Synthesizing Elemental Iodine from Iodine Tincture

[hydraliskdragon]

Since many chemical reactions use iodine, I was looking into making Iodine and stumbled across this thread http://www.scienceforums.net/forum/showthread.php?t=10886&highlight=Iodine.

 

Iodine tincture contains Iodide Ions which allow Iodine to dissolve readily in water. By passing though chlorine gas though the solution of tincture, we are able to oxidize the iodide back into iodine which is not very soluble in water.

 

Thus we end up with elemental iodine as a precipitate.

 

Here's a video of my synthesis.

http://www.youtube.com/watch?v=-_1-p4paM4U&feature=channel_page

 

PS. Iodine stains everthing

[hermanntrude]

just as a warning, anyone who wants to try this should be aware that chlorine gas is extremely dangerous. Do this in a fume hood, or preferably, not at all.

[YT2095]

it`s also worth a mention that Tincture is Alcohol based, and Alcohol and Cl2 could easily catch fire spontaneously just as it can with pure O2!

[Theophrastus]

Wait, upon heating and the like, how would the alcohol and chlorine (or any other halogen) interact?

[UC]

1) Wear gloves, kid.

 

2) Try generating chlorine via a method other than removing the stopper and splashing in some HCl as I'm sure plenty escaped that way. A pressure-equalizing addition funnel in a ground glass filtering flask with some FEP or PFA tubing leading into the solution would be ideal.

Edited May 25, 2009 by UC

[John Cuthber]

With poor control this becomes an experiment in the production of the chlorides of iodine.

http://en.wikipedia.org/wiki/Iodine_monochloride

[albgk]

There is another way (if your looking for one) to produce iodine.

you could use Potassium iodide (25g for $17.30 from Alfa Aesar) and use Muriatic acid (a big jug of it for $5 from a hardware store) and Hydrogen Peroxide (3% solution from drugstore) with a coffee filter and you have elemental iodine (look here for full process

) then you can purify it buy vaporizing it in a beaker with a ice water filled bell flask on top and the pure iodine will collect on the bell glass

 

 

i hope it helps

 

albgk

[Theophrastus]

I'm actually thinking of trying an experiment, quite similar to this. I plan to generate chlorine gas by mixing hydrogen peroxide, and hydrochloric acid, (in a consequently sealed glass flask) proceding to funnel the resulting chlorine gas, by means of clear PVC pipe, into the iodine tincture (which I would place in a glass erlenmeyer flask), where the iodine would then precipitate. Even though I like albgk's idea a bit better, I simply want to try this out to see how it works. To get a cleaner product, I plan to use C6H6 as a solvent, into which the iodine should dissolve, but the potassium iodide, potassium chloride, and ethyl alcohol would not. If all goes well the C6H6 layer, should quickly turn purple. Any thoughts upon the layout?

[Melvin]

It would probably be easier just to seperate out the iodides out and then oxidize them with HCl and peroxide; no need to set up a gas generator

 

Like YT said...mixing chlorine and alcohol (in the tincture) could be bad...

[ope]

i've done this... add excess hcl and then hydrogen peroxide, the alcohol doesn't react or anything as far as i saw no need to waste time seperating.

 

a lot of it will settle and you can just let it dry off... but it seems some always stays suspended and its like impossible to get it out (trying to filter it works horribly). if you evaporate it idk you'll have a lot of NaCl salt in the iodine.

 

one 2.0z bottle 2%tincture made a good small amount of iodine, i mixed it with aluminum flakes while still wet and it reacted great, started hissing and made a lot of purple smoke. (well, iodine vapor)

 

iodine is a cool element and this is a very safe experiment. both chlorine and iodine and hell iodine monochloride are pretty safe, i've inhaled vapors of all 3 they're pungent but not harmful.

 

theo that's a great idea, but look up first what's the solubility of iodine in benzene, both being nonpolar does not necessarily mean it will have super great miscibility.

Edited July 15, 2009 by ope

[John Cuthber]

Never trust anyone who tells you that WW(I) chemical warfare agents are not harmful.

"both chlorine and iodine and hell iodine monochloride are pretty safe, i've inhaled vapors of all 3 they're pungent but not harmful."

Particularly when it's only their 3rd post.

[Melvin]

both chlorine and iodine and hell iodine monochloride are pretty safe, i've inhaled vapors of all 3 they're pungent but not harmful.

 

All halogens and interhalogens are highly corrosive and can cause serious damage if you breathe them. You probably only inhaled a very small concentration...

[Theophrastus]

In regards to the benzene, I'm quite sure the solubility is sufficient, as my friend used it in an experiment to test for the presence of iodine ions in a solution, and he waas the one who gave me the idea, so I suppose its functional but not original.

 

I know many chlorinated organics are either known, or suspected carcinogens, but given the fickle amount of iodine within the solution, roughly 7%, I won't need very much chlorine, in the first place, and I'll be sure to keep the reaction contained.

 

In regards to the amounts of ethyl chloride, that will be generated, it shouldn't be of too much concern, as generally amounts around 1-3% should be fine. It's only when things grow more substantial than that, when things become a problem.

 

Still, liking the iodide idea better, it's only natural that I ask- is there any relatively simple means for obtaining potassium iodide, from iodine tincture?

Edited July 15, 2009 by Theophrastus

[Melvin]

Actually there is more sodium/potassium iodide in iodine tincture than there is iodine. I have a bottle in front of me now, and it is 2% iodine, 2.4% sodium iodide, 47% alcohol, and the rest is water. I suppose you could boil away the alcohol/water (although that would waste the 2% iodine) and you would be left with sodium iodide.

 

If you really were desperate, you could try getting some from iodized salt, although a normal size container (13oz or so) contains only about 2g of KI.

 

EDIT: You could also buy KI online, but it is far from cheap. I found 200g on eBay for US $9.50, but that was 99.99% pure. With more searching, you could probably find it cheaper.

[Theophrastus]

I know that potassium iodide is easy to buy on the internet, or from a chemistry supply store, but I don't really have the time currently to wait several weeks for it to come in. Boiling off the water and alcohol, I doubt is really safe, as the flash point of ethyl alcohol is 25 degrees celsius, so it is far more likely that the alcohol will burn, and in doing so, you may wind up with some nasty halogenated organic compounds. Basic probabilities taken into account, I'ld much rather bubble in chlorine.

[Melvin]

The flash point of ethanol is around 13C (from what I remember), but it's less than 50% ethanol in iodine tincture. However, if you keep all ignition sources away from it when it's boiling, you shouldn't have any problems. Hell, you could even just burn off the alcohol and leave everything else behind.

 

Also, keep in mind that chlorine is more reactive than iodine, so therefore it's more likely to halogenate the alcohol than iodine is.

[ope]

there's really no point boiling it, some alcohols will react with chlorine or HCl at room temp. but ethanol would have to burn, the same as it does to react with oxygen in air. i mean its nice theo that you are trying to do everything 100% perfect but i'm surprised you're not bored of it already.

 

btw hydradragon i just saw the video it looks awesome! just so you know the hcl + naocl or whatever you used you could have just poured iodine tincture directly in there instead of creating a tube for the chlorine to bubble through. in that case, add hcl and tincture before adding naocl (replaceable by h2o2).

 

oh and if you use the h2o2 + hcl you don't have to worry about chlorine either since then its 2 seperate reactions:

HCl + NaI > HI + NaCl

2HI + H2O2 > H2O + I2

 

and as for breathing iodine or chlorine or whatever its not because its a low concentration its because any fuсking idiot would know that when something smells extremely irritating, not to go ahead and directly inhale it! if its spewing out, big deal stand a couple feet back.

Edited July 15, 2009 by ope

[UC]

Theo- Heptane is a very good solvent for iodine and less nasty than benzene. You'll find that the volatility of iodine makes separation nearly impossible though. You're better off slowly adding a sulfite solution to the tincture just until it goes clear, neutralizing with NaHCO3 solution (since the reduction generates HI), boiling off the alcohol, and then oxidizing the iodide back to iodine with chlorine generated in-situ. This part is actually what ope was trying to suggest above, but I've removed ethanol from the equation. Acidify the liquid with HCl and use a dropper to add bleach with swirling until you don't get any further precipitate.

Edited July 17, 2009 by Pangloss
ope stuff removed, please pardon the edit