497. DIRECTIE VAN DE STAATSMIJNEN IN LIMBURG. [Conversion of Carbon Monoxide With Iron Oxide Catalysts.] Netherlands Patent 70,261, June 16, 1952. Chem. Abs., vol. 47, 1953, p. 296.

Patent Abstracts

Suitable catalyst for the conversion of CO with steam is ¡-Fe₂O₃ or a lower oxide obtained by the reduction of this oxide. The catalyst may be prepared by precipitated Fe₃O₄ from an equimolecular mixture of a ferrous and a ferric salt: this precipitate is converted to ¡-Fe₂O₃ by O from the air. Preferably the precipitate is heated gradually not > 330°. A solution of a Cr salt, chromic acid, a chromate, or a bichromate may be added before heating; the catalyst then contains Cr₂O₃. If a-Fe₂O₃ is used as the starting material, this at 1^st must be heated in a reducing atmosphere to form Fe₃O₄. If a ferrous salt is used, this is partly converted to the ferric form with the aid of K₂Cr₂O₇. In an example, a solution containing 20% of equimolecular quantities of ferrous and ferric salts is added to a strong solution of NaHCO₃while stirring until pH is 7.5. After precipitation the clear liquid is removed by suction, the precipitate is washed, filtered, and dried at 110°: by this method Fe₃O₄ is converted to ¡-Fe₂O₃. Then Cr nitrate is added so that the resulting product contains 8% Cr. The mixture is kneaded, dried, and made into tablets, which are roasted at 350°-375° for 3 hr. while air is passed through them. Over this catalyst a mixture of 1 part of CO and 5 parts of steam is passed at 350° and normal pressure. If the velocity of the gas is 1,200 normal cc. per hr. per cc. catalyst, a conversion is obtained amounting to 95.4%.