| 摘要 |
Preparation of unsaturated fatty alcohols by the continuous hydrogenation of unsaturated fatty acids with 8 to 22 carbon atoms, or their esters with monohydric aliphatic alcohols, at elevated temperatures and pressure, with a large excess of hydrogen, in the presence of zinc-chromium or zinc-aluminium catalysts in tablet form, which have been subjected to a high-temperature treatment at 400-1000 DEG C. in a reducing atmosphere. The starting materials may be mono- or poly-unsaturated fatty acids occurring in natural fats or specified esters thereof particularly the readily volatile esters with C1- 4 monohydric alcohols such as methanol. The catalysts are obtained by mixing zinc oxide with aqueous chromic acid or with an aqueous suspension of chromic hydroxide, g -aluminium oxide or amorphous or crystalline aluminium hydroxides (the hydroxides preferably being freshly prepared); drying the slurry; forming the dried mixture into tablets; optionally roasting in air or oxygen when chromates are present in the mixture and, finally, heating at normal pressure for 1 to 10 hours at 400 DEG to 1000 DEG C. in hydrogen and/or carbon monoxide (e.g. derived in situ from methanol vapour). The unsaturated fatty acids or their esters are hydrogenated, optionally in the presence of monohydric alcohols having 1 to 4 carbon atoms such as methanol, substantially in the vapour phase at 250 DEG to 330 DEG C., 100 to 500 atmospheres and with 10 to 100 Nm3 of hydrogen per litre of material to be hydrogenated. The hydrogenation of oleic acid, methyl and iso-propyl oleate, soya bean fatty acid methyl ester and sperm oil to give the corresponding alcohols is described and the dependence of the activity of the catalyst on the mode of pretreatment is demonstrated by comparative examples.ALSO:Zinc-chromium or zinc-aluminium catalysts, preferably in tablet form, which have been subjected to high temperature treatment in a reducing atmosphere are obtained by mixing zinc oxide with aqueous suspensions of chromic oxide or hydroxide, g -aluminium oxide or amorphous or crystalline aluminium hydroxides (the hydroxides preferably being freshly prepared), drying the slurry, forming the dried mixture into tablets, optionally roasting in air or oxygen when chromates are present in the mixture, and then heating at normal pressure for 1 to 10 hr. at 400 DEG to 1000 DEG C. in hydrogen and/or carbon monoxide (e.g. derived in situ from methanol vapour). The preparation of catalysts from zinc oxide (8.1 Kg.) and chromium (VI) oxide (5 Kg.) or chromic hydroxide obtained by reducing chromium (VI) oxide (5 Kg.) with methanol, zinc oxide (1 Kg.) and amorphous or crystalline aluminium hydroxide (1 Kg.), g -aluminium oxide, aluminium hydroxide precipitated from Al2(SO4)3.18H2O (4.26 Kg.), or chromium (VI) oxide obtained by treating chromic sulphate (2.2 Kg.) with ammonium hydroxide. |
