C—F link

This reaction depends upon the great difference in reactivity between the bromine atom and the fluorine atom in bromofluoroethane. The relative firmness of the C—F link is again referred to in Chapter vn. 

In this work on compounds containing the C—F link, it was obviously desirable to prepare 2-fluoroethanol, both for toxicity tests on the compound itself, and as a starting material for the production of other fluorine compounds. Swarts1 was unable to obtain 2-fluoroethanol by the action of silver fluoride or mercuric fluoride on either ethylene chlorohydrin or ethylene bromohydrin. He obtained acetaldehyde in each case. He ultimately obtained fluoroethanol in very poor yield by the indirect method of hydrolysing fluoroacetin (from bromoacetin and mercuric fluoride) for 80 hr. with dilute mineral acid. 

A wide variety of compounds containing the C—F link has been described in this Chapter, and it is now convenient to classify them according to their physiological activity. In general, two types of assessment of animal toxicity have been made (a) by inhalation (liquids) and given as l.c. 50 in mg./l. (b) by injection (liquids and solids) and given as l.d. in mg./kg. of body weight. 

In the next chapter a description will be given of the synthesis of further highly toxic compounds containing the C—F link, which lend support to the views expressed above. 

Working with kidney homogenates from guinea-pigs, Peters has isolated an inhibitor containing a C—F link as the result of the enzymic action of kidney upon fumarate and fluoroacetate. This inhibitor is almost certainly fluorocitrate because... 

The formation of fluoroacetate in the plant is of very great interest and the question arises how the plant enzymes build up the C—F link. Equally interesting is the mechanism by which fluoroacetate is destroyed. Throughout the aeons of time, in which the plant has built up fluoroacetic acid, the accumulation... 

The C—F link in certain aromatic amines has been broken by peroxidase, p. 148... 

The two types of fluorine compounds are (a) compounds containing the P—F link, e.g. the phosphorofluoridates (b) compounds containing the C—F link and known collectively as fluoroaoetates. 

The first additions to a fluoro-ene were of chlorine and bromine to the C = C bond of allyl fluoride. Meslans used silvcr(I) fluoride, arsenic(III) fluoride, zinc(II) fluoride and antimony(III) fluoride to convert21 acetyl chloride to the fluoride, which was shown to have a reactive C — F bond. The first reaction on a saturated fluoride to retain the C —F link was by Collie.22 Tetramethylammonium fluoride was transformed to fluoromethane on heating which was then converted to chlorofluoromethane by treatment with chlorine. 

OTHER COMPOUNDS CONTAINING THE C-F LINK Amines, as might be expected, take the following course F[CHj],CH H,---- F[CHj],CH=NH ---- FlCH,]sCHO --> F[CH,]jCOOH. 

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