On the catalytic cyclization of aliphatic hydrocarbons. I

Abstract

The aromatization of a paraffin proceeds through the formation of a mono-olefine which is held on the catalyst by two-point contact. The promoter action of the central atoms in heteropoly acids of molybdenum can be attributed to the stabilization of the molybdenum dioxide produced during the hydrogen pretreatment. The alumina used as a support for molybdenum catalysts plays the same role. In the reduction of phenol to benzene by the heteropoly acids of molybdenum the metal is the catalyst. The variation of yield of the total aromatic hydrocarbon with different paraffin feeds can be calculated by assuming two point contact. A yellow compound (fulvene or a polymer of fulvene) is for given conditions produced in a constant ratio to the aromatic hydrocarbon. The loss of activity of the catalyst with use is a result of the polymerization to giant molecules of the hydrocarbons adsorbed on adjacent catalyst centres. This decay rate may be diminished by decreasing the concentration of active centres on the surface.