Fluorosulfonate ion

Fluorosulfonate ion, 2 124-125 Fluorosulfonic acid, 2 123-124, 145, see also Fluorosulfuric acid esters, 2 126-127, 145 Fluorosulfonylamide ions, 19 193-206 Fluorosulfonyl-nitrogen compounds, syntheses and properties of, 14 363-372 iV-Fluorosulfonylpentafluorosulfanylamine, 19 190, 191... 

The fluorosulfonate ion is present in aqueous solutions of fluorosulfonic acid or its salts. It hydrolyzes slowly according to the equation S03F + H20 —< S04= + F + 2H+. In a slightly alkaline solution the reaction is first order with respect to the fluorosulfonate ion with a heat of activation of 17.9 kcal and an entropy of activation of —31 cal/degree. In acidic solutions the rate is more rapid than in neutral or basic solutions 258). 

Since the fluorosulfonate ion has the same sort of structure and charge... 

In general the salts of fluorosulfonate ion are very soluble in water, the only highly insoluble one being that formed by the organic base, nitron (211). 

Arsenic trifluoride (arsenic(III) fluoride), AsF, can be prepared by reaction of arsenic trioxide with a mixture of sulfuric acid and calcium fluoride or even better with fluorosulfonic acid. Chlorine reacts with ice-cold arsenic trifluoride to produce a hygroscopic soHd compound, arsenic dichloride trifluoride [14933-43-8] ASCI2F35 consisting of AsQ. and AsF ions (21). Arsenic trifluoride forms a stable adduct, 2AsF2 SSO, with sulfur trioxide and reacts with nitrosyl fluoride to give nitrosonium hexafluoroarsenate(V) [18535-07-4] [NO][AsFg]. 

Halide ions may attack 5-substituted thiiranium ions at three sites the sulfur atom (Section 5.06.3.4.5), a ring carbon atom or an 5-alkyl carbon atom. In the highly sterically hindered salt (46) attack occurs only on sulfur (Scheme 62) or the S-methyl group (Scheme 89). The demethylation of (46) by bromide and chloride ion is the only example of attack on the carbon atom of the sulfur substituent in any thiiranium salt (78CC630). Iodide and fluoride ion (the latter in the presence of a crown ether) prefer to attack the sulfur atom of (46). cis-l-Methyl-2,3-di-t-butylthiiranium fluorosulfonate, despite being somewhat hindered, nevertheless is attacked at a ring carbon atom by chloride and bromide ions. The trans isomer could not be prepared its behavior to nucleophiles is therefore unknown (74JA3146). 

Dolye, M., Lewittes, M. E., Roelofs, M. G. and Perusich, S. A. 2001. Ionic conductivity of nonaqueous solvent-swoUen ionomer membranes based on fluorosulfonate, fluorocarboxylate, and sulfonate fixed ion groups. Journal of Physical Chemistry B 105 9387-9394. 

When dissolved in cold fluorosulfonic acid, 1,1 -dihalogenobenzocyclopropenes ionize to benzocyclopropenyl cations (e.g., 282-286) which are stable under NMR conditions. " The same holds for l,l-dihalogenocyclopropa[( ]naphthalenes which ionize to 287-288, while the cation derived from the cyclopropa[a] isomers (289) is very short lived. No ions may be observed upon dissolving 1,1-dihalo-genocyclopiopa[fc]anthracenes (130,131) in fluorosulfonic acid. The NMR data of some fluorobenzocyclopropenyl cations are summarized in Table 4. 

Strong protonic acids such as trifluoroacetic, fluorosulfonic, and trifluoromethanesulfonic (triflic) acids initiate polymerization via the initial formation of a secondary oxonium ion... 

This type of initiation is limited hy the nucleophilicity of the anion A derived from the acid. For acids other than the very strong acids such as fluorosulfonic and triflic acids, the anion is sufficiently nucleophilic to compete with monomer for either the proton or secondary and tertiary oxonium ions. Only very-low-molecular-weight products are possible. The presence of water can also directly dismpt the polymerization since its nucleophilicity allows it to compete with monomer for the oxonium ions. 

Two equivalents of ethyl fluorosulfonate must be used (one ethylates the triflu-oroacetate ion) to avoid complications arising from ethylation of ether oxygens in the tetraglyme solvent. The product must be distilled out of the reaction mixture on a vacuum line within 5 min after addition is complete. The hydri-... 

Various NMR studies have shown that protonation of thiophene occurs at position 2. Thus the thiophenium ions (48) were prepared (73TL3929) from (47) in quantitative yield by protonation in fluorosulfonic acid at -70 °C protonation occurred exclusively at position 2. 

The 13CNMR spectrum of the 1,3-benzodioxolium ion (33), prepared in fluorosulfonic acid-sulfur dioxide solution from the methoxy compound (32), shows aromatic ring carbons deshielded 6.8 and 10.6 p.p.m. from the corresponding carbon atoms in (32). The chemical... 

Acid catalysts are required for alkane isomeiizations and all the reactions of this type probably involve carbonium ions. Optically active tertiary alkanes can be racemized by sulfuric acid at room temperature or by fluorosulfonic acids at -80 C. ... 

The high oxidation potentials of alkanes, however, make it difficult to carry out the oxidation in solvents such as acetonitrile since the first intermediates generated in these oxidations are carbonium ions, as illustrated by equations (4) and (S), Their stabilization with strongly acidic solvents like anhydrous fluorosulfonic acid often lowers the oxidation potentials of these hydrocarbons. ... 

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