2710.     PLOTNIKOV, V. A., AND IVANOV, K. N.  [Decomposition of Methanol in Presence of the Zinc-Chrome Catalyzer.]  Jour. Chem. Ind. (U.S.S.R.), vol. 6, 1929, pp. 940-943; Chem. Abs., vol. 24, 1930, p. 3984.

        In the synthesis of MeOH from water gas, the reaction is reversible, and the most active catalyzers favor MeOH decomposition as well as its synthesis.  A study is made of the decomposing action of the catalyzer ZnO-Cr₂O₃ at ordinary atmospheric pressure on the MeOH already formed.  The molecular proportion of ZnO to Cr₂O₃ was 10:1.  The catalyzer was precipitated on Fe-free asbestos to increase its surface.  The precipitation should be effected by Na₂CO₃ from the solutions of the nitrates of the metals; when precipitating by NH₃, the catalyzer obtained is considerably less active.  After the precipitation, the carbonates are reduced by H₂.  Care must be taken to avoid excessive rise of temperature during the preparation of the catalyzer.  The proportion of pure catalyzer to asbestos was 1:1, the total weight of both being 9.5 gm. Apparatus.—The MeOH from a burette entered a V-shaped glass tube heated in an oil bath to 150° where it evaporated and its vapors passed into a decomposition apparatus where they were first heated, then filtered through the catalyzer.  The products obtained were cooled to liquefy and separate the undecomposed MeOH, the volume of which was measured in a burette, and the gases were collected in gasometers filed with acidified H₂O.  Influence of temperature and speed.—The first bubbles of decomposition gas appear at 240°-250°; with increase in temperature their quantity gradually increases and becomes particularly noticeable at 275°-280°; at 300° the decomposition is already very intensive.  It was found most convenient to pursue the investigation at 325°, the speed of passing in MeOH being 0.125 gm. per min.  At a greater rate of speed and at a higher temperature, for example, 335°-350°, a change takes place in the character of the decomposition and of the catalyzer itself, the MeOH decomposing 5 times faster than at 320°-325° while noncondensable white gases are emitted; these vapors are products of HCHO polymerization, whereas the condensed product is trioxymethylene; the catalyzer blackens and a gray ring of volatilized Zn is formed, Zn being reduced at about 340°-350°.  Under normal conditions of speed and temperature the condensate consists chiefly of MeOH, whereas the gases consist of H₂, CO, and CO₂.  Stability of catalyzer.—In agreement with the findings of Smith and Hawk (abs. 3210) and contrary to the statements of Taylor and Kistiakovskii (abs. 3336) and of P. V. Zimakov (Jour. Chem. Ind. (Russia), vol. 5, 1928, p. 1072), the CO₂ formed does not act as catalyzer poison, although it is strongly absorbed by the catalyzer.  The catalyzer is very stable and after 57 hr. of uninterrupted work shows no sign of fatigue.