Homogenizing Metal Oxide Catalysts

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Abstract
Metal oxide particles have been prepared which are “soluble” in hydrocarbon solvents. The reaction of either a metal (or its metal oxide) with water, mineral spirits, and a mixture of carboxylic acids can result in hydrocarbon-miscible metal oxide core particles of 20-1000Å diameter sizes which are coated with a layer of hydrophobic carboxylates. This will only occur if the metal:acid ratio exceeds one. The particle size increases as the metaltacid ratio increases. The surface carboxylate groups are in equilibrium, preventing the use of colligative property measurements in determining molecular weights. Sedimentation velocity studies confirmed that particle aggregation equilibria occur which are solvent dependent. Aggregation is more serious in polar solvents. The distribution of carboxylic acids used did not effect the particle size. Cobalt and manganese oxide particles have been used in oxidations of cyclohexane, toluene, and xylenes. Cobalt oxides were used in hydroformylations of 1-pentene, Nickel oxide catalysts were tested in hydrogenations of 1-pentene, polybutadiene, polyisoprene, and aromatic compounds. The nickel oxides were much more active upon addition of Et3Al. Cobalt oxide systems were active in the syndiotactic 1,2-polymerization of butadiene. The oxide particles could be coated onto supports such as silica, alumina, and kieselguhr followed by oxidation to give supported metal oxides. deduction with hydrogen or metal hydrides or Et3Al gave supported metal catalysts. The activity of these supported catalysts were investigated.

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