[lukas.stib]

Hello chemists,

please give me an advice. I want to make propionic acid by reacting sodium propionate with acid. I have 96% H2SO4, but I don't want to use it because I'm afraid it will destroy my propionate. It's already happened to me with sodium acetate, which turned black because H2SO4 dehydrated into elements. I don't know what acid would be effective. I have 85% phosphoric acid, can I use it? I want to get a lot of concentrated propionic acid, will the problem be 85% phosphoric acid?

Thank you. Lukáš S.

[Hunter2]

Use diluted sulfuric acid 10 to 20 %.

[lukas.stib]

But it will be too much water ...

[Hunter2]

Of course you have to do Destillation.

[lukas.stib]

And 85% phosphoric acid? I think this is better. Much less water and phosphoric acid also certainly reacts and has no destructive effects like H2SO4. Or 35% HCl is too good I think...

[Hunter2]

You can do.

[Aldebaran]

Bear in mind propanoic acid forms a constant boiling point mixture with water. I note you want to make a lot of the concentrated acid so unless you particularly want to experiment with methods of further concentrating the azeotropic mixture it might be easier to just buy the concentrated acid.

[lukas.stib]

OK, thank you. I can't get propionic acid anywhere in the Czech Republic, so I wanted to try it from its sodium salt. I wanted it for esters, so maybe it would be more appropriate.

[Babcock_Hall]

One might be able to desalt a mixture containing sodium ions and an anion with a mixed-bed ion exchange resin.  I am not sure how practical this is.

[lukas.stib]

And what about a mixture of propionic acid and water to dry some salt? Sodium sulfate?