Fluorosulphuric acid

Immobilized Bronsted Acids Supported Fluorosulphuric Acid (FSOsH/SiOA and Trifluoroacetic Acid (CFsCOOH/SiOA- 1.6 mmoles of (3-aminopropyl) trimethoxysilane was dissolved in 100 mL of chloroform, and 1 g of silica gel was added. The slurry was heated under reflux for 24 h. The slurry... 

Olah has determined the pnmr and cnmr spectra of a number of protonated carbonyl compounds in fluorosulphuric acid-antimony pentafluoride-sulphur dioxide solution (Olah and White, 1968 Olah et al. 1972). The carbon-13 data are given in Tables 9 and 10. The proton data are not included in Table 9, since the anisotropy of the oxygen function obscures any interpretation. A correlation of some... 

Urea and substituted ureas have also been shown to be O-protonated in anhydrous media, with a second protonation ensuing on one of the N atoms in pure fluorosulphuric acid and in magic acid (Birchall and Gillespie, 1963 Olah and White, 1968). 

An interesting example of an amide which appears to remain N-protonated in pure fluorosulphuric acid at low temperature is acrylamide (Farona et al., 1969). In this molecule, the carbonyl group enters into conjugation [125] with both the amino-group and... 

The first protonation of uracil in trifluoroacetic acid was found by nmr spectroscopy to occur at the oxygen atom in the 4-position, giving a cation with extensive charge delocalization [139], and the second protonation in fluorosulphuric acid occurs at the oxygen in position 2, giving cation [140], in which the two charges are delocalized over the whole molecule (Wagner and von Philipsbom,... 

The protonation of phenol and anisole in pure fluorosulphuric acid occurs on the para-carbon (Birchall et al., 1964), but the introduction of methyl substituents in the para-position leads to competing ortho-caihon protonation (Hartshorn et al., 1971). So, for example, in the solutions of 5-methoxyhemimellitene, cations [226] and [227] occur in the ratio 2 5 at low temperature. Similar results... 

Ring protonation has been looked for in some other phenolic systems also. Thus a C-protonated cation is observed at low temperature when 2,4,6-trihydroxybenzoic acid is dissolved in 70% perchloric acid and pure fluorosulphuric acid (Birchall et al., 1964). A... 

Oxidation of alkanes involves the removal of an electron from either a carbon-hydrogen or a carbon-carbon o-bond. These are dissociative processes where the radical-cation cannot be detected as an intermediate in either fluorosulphuric acid or acetonitrile. 

Alkanes are functionalised by anodic oxidation in acetonitrile, methanol, acetic acid and more acidic solvents such as trifluoracetic acid and fluorosulphuric acid. Reaction requires very positive electrode potentials (see Table 2.1) and platinum has generally been used as anode materials in laboratory scale experiments. On a larger scale carbon is used as anode material. The first stage in these reactions in-... 

As the concentration of the very weakly basic H2S04 decreases to a very low value and the concentration of S08F decreases accordingly, so the concentration of the highly acidic H2S08F+ ion increases rapidly up to the value that it has in 100% HSO3F. Some of the properties of fluorosulphuric acid are summarized in Table 6. Fluorosulphuric acid has a boiling point of 163-7°C and it is therefore easily removed by distillation from a reaction mixture it is also readily purified by distil-... 

Selenium can be oxidized even by 100% H2S04 to a dark green solution and by oleum, to an orange solution which have been shown to contain the Se + and Se + cations respectively. These sulphur and selenium cations can also be prepared in other very weakly basic media. For example, solutions of these cations in fluorosulphuric acid can be conveniently obtained by oxidizing the element with S2OaF2. 

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