Tetramethylethylene, as a model of low molecular olefin, was oxidized by molecular oxygen in chlorobenzene with cobalt-naphthenate as a catalyst at 60 ℃. Main products was found to be 2, 3,-dimethyl-2, 3,-epoxy-butane, 2, 3-dimethyl-3-hydroxy-butene-1 and 2, 3-dimethyl-3-hydroperoxy-butene-1 by IR, NMR, Mass spectrometers, and gas chromatography. It was also confirmed that hydroperoxide and epoxide were primary products and that alcohols, ketones and glycol were secondary products in the oxidation of olefinic hydrocarbon, while hydroperoxide is the sole primary product in the oxidation of paraffinic hydrocarbon. The selectivity of the catalyst for yielding epoxide increases inversely with the concentration of cobalt-naphthenate up to 45 % and the catalyst selectivity for yielding hydroperoxide depends strongly on the concentration of the catalyst.