| 摘要 |
N-Alicyclic carbamates, useful in making polyurethanes, are prepared by nuclear hydrogenation of an N-aryl carbamate using a group VIII transition metal catalyst. E.g., dimethyl 4,4'-methylenedicarbanilate is contacted with hydrogen and ruthenium catalyst in 2-propanol medium, at 50 DEG C. for 1.3 hours under a pressure of 500-800 psi, to form dimethyl 4,4'-methylenedicyclohexylcarbamate. Acid activation of catalyst is a feature of the invention. |
