Sciencemadness Discussion Board

Povidone Iodine

sternman318 - 13-7-2011 at 13:27

Yes, I tried to use the search function but I had a hard time getting clear, useful answers- and I was tired of reading poorly written out procedures by meth cookers. So-

Povidone-Iodine solution releases " free iodine" .
Does this mean I2 is released? And I assume this is an equilibrium?

Despite there apparently being "free iodine", I assume heating it and condensing the sublimated iodine wont work as I think everyone would be doing that.

A post by Nicodem says that it exists not as I2, but as I3-. I3- also forms an equilibrium in water of
I 3- <-> I2 + I-

Thus, could I just not oxidize the I- by the acid and hydrogen peroxide method? Purify by sumblimation and recrystallization?

My other question is the label lists it as a 10% solution of Povidone-Iodine( 1% available iodine). I never understood the whole % thing( give me molarity and I am golden xD), but I assume it means 10% by mass? How would I calculate the iodine content? The polymeric nature of it makes it a little more complicated aswell.

[Edited on 13-7-2011 by sternman318]

Bot0nist - 13-7-2011 at 14:58

<a href="http://www.youtube.com/watch?v=VeQ_BDWm7ls">Check out this video.</a>. It's a good procedure that has worked for me many times.

Heating the liquid won't yield many crystals due to all the evaporating water/alcohol, and the fact that most povidone solutions usually contains a polymer, from which you will need to free up the iodine.

I think the channel is from one of our members.

[Edited on 13-7-2011 by Bot0nist]

#maverick# - 13-7-2011 at 15:22

You can use h2so4 and h2O2 to oxidize the iodine to i2. Check out my site I have a procedure it uses KI but you can just replace the KI with povidine and it still work. If u want an even purer product you can then sublimate it

MrHomeScientist - 14-7-2011 at 06:10

Quote: Originally posted by Bot0nist  
<a href="http://www.youtube.com/watch?v=VeQ_BDWm7ls">Check out this video.</a>. It's a good procedure that has worked for me many times.

Heating the liquid won't yield many crystals due to all the evaporating water/alcohol, and the fact that most povidone solutions usually contains a polymer, from which you will need to free up the iodine.

I think the channel is from one of our members.

[Edited on 13-7-2011 by Bot0nist]


I've done the procedure in that video, but made a critical mistake that was actually one of the more alarming experiences I've had! Instead of using 3% H<sub>2</sub>O<sub>2</sub>, I figured I'd use 30% instead since that would require less volume.
Turns out that's not a good idea.

Upon adding it, the solution rapidly heated up to scalding hot and began spewing large clouds of iodine vapor out of the beaker. I had to run it outside, spewing purple fumes throughout my house the whole way. Luckily, nothing was stained too badly and I avoided breathing in much of it, so nothing really bad came of it. It was still pretty scary, especially as it was indoors. So moral of the story: higher concentration isn't always better!

Hexagon - 14-7-2011 at 13:44

Believe me I've tried every single method under the sun that I could think off, overoxidizing, match book RP, precipitating the complex by adding salt, reducing the iodine even with honey and carbonate, adding alkalies, copper powder, etc, etc. I did not tried that method of the video because I find it wasteful to boil all that water to such low ammounts of iodine. I can say that working under alkaline conditions makes it more complicated because even carbonate fucks up the polymer.

Now comes that one saying, you can get iodides or iodine over the net blao blao blao, yeah in my country there is not problem with iodine so I can get tons of it NQA, so I do it just for fun.

Well, in fact I think that the tipical 1% solution does not contain a 1% of total iodine, I think that it contains a 1,5% of total iodine, being 1% trapped I2 and the rest, mostly iodide and some iodate.

So the method I finaly worked out (for the isolation of the iodides) was adding to the Pov-I2 solution some aluminum foil and then adding slowly (I mean, with a Syringe some mililiters at a time, wait some minutes, then again, etc) with stirring a solution of CuSO4 + NaCl. You can work the stequiometry your self. If added sloyly one obtains a precipitate of Copper (I) iodide, witch by the way is unsoluble in water, and can be filtered.

There I got, bored of it after isolating the copper iodide salt so I did not finish my method :) May be I'll make a video or something one day.

Have a nice day.