Preparing High-Octane Motor Fuel Components via the Oxidation of an Industrial Isobutane Fraction

Abstract

The deep processing of heavy oil increases the production of hydrocarbon gases. The resulting butanes do not always find an equivalent market. A mixture of oxygenates with a high octane number is obtained in this work via oxidation of industrial isobutane fraction. The reaction proceeds both in with and without using Au/Silicalite-1 and Cu/SiO₂ as catalysts. The influence of factors that reduce the formation of undesirable impurities (hydroperoxides, peroxides, and acids) is studied. Tert-butyl alcohol (TBA) obtainable with a selectivity of 64–69% and butane conversion of 55–69% is a target product. TBA has a RON of 113. Alcohols and ketones having RONs within 106–115 appear together with TBA during the oxidation. The best result was obtained for a Cu/SiO₂ catalyst. More than 18% of TBA and 2.9 times more ketones are removed from a unit volume of a reaction space in the presence of a catalyst than during oxidation without a catalyst. The total productivity of the products suitable as high-octane components is 40 g/(L h), while the RON of this mixture is ≈111. A mixture of oxygenates including TBA has a lower volatility than that of methyl tert-butyl ether, which is especially important for the stability of gasolines in summer.