| 摘要 |
1,226,099. Tetrahydrobenzotriazole. GEIGY (U.K.) Ltd. 19 July, 1968 [21 July, 1967], No. 33535/67. Heading C2C. 4,5,6,7 - Tetrahydrobenzotriazole is prepared by reduction of benzotriazole or N - hydroxybenzotriazole using molecular hydrogen and a metal hydrogenation catalyst. It is preferred to effect reduction using an excess of hydrogen at 25‹-200‹ C. under superatmospheric pressure by vigorous agitation of the benzotriazole in an inert solvent in a sealed reactor. Specified metal catalysts are Rh, Ni, Pd and Pt and mixtures thereof. The metal may be supported on a conventional carrier. It is preferred to subject the benzotriazole compound to a pre-treatment to remove sulphur and other hydrogenation catalysts poisons therefrom. The pre-treatment may comprise agitation of a solution of the compound with a desulphurization or hydrogenation catalyst, e.g., Pt, Pd, Rh, Ni, Fe, Co or Zn metal. In examples a Rh/charcoal hydrogenation catalyst is used. |
