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Carbonylation of propane in HF-SbF5 (5 : 1 molar ratio) superacid in the presence of carbon tetrachloride (or chloroform) at -30 "C yields exclusively the isobutyryl ion (isopropyloxocarbenium ion), analysis of the gaseous fluorocarbons generated as side products showing both hydride abstraction by CCI3+ (or CHC12+) and CI/F exchange on the tri-and di-chloromethane formed; in the absence of CCI4 (or CHC13) no reaction takes place under the same experimental conditions.

1999 magnetic resonance, nuclear quadrupole resonance magnetic resonance, nuclear quadrupole resonance (solids and liquids) D 6560 -016Fluoroanions and Cations in the HF-SbF 5 Superacid System. A 19 F and 1 H NMR Study.-The ionic composition of the HF-SbF 5 superacid system is reinvestigated over the whole composition range by high field 1 H and 19 F NMR. In comparison to other superacids, the ionization of HF requires larger amounts of Lewis acid. At SbF 5 concentrations higher than 20 mol% in HF increasing amounts of nonassociated SbF 5 appear. This change in composition can be related to the change in reactivity of the superacid system in the activation of small alkanes. -(CULMANN, JEAN-CHRISTOPHE;