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clearly_not_atara
International Hazard
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Quote: Originally posted by AJKOER  |
The aqueous solution [of FeBr3] upon concentration in the ordinary way decomposes with the precipitation of insoluble basic bromides.
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Thanks, AJKOER!
[Edited on 04-20-1969 by clearly_not_atara]
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woelen
Super Administrator
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I have done some experiments with a slightly acidified solution of Fe2(SO4)3 and KBr. It looks like there is partial oxidation of bromide to bromine.
But the reaction is far from complete. I have the impression that the redox potential of bromine and ferric ions acting as oxidizer in a solution,
containing quite some bromide ions are close to each other. Addition of bromine to iron(II) leads to partial reduction of the bromine, while addition
of bromide to iron(III) leads to partial oxidation of the bromide.
In older literature the compound Fe3Br8 is mentioned as the normally obtained compound from bromine and iron. I personally believe it is a
non-stoichiometric compound with iron(III) and iron(II) in an approximate 2 : 1 molar ratio.
I deem the use of iron(III) for making bromine not useful at all. It may be interesting to experiment with this from an academic point of view, but I
see no practical use. it would mean that only appr. 1 out opf 9 bromine atoms end up in the element, the rest remains in solution as bromide.
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AJKOER
Radically Dubious
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Woelen great experiment!
I agree on your assessment on the feasibility of the process.
Others, not convinced, may try some of the following suggestions based on my readings on advanced oxidation processes. First, use ascorbic acid
(and/or citric acid, per one source, see below) to acidify, pump in air/O2, mild heating above 60 C (which, with air may strip off any liberated
bromine), and also UV light (to assist in the recycling of transition metal ions as would also introducing copper ions to promote a redox couple
equilibrium).
If the yield is still low, I doubt if there is any further improvement possible.
Reference, a prior comment on SM:
| Quote: Originally posted by AJKOER | .......
Also, to a limited extent also the presence of citrate (or ascorbate), as I noted previously on SM (see "Generation of Hydroxyl Radicals from
Dissolved Transition Metals in Surrogate Lung Fluid Solutions" by Edgar Vidrio, et al at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2626252/), can assist in the cycling of copper ions. To quote:
"Cu(II) + Asc(n) → Cu(I) + Asc(n+1) (R3)"
[Edited on 21-5-2018 by AJKOER] |
[Edited on 17-7-2018 by AJKOER]
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