1420. HILPERT, S., AND DIECKMANN, T. [Iron Carbides and Their Catalytic Action on the Decomposition of Carbon Monoxide.] Ber. deut. chem. gesell., vol. 48, 1915, pp. 1281-1286; Chem. Abs., vol. 9, 1915, p. 2847.

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Literature Abstracts

1420. HILPERT, S., AND DIECKMANN, T. [Iron Carbides and Their Catalytic Action on the Decomposition of Carbon Monoxide.] Ber. Deut. Chem. Gesell., vol. 48, 1915, pp. 1281-1286; Chem. Abs., vol. 9, 1915, p. 2847.

According to Boudouard, the oxides of Fe, Co, and Ni are the principal factors in the decomposition of CO; according to Schenk and Zimmermann, the free metals, not the oxides, act as catalysts. In their experiments Hilpert and Dieckmann confine themselves to a study of the catalyst. In every case pure Fe₂O₃, which had been heated previously, was used. The CO was carefully purified and dried. At 950° the tendency of CO to separate C is very slight. In spite of this, it is surprising that at this temperature the oxide is reduced to pure Fe. After 10 hr. at this temperature a grayish metallic product was obtained, which analyzed 99.8% Fe. At 850° the formation of carbide occurs rapidly, and at the same time the separation of C occurs. Below 800° the separation of C occurs very rapidly. The evident conclusion is that not the Fe itself but a carbide hastens the reaction. The material showed no trace of magnetic properties at 200°. Since pure Fe loses its magnetic property at 750° and the carbide at 200°, only the carbide could have acted as catalyst. The mechanism of the process probably is that the apparently stable carbide Fe₃C is broken down by the action of CO into a series of compounds rich in C, such as Fe₂C and FeC. These are very unstable and tend to form Fe₃C again, with separation of C.

HINSHELWOOD, C. N. See abs. 2746, 3263, 3407.