Chemistry Reference
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shown in Eq. 6.22 [61]. In this double ionic
system, the cationic intermediate generated
from the phthalide was expected to have a TfO
counter anion (activated cation A in Eq. 6.22 ),
which readily reacted with F to provide the
fluorinated phthalide in good to excellent yield.
(6.22)
The viscosity of ionic liquid fluoride salts is
higher than that of ordinary organic solvents,
therefore the mass transport of substrates to
the anode surface from the bulk liquid is slower
than in organic solvents, which is unfavourable
for electrolytic reactions.
As mentioned in section 6.11, it is known that
ultrasonication greatly enhances mass
transport from bulk to electrode surface. This
effect can also be applied to an ionic liquid
system as the efficiency of anodic fluorination
in ionic liquid fluoride salts is markedly
increased, as shown in Eq. 6.23 [62]. Notably,
anodic difluorination of ethyl
α-(phenylthio)acetate proceeds efficiently even
in readily oxidizable ionic liquid, Et 3 N-3HF,
which is not suitable for difluorination.
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