GB946026A - Process for imparting increased activity to inorganic solid contact material - Google Patents

Abstract

Increased activity is imparted to an adsorptive refractory inorganic oxide by contacting the inorganic oxide, while in a hydrous state, at a temperature in excess of 100 DEG C. with sulphur trioxide in a non-reducing atmosphere. The refractive inorganic oxide can be alumina, silica, magnesia, thoria, zirconia, titania, boria or mixtures of two or more of these oxides; they may be naturally occurring earth, clays, sands and/or minerals, or they may be synthetically prepared. The invention is particularly applicable to alumina, silica and mixtures of the two. In a specific embodiment an adsorptive refractory inorganic oxide material which has not been heated to any temperature above 150 DEG C., is contacted with sulphur trioxide between 100 DEG and 500 DEG C. in a non-reducing atmosphere and the oxide is then calcined at a temperature of at least 500 DEG C. To ensure the non-reducing atmosphere the adsorptive refractory inorganic oxide may be purged, prior to the sulphur trioxide treatment, with any suitable gaseous material which reacts neither with the refractory oxide nor with the sulphur trioxide, e.g. air, nitrogen, argon and other inert gases may be used. In the example, wet calcined alumina spheres prepared by the oil drop method are washed with methyl alcohol and water to remove any contaminants and allowed to dry in air at room temperature. A portion of the dried spheres are treated with a sulphur trioxide gas mixture formed by the oxidation of sulphur dioxide with air over a platinum catalyst, the temperature being gradually increased from 150 to 500 DEG C. The treated alumina had a surface area of 325 sq. metres/gm.-a 62% increase over untreated alumina.ALSO:A solid contact material consisting at least predominantly of an adsorptive refractory inorganic oxide which has been activated by contacting the inorganic oxide component while in a hydrous state, at a temperature greater than 100 DEG C. with sulphur trioxide in a non-reducing atmosphere (see Division C1), is used as a carrier for a catalytically active metal component. The adsorptive refractory inorganic oxide is first activated as above and then impregnated with a minor proportion of a catalytically active metal component; metal components mentioned are platinum, iridium, palladium, ruthenium, rhodium, osmium, iron, cobalt, nickel, chromium, molybdenum, and tungsten. The amount of metal component used is generally such that the final catalyst composite contains 0,01-20% by weight of the metal component. The carrier material which may for example be alumina, silica, magnesia, thoria, zirconia, titania, boria or mixtures thereof, or a naturally occuring earth, clay, sand, and/or minerals (or a synthetically prepared material), may be impregnated with a halogen and used in the reforming of hydrocarbons.