I
K. C. STEIN, J. J. FEENAN, G. P. THOMPSON, J. F. SHULTZ, L. J. E. HOFER, and R. B. ANDERSON Bureau of Mines,
U. S. Department of the Interior, Pittsburgh, Pa.
A n Approuch to Air Pollution Control
Catalytic Oxidation of Hydrocarbons Catalysts based on oxides of cobalt, nickel, manganese, chromium, and iron appear to be good possibilities for the auto smog catalytic muffler
T,Ehydrocarbons
in the exhaust gases from automobile engines are a major source of the eye irritating smog occurring in urban areas. Catalytic oxidation applied where the pollutants o r i g i n a t e t h e individual vehicle-is one of the more logical methods of control. I n a search for suitable catalyst components, a large number of metal oxides in granular form, unpromoted and unsupported, have been investigated by a new microcatalytic technique based on gas chromatography. This technique has proved to be a convenient means for rapid screening in oxidation studies. I t is recommended when many catalysts or reactants are to be investigated or when a wide range of temperatures is to be used. The most active of the catalysts were, arranged in order of decreasing effectiveness, the oxides of cobalt, nickel, manganese, chromium, and iron. It is probable that different forms or preparations of the same oxide would have different activities. I n general, the higher molecular weight hydrocarbons were more easily oxidized than the lower. Hydrocarbons of a given carbon number increased in reactivity according to the series : branched paraffin normal aromatic alicyclic paraffin < olefinic < acetylenic. Fortunately, the olefinic hydrocarbons generally considered the most undesirable are relatively easy to remove.
