DFliyerz
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Protonation of Sulfuric Acid
This is in no way a practical question like I usually ask, but a theoretical one.
Sulfuric acid can protonate nitric acid to form the nitronium cation because sulfuric acid is stronger than nitric. However, couldn't you protonate
sulfuric acid with an even stronger acid? If so, what would the resulting cation be called? Also, what would the conjugate acid (assuming I'm using
the term correctly) of acetic acid be called?
[Edited on 1-19-2016 by DFliyerz]
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BromicAcid
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H<sub>2</sub>SO<sub>4</sub> + HClO<sub>4</sub> <----> ClO<sub>4</sub><sup>-</sup> +
(HO)SO<sub>2</sub>(OH<sub>2</sub> <sup>+</sup>
I wrote the above example of what you are talking about based on what I have heard over and over. Super acids are acids that can protonate sulfuric
acid, of which perchloric acid is noted as being stronger than sulfuric acid. From there water could possibly under some circumstances fall off
leaving what I think you are interested in:
(HO)S<sup>+</sup>O<sub>2</sub>
Interestingly enough when I was looking up the name of our sulfur compound above, one of my references<sup>1</sup> "concluded that the two
components of the system do not interact". It is true as well that I was unable to find any perchlorate salts of sulfuric acid. In the previous
reference however they used 'pure' sulfuric and perchloric acids, and measured the interaction through conductivity. Perhaps if they had instead used
some anhydride of perchloric acid they would have pushed the equilibrium. Going the other way, adding sulfur trioxide to anhydrous perchloric acid
can apparently produce explosions.
Anyway, I am getting off track. According to Wiki (and we all love Wiki) the self ionization of sulfuric acid to pyrosulfuric acid (disulfuric acid)
helps put the brakes on protonation of the free acid in some cases by generating its own hydronium ions.
2 H<sub>2</sub>SO<sub>4</sub> <------> [H<sub>3</sub>O]<sup>+</sup> +
[HS<sub>2</sub>O<sub>7</sub>]<sup>−</sup>
Again, not what you are interested in. However, taking a minute to actually search for the compounds listed in the wiki article yields their
literature roots<sup>2</sup>, and are you ready for it:
[H<sub>3</sub>SO<sub>4</sub>]<sup>+</sup>[SbF<sub>6</sub>]<sup>-</sup>
Trihydroxyoxosulfonium Hexafluoroantimonate
It's certainly not poetic but there it is. I would be interested in searching Mellor to see if there is a more archaic name for these compounds.
Sometimes even when something has been only recently prepared people have assumed they produced it in the past and given it a name in the meantime.
As for your second question, are you asking what prontated acetic acid would be called? Usually for an acid you would ask for the conjugate base
(acetate in this case) but if you want the protonated form of the acid it's not really the conjugate. When you protonate acetic acid it will probably
prontate at the carboxyl group. From there however it will probably resonate all over the place. Not sure if there are isolated protonated acetic
acid derivatives so there might not be trivial names for them.
1 - Perchlorates: Their Properties Manufacture and Uses, ACS Monograph Series No. 146, Reinhold (1960)
2 - Minkwitz, R., Seelbinder, R. and Schöbel, R. (2002), Protonated Sulfuric Acid: Preparation of Trihydroxyoxosulfonium Hexafluoroantimonate
H3SO4+SbF6−. Angew. Chem. Int. Ed., 41: 111–114. doi:10.1002/1521-3773(20020104)41:1<111::AID-ANIE111>3.0.CO;2-6
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