Sciencemadness Discussion Board

Iodine from tincture

paulll - 24-6-2021 at 00:38

I'm trying to drop Iodine from tincture and not having much luck.
So this evening I charged a beaker with 100ml of tincture of Iodine(2.5%), added 40ml Muriatic (ie, technical grade conc. HCl), which gave off a bit of vapour and a mild exotherm. Threw in 120ml of 3% H2O2, gave it a swirl and let it be for a few hours.
Zero precipitate.
Going back in my lab book, I did the same thing, with Iodine tincture from a different vendor, H202 from a different vendor, and a different stock of Muriatic from the same vendor, in a 1:1:1 ratio, on 11 Jan, same result; Zero precipitate.
The glass is clean (pristine on the first try), everything's at room temp.

I'm looking at a 500ml beaker filled with what looks like dilute tincture of Iodine, there might be vague bits of floaty precipitate near the bottom, but there certainly is not any collectible Iodine at the bottom.

I assume I'm making an obvious fuck-up here, I'd be much obliged if someone would point it out.

Cheers:)

Sulaiman - 24-6-2021 at 03:22

Is it definitely "iodine tincture" https://en.wikipedia.org/wiki/Tincture_of_iodine
or is it "Povidone-iodine" https://en.wikipedia.org/wiki/Povidone-iodine

If its povidone then I've seen relevant threads here on SM
https://www.google.com/search?q=site%3Asciencemadness.org+po...

not tried myself.

Triflic Acid - 24-6-2021 at 05:35

If you want iodine, try to start with iodide salts, much better. But, no matter which method you choose, if you try to make anhydrous iodine by drying it with sulfuric acid, make sure that you precool the wet iodine and the acid. Half of my iodine sublimated away because I added rt acid to the iodine and the temperature jumped. But it did produce some nice purple iodine fumes :P

[Edited on 24-6-2021 by Triflic Acid]

paulll - 24-6-2021 at 15:04

Definitely tincture: Alcohol, water, 25mg/ml Iodine, 19mg/ml KI.

Triflic Acid, I might do that but I'd rather do it with stuff I can buy down the street than with stuff I'd be ordering from Poland and waiting 3 weeks for - and I've little reason to suspect that that wouldn't go just as wrong as the last two runs.

arkoma - 25-6-2021 at 10:47

I2 from KI is a breeze.

Triflic Acid - 25-6-2021 at 13:17

I don't see why you need to order from poland, a decent supplements store might sell it as an iodide supplement.

paulll - 25-6-2021 at 17:16

Quote: Originally posted by arkoma  
I2 from KI is a breeze.

It's a breeze to get it from tincture, too, but here I am :p


Keras - 26-6-2021 at 00:10

As far as I know, iodine tincture is just iodine dissolved in alcohol. Why don’t you just try to heat it and collect sublimed iodine?

That being said, as the others remarked, it’s not a very efficient way to get iodine.

Sulaiman - 26-6-2021 at 02:47

I think that I'd try bubbling chlorine through the solution,
(e.g. TCCA + HCl)
should be able to get a good yield I think,
if you are comfortable with the chlorine gas.

MidLifeChemist - 27-6-2021 at 20:26

What you are trying works for potassium iodide, not iodine dissolved in alcohol afaik.

draculic acid69 - 27-6-2021 at 21:29

Perhaps the alcohol is causing the problem.
Anyways here is a possibly different approach:
Take tincture and add NaOH solution to tincture
forming sodium iodide and iodate or hypoiodite
or whatever it is then evaporate off the alcohol
leaving a basic clear(should be clear after the naoh
bonded with the free iodine) solution of water+iodide salts
which can be acidified and oxidised to free iodine in
a (probably) cleaner and higher yeilding way.
No alcohol should mean better precipitation.
After saying all that I should point out that
If you are going to try this variation U might as well just start with povidone iodine solution and proceed as the following Video shows:
https://m.youtube.com/watch?v=FNf8PSda7iI

Or this one:
https://m.youtube.com/watch?v=VeQ_BDWm7ls

Povidone iodine can be bought cheaper and in larger amounts than the tincture.

[Edited on 28-6-2021 by draculic acid69]

paulll - 28-6-2021 at 09:54

Quote: Originally posted by Sulaiman  
I think that I'd try bubbling chlorine through the solution,
(e.g. TCCA + HCl)
should be able to get a good yield I think,
if you are comfortable with the chlorine gas.


I still have the solution, I think I'll try this before I waste it.

Quote:
If you are going to try this variation U might as well just start with povidone iodine solution

I had considered that but with povidone being thin on the ground right now (there's an empty spot for it on the shelf at every local pharmacy, has been for months)I thought I'd have a go at the tincture - which *looked* a shade more straightforward anyway. I think I'll be keeping an eye out for povidone and going down that route.

Thanks for the feedback, everyone.

[Edited on 28-6-2021 by paulll]

recovery of iodine from residues

S.C. Wack - 28-6-2021 at 19:22

Quote: Originally posted by draculic acid69  
Perhaps the alcohol is causing the problem.
Anyways here is a possibly different approach:
Take tincture and add NaOH solution to tincture


Great idea...if one wants to make iodoform.

Sounds like a lot of HCl. And H2O2...but I didn't do the math...it's mentioned as I suspect that chlorine reacts with iodine, and alcohol. This may interest someone:

j_soc_chem_ind_18_560_1899.gif - 47kB

paulll - 28-6-2021 at 23:57

Interesting read, S.C., where's that from?
Anyway I blew a couple of moles of Chlorine through it (which was interesting, I'm getting to working outside as much as possible and the mosquitoes were insane this evening; but there weren't many of them near the apparatus so I gassed myself *again* but this time it was by conscious choice), but the mixture didn't care one iota. I'm going to waste this one, chalk it up to,"you know there's no such thing as the easy way," and keep an eye out for povidone while I contemplate buying a bunch of KI. (Triflic: I'm finding chems to be more-and-more sparse on eBay and there's not much for local vendors so I'm resigning myself to the idea that it's easier if I just use onyxmet as my default supplier of dry chems).
Also, MidLifeChemist, you may have a point; I've read tons about precipitating Iodine this way, haven't seen much about actually *collecting* it this way, maybe the EtOH is the embuggerance and it's actually not a practicable route at all.
Thanks again for your input, folks.


unionised - 29-6-2021 at 04:09

I'd be tempted to add a reducing agent- steel wool, bisulphite- whatever- until the iodine was all reduced to iodide.
Evaporate off the water and alcohol.
Then dissolve the residue in a small volume of dilute HCl (or dilute H2SO4 or H3PO4) and then add the peroxide slowly.