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The reaction of F 2 with organic compounds is, however, highly exothermic and can lead to non-selective fluorinations and C–C cleavage, as well as explosions. [6] Only a few selective radical fluorination methods have been reported. [7] [8] The use of fluorine for radical fluorination is mainly limited to perfluorination reactions. [5]
The direct fluorination of hydrocarbons with F 2, often diluted with N 2, is useful for highly fluorinated compounds: R 3 CH + F 2 → R 3 CF + HF. Such reactions however are often unselective and require care because hydrocarbons can uncontrollably "burn" in F 2, analogous to the combustion of hydrocarbon in O 2. For this reason, alternative ...
The mechanism of electrophilic fluorination remains controversial. At issue is whether the reaction proceeds via an S N 2 or single-electron transfer (SET) process. In support of the S N 2 mechanism, aryl Grignard reagents and aryllithiums give similar yields of fluorobenzene in combination with N-fluoro-o-benzenedisulfonimide (NFOBS), even though the tendencies of these reagents to ...
The species KHF 2 is relatively low melting, a good electrolyte, and an effective source of fluorine. The technology is sometimes called “CAVE” for Carbon Anode Vapor Phase Electrochemical Fluorination and was widely used at manufacturing sites of the 3M Corporation. The organic compound is fed through a porous anode leading to exchange of ...
In reductive hydrodefluorination the fluorocarbon is reduced in a series of single electron transfer steps through the radical anion, the radical and the anion with ultimate loss of a fluorine anion. An example is the conversion of pentafluorobenzoic acid to 3,4,5-tetrafluorobenzoic acid in a reaction of zinc dust in aqueous ammonia.
Consider acetic acid and its mono-, di-, and trifluoroacetic derivatives and their pK a values (4.74, 2.66, 1.24, and 0.23 [note 2]); [28] in other words, the trifluoro derative is 33,800 times stronger an acid than acetic. [29] Fluorine is a principal component of the strongest known charge-neutral acid, fluoroantimonic acid (H 2 FSbF 6). [30]
2 KMnO 4 + 2 KF + 10 HF + 3 H 2 O 2 → 2 K 2 MnF 6 + 8 H 2 O + 3 O 2 ↑ 2 K 2 MnF 6 + 4 SbF 5 → 4 KSbF 6 + 2 MnF 3 + F 2 ↑. Christe later commented that the reactants "had been known for more than 100 years and even Moissan could have come up with this scheme." [178] As late as 2008, some references still asserted that fluorine was too ...
Electrophilic substitution reactions typically make use of [18 F] F 2 as a precursor which can then be added to an array of molecules such as alkenes, aromatic rings, and carbanions [21]. However, methods utilizing [ 18 F] F 2 are at a disadvantage due to the loss 50% of the input activity in the form of [ 18 F] F − . [ 4 ]