| 摘要 |
1,247,451. Isocyanates. AMERICAN CYANAMID CO. 5 Aug., 1969 [6 Sept., 1968], No. 39231/69. Heading C2C. Organic isocyanates are obtained by heating urethanes of the formula R(NHCOOR<SP>1</SP>) x ; wherein R is an optionally substituted saturated aliphatic or cycloaliphatic radical containing up to 18 carbon atoms, an aryl or aralkyl radical or an alkaryl radical containing less than three rings, R<SP>1</SP> is an optionally substituted saturated aliphatic or cycloaliphatic radical containing up to 6 carbon atoms, an aryl radical or an alkaryl radical containing less than three rings, and x is 1, 2 or 3, each R<SP>1</SP> being the same or different when x is 2 or 3; at 400‹ to 600‹ C. in the presence of a Lewis acid, the vapour produced being condensed to recover the isocyanate product. When x is 2 or 3 isocyanates containing unreacted urethane groups may be present in the reaction products. |
