Sulphovinic acid

I made this chemical last weekend. It's interesting stuff. I plan to use it to make sodium ethylsulphate and eventually diethyl thioether.

Here's some information about it: sulphovinic acid, also known as ethoxysulphonic acid, ethyl bisulphate, ethylsulphuric acid or simply ethyl sulphate is an acid with the formula C2H6SO4. It exists as a colourless liquid at room temperature and pressure.

This is how I made it:

I started by adding some ethanol and twice as much sodium bisulphate by molar mass to a large round bottom flask. I then refluxed this mixture for an hour after which not much had changed.

I decided this was due to poor mixing of the reactants. To combat this I refluxed the mix for another hour while shaking the appuratus to keep the sodium bisulphate in a suspension in the ethanol. About 30 minutes into this I noticed a fine precipitate of presumably sodium sulphate forming.


It's important that the reflux temperature does not exceed 140 C as this will favor the formation of diethyl ether over sulphovinic acid.

As soon as I noticed that no more sodium sulphate was forming, I plunged the round bottom flask containing the reaction mix into an ice bath. This allows the sodium sulphate to form a hydrate with the water produced in the reaction. This is an important step as the sulphovinic acid produced in the reaction decomposes on contact with water. Anyway, I then filtered the mixture to remove the sodium sulphate decahydrate precipitate and I was left with clear liquid (presumablely sulphovinic acid).

I haven't had a chance to test the sulphovinic acid yet. I'll post once i've tested it.

2 NaHSO4 + C2H5OH ==> C2H6SO4 + 2 NaSO4 + H2O