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Alumina-doped and magnesia-doped cobaltous-cobaltic oxide, Co3O4, samples of about 8 and 9 cationic percent dopant concentrations, respectively, were prepared and tested for catalytic activity relative to that of the pure cobalt oxide. They were also analyzed by ion scattering spectrometry (ISS), to look for possible surface enrichment of the dopant. The specific catalytic activity of the Al2O3-doped Co3O4 was found to be depressed by a factor of about 4–5, while the MgO-doped Co3O4 was poisoned by a factor of about 8. The ISS spectra clearly indicate that the alumina-doped sample has a surface which is highly enriched in aluminum concentration, relative to the bulk. The ISS results for the Mg-doped sample are difficult to interpret, but at least show that the outermost surface layers are impoverished in cobalt, hence they are probably enriched in magnesium. These experiments were designed to partially test a hypothesis of “poisoning by substrate dissolution,” to account for the fact that Al2O3-supported Co3O4 has a peculiarly low catalytic activity for the oxidation of CO and hydrocarbons compared to pure Co3O4. Similar, though somewhat less striking results are obtained for MgAl2O4-supported Co3O4. Such supported catalysts are generally made by impregnation with aqueous cobalt nitrate, followed by calcination to about 500–600 °C. There is evidence that this temperature is insufficient to produce profound bulk interdiffusion between catalyst and support in the solid state, and that there is a Co3O4 phase left. It was therefore theorized that the decomposing cobalt nitrate, a hot, acidic liquid, might dissolve some of the substrate, thus yielding substrate-doped Co3O4 similar to the doped samples described above. Our results appear to fall short of explaining the peculiarly low activity of Al2O3-supported Co3O4, but are large enough to possibly explain the performance of the MgAl2O4-supported catalyst.

Wax esters, isolated fromTetrahymena pyriformis, have been found to contain 45% branched chain alcohols and 76% branched chain fatty acids. No esters of tetrahymanol or of sterols were found.