thors.lab - 10-11-2020 at 12:20
Hi,
I heard that using ferric salts can significantly improve yield in ketonic decarboxylation of carboxylate salts to produce things like butyrophenone
etc. This could be a very convenient method that doesn't require acyl chlorides which have proven to be extraordinarily hard for the amateur chemist
to acquire (seriously, I've been looking for ages and haven't found a single way to make them that's practical).
Now ferric benzoate and etc are pretty hard to just buy. But sodium benzoate is readily available. I'm not too familiar with this type of inorganic
reaction so I need a little help figuring out how or if I could convert these sodium salts to ferric salts.
Thanks,
DraconicAcid - 10-11-2020 at 13:32
One would normally mix ferric chloride/nitrate/whathaveyouate with sodium benzoate in a stoichiometric ratio, and expect the iron compound to
precipitate out. However, ferric compounds are notorious for hydrolyzing, so you'd be likely to get a basic ferric benzoate, or possibly just a mix
of rust and benzoic acid.
clearly_not_atara - 10-11-2020 at 15:14
I thought it was the ferrous salts?
Anyway you could start from ferrous sulfate and calcium benzoate or similar -- precipitating CaSO4 sucks of course though. Alternatively, if ferrous
tartrate is available, you can precipitate potassium bitartrate by using one component as the acid:
Fe(O2CCHOH)2 (aq) + H2(O2CCHOH)2 (aq) + RCO2H (aq) + KOBz (aq) >> "Fe(O2CR)(OBz)" (aq) + KH(O2CCHOH)2 (s)
For this I would try precipitating iron (II) carbonate from a solution of any iron (II) salt and dissolving this in a slight molar excess of boiling
aqueous tartaric acid; since the salt is attacked by air, the solution should be used immediately. However if you can buy ferrous tartrate itself that
would of course be easier.
[Edited on 10-11-2020 by clearly_not_atara]
karlos³ - 10-11-2020 at 15:16
Look for posts from organikum, somewhere he describes exactly that very detailed.