J. Colin Tatlow

The fluorination of ethane and ethene over potassium tetrafluorocobaltate(III) and cobalt trifluoride

Abstract Fluorination of ethane and ethene with KCoF4 and CoF3 over a range of temperatures gave, in all cases, mixtures of polyfluoroethanes, C2H6-nFn n = 1–6, with very little CC bond cleavage. Apart from an initial easy saturation of ethene to CH2FCH2F, both substrates had a similar reactivity. Hydrogen appeared to be replaced by fluorine almost randomly in all fluorinations. CH2FCH2F is a stable compound, contrary to literature reports.

Reactions of olefinic double bonds with polyfluoroalkyl radicals generated electrochemically

The addition of polyfluoroalkyl radicals, generated electrochemically, to olefinic double bonds, illustrates a new method of obtaining a number of novel polyfluoroalkyl derivatives.

Fluorination of nitriles over cobalt trifluoride and potassium tetrafluoro-cobaltate

Fluorinations of acetonitrile and propiononitrile by cobalt trifluoride and potassium tetrafluorocobaltate leave the nitrile groups mainly intact, as expected from their high ionization potentials. Major products from acetonitrile are CH2F·CN (main) and CHF2·CN, and from propiononitrile, CH3·CHF·CN (main), CH3·CF2·CN, CH2F·CHF·CN, and CH2F·F·CF2·CN, with α-fluorination strongly predominating. Succinonitrile and fumaronitrile both give a mixture of difluoro-fumaro- and -maleo-nitriles.

Fluorinations with complex metal fluorides. Part 4. An improved synthesis and the oxidation of hexadecafluorobicyclo[4.4.0]dec-1(6)-ene

Fluorination of naphthalene, tetralin, and decalin with caesium tetrafluorocobaltate(III) yielded two major products identified as hexadecafluorobicyclo[4.4.0]dec-1(6)-ene and dodecafluorotetralin. Oxidation of the alkene gave cis-hexadecafluorobicyclo[4.4.0]decane-1,6-diol. Some reactions of this diol (e.g. with diazomethane, benzoyl chloride, and thionyl chloride) are described.

Some reactions of tetrafluoroethylene oligomers

Abstract As part of a programme to prepare and evaluate a series of perfluoro- chemicals for use as inert fluids, the fluorinations of some tetrafluoroethylene oligomers over cobalt (III) fluoride have been studied. Fluorination of perfluoro-3,4-dimethylhex-3-ene (tetramer) and perfluoro-4-ethyl-3,4-dimethylhex-2-ene (pentamer) over CoF 3 at 230°C and l45°C respectively afforded the corresponding saturated fluorocarbons however, at 250°C, pentamer gave predominantly the saturated tetramer. The thermal behaviour of these saturated fluorocarbons alone and in the presence of bromine and toluene has been studied. Pyrolysis of pentamer over glass beads at 500°C gave perfluoro-1,2,3- trimethylcyclobutene and isomers of perfluoro-2,3-dimethylpenta-1,3- diene. Under similar conditions perfluoro-2-(1-ethyl-1-methylpropyl). 3-methylpent-1-ene (hexamer) gave perfluoro-1-methyl-2-(1-methyl- propyl)-cyclobut-1-ene and perfluoro-2-methyl-3-(1-methylpropyl)-buta- 1,3-diene. These reactions and the structural elucidation of the products will be discussed.

Reactions of octafluoroacridone and related compounds

A new route to polyfluoroacridones is described and the substitution reactions of octafluoroacridone with methoxide ion are discussed, the position of substitution being confirmed by alternative synthesis from an amino-methoxy-octafluorobenzophenone. From octafluoroacridone was prepared 9-chloro-octafluoroacridine, but not nonafluoroacridine, owing to its ready hydrolysis. Polyfluoroacridones give stable sodium salts, isolable in crystalline form.Ready demethylation of methyl polyfluoroaryl ethers occurred with concentrated sulphuric acid when a carboxy-group or hydrogen atom was para to the methoxy-group; this is explained in terms of protonation of the para ring carbon atom.

Highly fluorinated heterocycles. Part XIII. Fluorination of 1-methylpyrrole and some reactions of derived compounds

1-Methylpyrrole has been fluorinated over potassium tetrafluorocobaltate(III) and cobalt(III) fluoride to yield octafluoro-1-methylpyrrolidine (I), octafluoro-1-fluoromethylpyrrolidine (II), 3H-heptafluoro-1-methylpyrrolidine (III), 3H,4H-hexafluoro-1-methylpyrrolidine (IV), 3H-heptafluoro-1-fluoromethylpyrrolidine (V), and 3H,4H-hexafluoro-1-fluoromethylpyrrolidine (VI). The proportions obtained depend on the temperature and the fluorinating agent. Refluorination of (I) over CoF3 yielded perfluoro-1-methylpyrrolidine (VII), 1-difluoromethyloctafluoropyrrolidine (VIII), and (II). Dehydrofluorination of (III) yielded hexafluoro-1-methyl-Δ3-pyrroline (IX), which reacted with cyclopentadiene to yield an endo-exo mixture of 2,6-difluoro-4-methyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione (X) and in an attempted reaction with perfluorocyclohexa-1,3-diene gave 3,4-difluoro-1-methyl-Δ3-pyrroline-2,5-dione (XI). Reactions of (I) and (IV) with concentrated sulphuric acid gave the corresponding diones by hydrolysis of the α-CF2 groups. Treatment of (VI) with aluminium chloride in methylene chloride gave 1-chloromethyl-3H,4H-hexafluoropyrrolidine and reaction of (II) with sodium ethoxide gave 1-ethoxymethyloctafluoropyrrolidine.

Fluorinations with potassium tetrafluorocobaltate(III). Part VI. Fluorination of pyridine and 4-methylpyridine

Pyridine has been fluorinated over KCoIIIF4 to give a mixture largely of ring-opened products. The main components isolated were (Z)-undecafluoro-2-azahex-2-ene (I), (Z)-2H-1-bistrifluoromethylaminotetrafluoroprop-1-ene (II), (E)-2H-1-bistrifluoromethylaminotetrafluoroprop-1-ene (III), (Z)-5H-decafluoro-2-azahex-2-ene (IV), (2Z,4E)-4H,5H-heptafluoro-2-azahexa-2,4-diene (V), (2Z,4Z)-5H-octafluoro-2-azahexa-2,4-diene (VI), (2Z,4E)-5-bistrifluoromethylamino-octafluoro-2-azahexa-2,4-diene (VII), (2Z,4Z)-5-bistrifluoromethylamino-octafluoro-2-azahexa-2,4-diene (VIII), and 3H-1-difluoromethylheptafluoropyrrolidine(IX). In a similar manner, fluorination of 4-methylpyridine gave the analogous compounds (Z)-5-trifluoromethyldecafluoro-2-azahex-2-ene (X), (Z)-5-trifluoromethyloctafluoro-2-azahexa-2,4-diene (XI), (Z)-5-methyldecafluoro-2-azahex-2-ene (XII), and (Z)-5-difluoromethyldecafluoro-2-azahex-2-ene (XIII) as major components.