what would be the best way to extract either iodine or iodide ion from Triiodobenzoic acid?
obviously it can't be as simple as if it was an inorganic, i.e. just pass chlorine gas over it.
a protocol that gave iodide would be best. any ideas?Nicodem - 18-5-2007 at 07:46
You can not extract either iodine or iodide from any of the two possible triiodobenzoic acids since it is a compound and not a salt or mixture.
Probably the simplest way is to mix it intimately with Na2CO3 and burn it in oxygen in order to obtain a mixture of Na2CO3 and NaI. Then procede as
you please.
PS: I hope you realize the extreme stupidity of doing this given that even the cheapest regioisomer, 2,3,5-triiodobenzoic acid, is at least 6 times
more expensive than iodine itself while the 3,4,5 regioisomer runs for 43USD per 1 g!Maya - 18-5-2007 at 09:16
Yes , the 2,3,5- triiodobenzoic acid is what I meant
and I would prefer iodide than iodine
But burning is SOOOOoooo inefficient and wasteful, I was hoping there are alternatives
And its not stupidity when expense is no issue and you have gallons of it for free................
[Edited on 18-5-2007 by Maya]not_important - 18-5-2007 at 10:27
Halogens on aromatic rins are typically difficult to remove; the main exception being when there are several electron withdrawing groups such as nitro
or cyano on the ring.
If that's not the case then pulling halogens off means using pretty extreme conditions. Sodium in liquid ammonia, aqueous NaOH at +200 C, distilling
with zinc dust (this can get exciting), full oxidation of the ring in a alkaline environment.
Why not try to trade it with someone from inorganic iodide? If you get it for free you can set the price low enough that someone else will be willing
to do the work of rounding up some CaI2 or similar.Maya - 18-5-2007 at 13:54
What exactly do you think distilling with Zinc would do?
I've got lots of sodium , but I think that route is too perilous.
oxidation in an alkaline environment? like CaOH?
......Why not try to trade it with someone from inorganic iodide? If you get it for free you can set the price low enough that someone else will be
willing to do the work of rounding up some CaI2 or similar..........
Sure, in a minute , but who would want to recycle this???
[Edited on 18-5-2007 by Maya]
[Edited on 18-5-2007 by Maya]Dr. Beaker - 21-5-2007 at 14:35
In three words:
Metal-halogen exchange.
btw - burning in alkaline environment wont help, since HI is readly oxidized by O2. you may even get iodates/periodates...
[Edited on 22-5-2007 by Dr. Beaker]UnintentionalChaos - 21-5-2007 at 17:31
What is the triiodobenzoic acid used for that you can get such large quantities of it?DeAdFX - 21-5-2007 at 19:09
Why not oxidize the molecule using a basic 10-35% solution of hydrogen peroxide[with some ferrours/ferric ions]. You should end up with
CO2/H2O/Iodine in various oxidization states....Maya - 22-5-2007 at 03:18
<<< In three words:
Metal-halogen exchange >>>
What type of metal is rec'd, and environment?
<<< What is the triiodobenzoic acid used for that you can get such large quantities of it? >>>
Its derivatives are used as imaging agents but the application used by me is for density gradientsnot_important - 22-5-2007 at 08:56
Quote:
Originally posted by Maya
<<< In three words:
Metal-halogen exchange >>>
What type of metal is rec'd, and environment?
Most commonly done with lithium alkyls :
ArI + BuLi => ArLi + BuI
Sometimes it can be done via making the Grignard :
RI + Mg => RMgI , + H2O => RH + Mg(I,OH) + 1/2 H2
In either case you'll need to make the sodium or lithium salt of the carboxylic acid first, and really dry the resulting salt.
This is a rather expensive way to recover iodine. If it were I, I'd make a melt of mixed sodium and potassium hydroxides, and slowly add the
3I-benzoic mixed with sodium and potassium nitrates. The nitrates oxidise the organics, the excess base snags the iodine, and mixed hydroxides have a
lower melting point which helps keep down loss of iodine.
Alternatively, heating a tube filled with Na2CO3 and heated to ~700 C, blowing a slow stream of air through it, then adding the 3I-benzoic such that
the airflow carries it through the tube, will do the same thing. CO2 and H2O out, the Na2CO3 and the exit end of the tube acts to absorb any iodine
that comes off - which means you have to stop before all the Na2CO3 is reacted. Cool, then extract with warm acetone to dissolve out the NaI.
