Bedlasky - 19-12-2020 at 13:21
Hi.
I decided to start topic about superacids. There are probably not much people, which have experience with superacids, but this is quite interesting
part of chemistry.
I plan to try make weakly superacidic systems, which everyone can make in home - 96% H2SO4/PO3-/B2O3 and 96% H2SO4/P4O10/B2O3. Metaphosphate can you
make by dehydrating dihydrogenphosphate, boric oxide by dehydrating boric acid. Because I have access to spectrophotometer, I will try to measure
absorbance of these mixtures using nitrobenzene as indicator and calculate Hammett acidity function. I will post there later my results.
I came across this video about fluoroantimonic acid today:
https://www.youtube.com/watch?v=UWBNcMyfiGQ
Very interesting is reaction between isopentane, benzene, fluoroantimonic acid and potassium permanganate. Isopentane is dissolved by fluoroantimonic
acid to form carbocation:
2HF + SbF5 <--> H2F+ + [SbF6]-
[SbF6]- + SbF5 <--> [Sb2F11]-
C5H12 + H2F+ <--> C5H13+ + HF
C5H13+ undergo electrophylic aromatic substition with benzene:
C6H6 + C5H13+ + HF <--> C6H5C5H11 +
H2 + H2F+
Isopentylbenzene than reacts with aqueous potassium permanganate to form benzoic acid:
7C6H5C5H11 + 30MnO4- + 30H3O+ --> 11
C6H5COOH + 30MnO2 + 68H2O
Here is link to very interesting document about superacids and measuring H0:
https://macsphere.mcmaster.ca/bitstream/11375/19972/1/Peel_T...
DraconicAcid - 19-12-2020 at 14:51
I used to work with triflic aid. Unpleasant stuff.
Fulmen - 19-12-2020 at 15:08
I have worked with oleum, seeing it vaporize paper on contact was enough for me. Check please.