| 摘要 |
Highly porous catalysts are prepared by mixing catalytic material with sufficient water to form an extrudable moist mass which upon normal extrusion forms pell extruding the mass under conditions to dry rapidly the surface of the extrudate, cutting into pellets of suitable length, and drying thoroughly. The moist mass may be extruded through a perforated die-plate, and the surface dried by exposure to a stream of gas, e.g., air, nitrogen, flue or exhaust gas, at a temperature of 80-120 DEG C. for 1/20 to 5 seconds. After drying, e.g., at 150-300 DEG C., the material may be activated by calcination. The catalytic material may comprise oxides or salts of the heavy metals or of other elements, and may be mixed with carriers. Stearic acid, hydrogenated cottonseed oil, tannic acid, or Quebracho extract added to the moist mass aid in extrusion. The addition of strengthening materials, e.g., ferric sulphate and potassium hydroxide to iron oxide, is also referred to. The water content of the moist mass in the case of iron-group catalysts may be from 20-60 per cent., preferably 25-30 per cent. In an example a catalyst suitable for the dehydrogenation of butylens to butadiene is prepared from a mass containing iron oxide, chromium oxide, potassium carbonate, and tannic acid. The catalysts may be used in other hydrocarbon conversion processes, e.g., the formation of styrene from ethyl benzene, and in other types of catalytic reaction.ALSO:A highly porous catalyst suitable for the dehydrogenation of butylene to butadiene is prepared by extruding under conditions to dry rapidly the surface of the extrudate (see Group III) a moist mass containing iron oxide, chromium oxide, potassium carbonate as a strengthening agent, and tannic acid as an extrusion aid.
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