Hydroxyl cation, incipient

H202 in superacids at —78°C converts simple straight-chain alkanes into primary alcohol (ethane), or secondary alcohols and ketones (propane, butane).1,62 89 9° Electrophilic hydroxylation of the secondary C—H bond by the incipient hydroxyl cation formed through the protolytic cleavage of hydroperoxo-nium ion accommodates these observations ... 

Oxenium Ions. Oxenium ions similar to nitronium ions are, in general, too reactive to be observed. The parent ion—that is, the hydroxyl cation HO+—is elusive, and it is improbable that it can be observed in its free form in the condensed state. However, the incipient hydroxyl cation is involved in acid-catalyzed electrophilic hydroxylation with protonated (or Lewis acid complexed) hydrogen peroxide (HO—OH2+) or ozone (HO—O—0+).125 Nitrous oxide is also apotential precursor for the hydroxyl cation (in its protonated form). The hydroxy diazonium ion HON2+ has not yet been observed. 

The reactive methoxy species formed from methanol and dimethylether may be regarded as an incipient methyl carbenium ion in the same way that the acidic hydroxyl group from which it is formed is an incipient proton, or as a methyl oxonium cation... 

For example, five types of hydroxyl groups are predicted to occur on the (100), (111), and (110) surfaces of aluminas, as depicted in Figure 1. The relative concentration and distribution of these groups depends on the exposed faces. Dehydroxylation of the surface, according to equation (1), yields surface oxo groups and exposes aluminum cations. The surface hydroxyl groups have Bronsted acidity, while exposed metal cations behave as Lewis acids. Alumina surfaces with Lewis acidity can be prepared from aluminum alkoxides under mild conditions by protecting the incipient Lewis acid site with... 

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