I have been trying to make me some elemental iodine for future experiments.
Now iodine has thanks to the damn methheads become really hard to come by.
We still has iodine tinctures so i thought i try to get some iodine out of that before they too are taken off market.
Now to my problem,
I put 100ml of 5% iodine tincture in a beaker, added 50ml of 30% HCL slowly while stirring.
Some small fuming appeared.
I then added 100ml of 3% H2O2 slowly with stirring.
Now after a few minutes one should have iodine crystals precipitating in the solution but i don't.
Actually nothing at all happens.
After letting it stand for a while 2 layers are formed, one upper layer who is clear with yellow color and a lower layer who is dark red almost black.
Why doesn't the iodine crystals fall out?
Can it be that my iodine tincture has some tensides in it also and they are interfering with the reaction?

I know we have some chemistry wizards here, maybe someone can explain to me why this wont work.

Grower

Nobody can help with this?
I must try figure out what exactly is happening chemically when acidifying and then when adding the peroxide.

I made 2 try with this, the first one i diluted the iodine tincture with some distilled water and the other without water but the results are the same.
The Erlenmeyer flask has now formed 2 distinct layers where the upper biggest layer is clear or slightly yellow/orange and the bottom layer is deep dark red.
However there is no iodine precipitating at all.
I have followed the procedure to the letter and even watched some youtube videos where it is done but i don't get the correct/same results.

Anybody has some ides what can be going wrong OR anybody can explain how things should happen chemically?
There must be some members with chemical knowledge/skills here.

Grower

Hmm, this procedure is new to me. I'm guessing its intent is to take a iodine/iodide mixture, turn the iodide to hydriodic acid, react that with H2O2, yielding just iodine. Efficient.
Your iodine is clearly still soluble in the solvent system, iodides and hydriodic acid makes iodine soluble in water. Add more H2O2, or HCl perhaps? Once all the iodine is elemental iodine only a quarter of a gram should dissolve in a liter of cool water.

A modification to the procedure could be done. Iodine sublimes.
Iodine tincture could be evaporated at room temp and placed in something like a half pint jar, then another half pint jar placed inverted over the top to make a closed vessel. The bottom one is gently heated while there is a bit of air current to cool the top one. Iodine crystals should grow in the top jar after some time and at the end the potassium iodide left in the bottom one could still be reacted as per your hydrogen peroxide tek to convert it to iodine. Do not breathe the vapors.
Probably only worth the bother if your tek is problematic or inefficient.

I have been thinking that adding more H2O2 might convert the liquid iodine (Hydriodic acid?) to elemental form witch i should be able to filter out of the solution.
So adding HCL to the 5% iodine tincture converts the iodine to hydriodic acid?
If i somehow could separate out the iodine content from the tincture so i get rid of the other stuff present (tensides as in washing powder) i could do a variant of what you wrote and heat it in a beaker with a ice water filled round bottom flask put on top of the beaker.
The iodine should vaporize and when hitting the cold bottom of the RBF it should deposit there at high purity.

What has happen now is that i got 2 layers, one clear/yellow top layer witch must be water/acid and all tensides and junk and one clear, dark red bottom layer witch must be the iodine in some form, probably hydriodic acid then.
I will separate the deep red layer in my sep. funnel and try adding 3% H2O2 to see if any iodine precipitates out.

Thanks for helping me and giving me some info how this procedure works.

Grower

Hmm...
I have now put a small amount of the deep red layer i a beaker and added an large amount of H2O2.
No iodine precipitates...
The deep red solution just bubbles from the H2O2 like a coca cola.
That means the deep red isn't hydriodic acid or?

Im so confused why this simple reaction dont work.
Can it be the tensides in the iodine tincture that make things wierd?
I must see if i can get a complete spec of the iodine tincture.
It says 5% iodine + tensides on the bottle.

Grower

This question is better off in the advanced/enhanced chemistry section of the forum. So as long as ya stick around here for a bit and post decent posts you will soon be able to post in that section. I would re-ask this question you have that availability.

That is probably a good idea.
I post it there, i think i can post there.

Tnx.
Grower