the presence of sulphur dioxide to give an isocyanate wherein the furoxan has the formula:
- ##STR18## where R and R.sup.1, which may be the same or different, are either separate aliphatic or aromatic hydrocarbon groups containing from 1 to 18 carbon atoms or, alternatively, R and R.sup.1 form part of a second ring system fused to the furoxan ring, the furoxan being one which ring opens on heating to a temperataure below 180.degree. C.
Dependencies are inferred from the claim text.