| 摘要 |
<p>1281442 Fluorination catalyst DYNAMIT NOBEL AG 27 Feb 1970 [1 March 1969] 9732/70 Heading B1E [Also in Division C2] A catalyst is obtained by the hydrofluorination of gamma- and/or eta-alumina impregnated with one or more chromium salts and consists of 1 to 15% wt chromium, 6 to 18% wt oxygen, 42 to 39% wt fluorine and the remainder aluminium. The catalyst is formed by heating alumina in a vacuum of less than 1 mm Hg at 50 to 120‹C, impregnating with a solution of chromium salt(s), drying and then hydrofluorinating, suitable by heating in a mixture of air and hydrogen fluoride, the concentration of HF being continuously increased until pure hydrogen fluoride and the heating being continued until the exothermic reaction abates. Preferably the temperature should not exceed 250‹C in the latter step. Chromium salts specified are the chromic chloride, sulphate, nitrate, ammonium or potassium chromates and potassium dichromate. The catalyst may be regenerated by passing air over at a temperature of 200 to 300‹C.</p> |
