PATENT

3735.  TEMKIN, M. I., AND PYZHEV, V. M.  [Catalyst for Ammonia Synthesis.].  Russian Patent 64,607, Apr. 30, 1945. Chem. Abs., vol. 40, 1946, p. 5216.

When Fe oxide catalyst used for H₃ synthesis is regenerated in a special apparatus outside the synthesis column, the catalyst becomes pyrophoric, and thereby loses its catalytic activity.  To prevent this, the catalyst after regeneration is cooled in a mixture of N₂ and H₂ and is treated, while cold, with a mixture of N₂ and H₂ containing a small quantity (for example, 0.1-0.2% by vol.) of O₂.  When the catalyst is placed in the synthesis apparatus, the passivating film wears off under the influence of N₂ and H₂ and the temperature within the apparatus.  The activity of such catalyst is fully equal to that of a catalyst regenerated within the apparatus.  The O₂ is best supplied by adding air to the N₂-H₂ mixture.