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Author: Subject: Povidone iodine question
Slovo
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[*] posted on 3-5-2015 at 12:01
Povidone iodine question


My question is what are the reactions that are happening when povidone iodine reacts with KOH then,products react with HCL and finally products of that reaction with H2O2.
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Milan
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[*] posted on 3-5-2015 at 12:25


In povidone iodine I think only iodine should be reactive towards KOH.
Here's an extract from wikipedia:
"It can also be prepared by adding iodine to a hot, concentrated solution of potassium hydroxide.

3 I2 + 6 KOH → KIO3 + 5 KI + 3 H2O"

Also I found this thread: http://www.sciencemadness.org/talk/post.php?action=reply&...

Quote: Originally posted by AJKOER  
On the reduction:

Low Acid Concentration:

5 KI + KIO3 + 6 HCl --> 6 KCl + 3 I2 + 3 H2O

But in high acid concentration:

2 KI + KIO3 + 6 HCl --> 3 KCl + 3 ICl + 3 H2O

and ICl + H2O --> HOI + HCl

But immediately:

5 HOI --> 2 H2O + 2 I2 + HIO3

Source, per my notes, is Mellor, around page 118.

I suspect your source of KIO3 actually already has some KI. My speculation is based on:

3 I2 + 3 H2O <-----> 5 HI + HIO3

and upon adding KOH, produces KI and KIO3. Potassium iodate is reportedly prepared by the anodic oxidation of a KI solution. My attempt at this:

KI + H2O <---> KOH + HI

4 HI + O2 --> 2 H2O + 2 I2

and again we have Iodine and water plus KOH.

---------------------------------------------------------------

Working with solid KIO3, one could attempt a thermal decomposition (between 655 to 736 K):

KIO3 --> KI + 3/2 O2

Also, a reported secondary reaction:

4 KIO3 --> 2 K2O + 2 I2 + 5 O2

so be prepared to condensed escaping Iodine.

Source: "High temperature properties and thermal decomposition of inorganic salts ..." by Kurt H. Stern, page 248.

Link:

http://books.google.com/books?id=2BpMo7HpXzIC&pg=PA248&a...

Then, treat the Potassium iodide with Chlorine:

2 KI + Cl2 --> KCl + I2

or, one could theoretically use the KI to seed the first procedure that requires some KI.

Let me know what happens.


[Edited on 13-1-2012 by AJKOER]


As for H2O2 there's this thread about interaction between H2O2 and I2: http://www.sciencemadness.org/talk/viewthread.php?tid=18302

As for KCl I found this webpage: http://chemistry.stackexchange.com/questions/6032/potassium-...
It says the KCl would be oxidised to chlorine gas?(though I'm not sure about this).
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