Fluorine sulphuric acid

The most widely used reactions are those of electrophilic substitution, and under controlled conditions a maximum of three substituting groups, e.g. -NO2 (in the 1,3,5 positions) can be introduced by a nitric acid/sul-phuric acid mixture. Hot cone, sulphuric acid gives sulphonalion whilst halogens and a Lewis acid catalyst allow, e.g., chlorination or brom-ination. Other methods are required for introducing fluorine and iodine atoms. Benzene undergoes the Friedel-Crafts reaction. ... 

Ozone is formed in certain chemical reactions, including the action of fluorine on water (p. 323) and the thermal decomposition ofiodic(VII) (periodic) acid. It is also formed when dilute (about 1 M) sulphuric acid is electrolysed at high current density at low temperatures the oxygen evolved at the anode can contain as much as 30% ozone. 

Hydrogen fluoride is the most important compound of fluorine. It is prepared in the laboratory, and on the large scale, by the reaction of calcium fluoride with concentrated sulphuric acid. ... 

The principal applications of these plastics arose from their very good chemical resistance, as they are resistant to mineral acids, strong alkalis and most common solvents. They were, however, not recommended for use in conjunction with oxidising acids such as fuming nitric acid, fuming sulphuric acid or chlorosulphonic acid, with fluorine or with some chlorinated solvents, particularly at elevated temperatures. 

Chromic acid, nitric acid, hydroxyl-containing compounds, ethylene glycol, perchloric acid, peroxides, or permanganates Concentrated nitric and sulphuric acid mixtures Chlorine, bromine, copper, silver, fluorine or mercury Carbon dioxide, carbon tetrachloride, or other chlorinated... 

Lead will resist chlorine up to about 100°C , is used for dry bromine at lower temperatures and is fairly resistant to fluorine . Hydrofluoric acid does not passivate lead, so lead should not be used in this environment. Lead is very resistant to sulphur dioxide and fairly resistant to sulphur trioxide, wet or dry, over a wide temperature range . ... 

The reaction between F.E.A. and manganese dioxide and sulphuric acid was investigated initially with a view to preparingthe corresponding fluorinated acetal. It soon became apparent that the isolation of the hitherto undescribed fluoroacetaldehyde might be possible in this experiment, and accordingly attention was directed to that end. 

Ethyl 10-fluorodecanecarboxylate was readily prepared by the fluorination of the corresponding bromo ester prepared by esterifying the acid with ethyl alcohol and sulphuric acid. 

The alcoholysis of (XV)-(XVI) was effected by boiling with absolute alcohol and sulphuric acid. The standard technique was adopted for the fluorination. 

Bromo [ F]fluoride is different from the other electrophilic radiolabelling agents discussed so far in the sense that the electrophilic part of the molecule is not fluorine but bromine. This is reflected by its synthesis from nucleophilic p F]fluoride and it can be obtained in high specific radioactivity. Bromo p F]fluoride was developed for fluorine-18 labelling of steroids (see Section 3.2) [64-66]. It was prepared (Scheme 11) in situ by reaction of dried p Fjfluoride with 1,3-dibromo-5,5-dimethylhydantoin and sulphuric acid in dichloromethane containing also the substrate. 

Hence, in highly acidic media, fluorine may act as a very powerful and selective electrophile and, by this method, 2,4-difluorobenzoic acid, which is highly deactivated towards electrophilic attack, can be fluorinated in concentrated sulphuric acid to such an extent that 2,3,4,5-tetrafluoro- and even small amounts of pentafluoro-benzoic acid are produced [146,147]. 

Solid sulphur, selenium, and tellurium inflame in fluorine gas at ordinary temp. sulphur burns to the hexafluoride, SF6. The reactivity of sulphur or selenium with fluorine persists at —187°, but tellurium is without action at this temp. Hydrogen sulphide and sulphur dioxide also burn in the gas—the former produces hydrogen fluoride and sulphur fluoride. Each bubble of sulphur dioxide led into a jar of fluorine produces an explosion and thionyl fluoride, S0F2, is formed but if the fluorine be led into the sulphur dioxide, there is no action until the sulphur dioxide has reached a certain partial pressure when all explodes. If the fluorine be led into an atm. of sulphur dioxide at the temp, of the reaction, sulphuryl fluoride, S02F2, is formed quietly without violence. Sulphuric acid is scarcely affected by fluorine. 

Sulphuric acid is oxidised to permonosulphuric, perdisulphuric and fluorosulphonic acids when an ice-cold aqueous solution is treated with fluorine. In addition to the foregoing products, ozone and a very unstable compound believed to be a tetroxide (S04 or S2Os) are also produced.5 A similar oxidation occurs when fluorine is passed into cold solutions of alkali sulphates or hydrogen sulphates. 

Conversion of the separated fluorides into the corresponding oxides is effected by boiling with concentrated sulphuric acid until free from fluorine, and then hydrolysing the product by boiling with water. Alternatively, the hydrated acids are precipitated by the addition of ammonia to the solutions of the double fluorides.4 Niobium pentoxide, Nbg05, or tantalum pentoxide, TaaOs, is obtained on ignition of the precipitated hydrate. 

The described cleavage of organic groups from the silicon atom by interaction with sulphuric acid enables exchange of the phenyl group for chlorine or fluorine ... 

On the basis of eqn. (45) it would be expected that nitryl fluoride in sulphuric acid is a nitrating agent (besides also possessing fluorinating and sulpho-fluorinating effects). 

Fluorine decomposes water in the cold with such vigour that a portion of the liberated oxygen is ozonised. By passing a current of fluorine into water maintained at 0° C., Moissan was able to obtain a supply of oxygen containing 14-4 per cent, of ozone.6 Small yields are obtained by the action of concentrated sulphuric acid upon powerful oxidisers such as barium peroxide, potassium bichromate, or permanganate. 

It is attacked when heated in chlorine or fluorine. In air it tarnishes at dull red heat. Cold nitric acid and aqua regia attack it caustic alkalies slowly act upon it whilst hydrochloric and sulphuric acids are without action.1... 

Highly fluorinated ketones show some unusual keto-enol phenomena [122]. Remarkably, the pair 8.25A and 8.25B in Figure 8.25 cannot be equilibrated by acid or base the enol 8.25A, for example, can be distilled from concentrated sulphuric acid. In the presence of base, aldol condensation occurs faster than equilibration. 

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