Superacids Supported on Solids

Reaction of Butane over SbFs-Treated Metal Oxides at 20°C 

The product distributions obtained over the catalysts are summarized in Table II for the reaction of butane (29, 31, 32). The activities varied with the kinds of metal oxides that were treated with SbF,. SbF,/ Si02-Ti02 showed the highest activity, and SbF,/Ti02 was highly selective for the skeletal isomerization of butane, the selectivity being 72%. On 

Conversions of several alkanes proceeded at room temperature or below, over the metal oxides treated with SbF5 the conversion rates of alkanes were in the following order cyclohexane = methylcyclopen-tane hexane pentane = 2-methylbutane butane = 2-methylpropane propane 2,2-dimethylpropane — ethane - methane (31, 32). 

A comparison of the reactivity of SbF5-treated metal oxides with that of HS03F-, SbCl5-, and HS03F-SbF5 (magic acid)-treated catalysts showed that the former was by far the best catalyst for reaction of alkanes (31, 32). Tracer studies of conversion of alkanes catalyzed by the superacids were performed it was suggested that the reactions proceeded by carbenium ion mechanisms in which the reactions were initiated by abstraction of H from the reactants (33). 

Namba and co-workers prepared SbF5/HY-zeolite catalysts and examined them in the reaction of pentane. Although the catalysts were quite active in the initial stage, they were completely deactivated afterward by the formation of heavy hydrocarbons (34). Krzywicki and co-workers also 

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Liquid-phase oxidation, 2,6-di-tert-butylphenoI on Cu " -TSM, 39 322-324 Liquid superacids, supported on solids, 37 168-171 Lithium... 

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