1907. -----. [KÖLBEL, H., AND ACKERMANN, P.] (Steinkohlen-Bergwerk "Rheinpreussen"). [Synthesis Catalyst.] German Patent 755,822, no date. Kainer, p. 66.

NH₃ can be used with advantage as the precipitant in making catalysts. Wholly Na-free catalysts with long life are obtained, and the consumption of distilled H₂O for washing is greatly reduced.