Sciencemadness Discussion Board

iodate to iodine!

TheySHoutOutHempy - 12-1-2012 at 23:45

Hi, new here.

I've been trying to produce some iodine solid for a while, because here in aus you cannot buy it outright. I can't even get a hold of any KI for less than a huge amount of money. I can, however, get my hands on copious amounts of KCIO3 (Potassium iodate) which is mixed in with NaCl. I would like to know if there is any possible way of isolating the iodate, then converting it to iodine?

thanks in advance.

ScienceSquirrel - 13-1-2012 at 04:27

What proportion of potassium iodate is there in the mixture?

AJKOER - 13-1-2012 at 05:26

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]

TheySHoutOutHempy - 13-1-2012 at 05:48

Quote: Originally posted by ScienceSquirrel  
What proportion of potassium iodate is there in the mixture?


annoying because I have no idea. I bought this 1kg bag of salt, and it only lists ingredients in order, not in any proportions.

by the way, I found one process, follows

"An alternative protocol uses a solution of iodate ion (for instance potassium iodate) to which an acidified solution (again with sulfuric acid) of sodium bisulfite is added.
In this protocol, iodide ion is generated by the following slow reaction between the iodate and bisulfite:
IO3− (aq) + 3HSO3− (aq) → I− (aq) + 3HSO4−(aq)
This is the rate determining step. The iodate in excess will oxidize the iodide generated above to form iodine:
IO3− (aq) + 5I− (aq) + 6H+ (aq) → 3I2 + 3H2O (l)
However, the iodine is reduced immediately back to iodide by the bisulfite:
I2 (aq) + HSO3− (aq) + H2O (l) → 2I− (aq) + HSO4−(aq) + 2H+ (aq)
When the bisulfite is fully consumed, the iodine will survive (i.e., no reduction by the bisulfite) to form the dark blue complex with starch."

source: http://en.wikipedia.org/wiki/Iodine_clock_reaction

this will be my next experiment, as soon as I find some acid and NaHSO3. Do you think I could substitute H2SO4 for HCl or acetic acid even? I mean, it only need's the H+

ScienceSquirrel - 13-1-2012 at 06:01

The potassium iodate is added to the salt as an iodine supplement in very small amounts. I doubt it is a useable source of iodine.
Can you get tincture of iodine?
This would be a practical source.

neptunium - 13-1-2012 at 08:27

povodone iodine is availlable everywhere at an affordable price and is not being watch in anyway...

LanthanumK - 13-1-2012 at 10:17

Tincture of iodine is one of the best sources of iodine.

Just today I extracted iodine crystals by adding a small amount of NaClO bleach to a slightly acidified dilute solution of tincture of iodine. Too much bleach seems to make either the monochloride in acid solution or the iodate (?) in alkaline solution. Bleach alone makes the solution alkaline.

Iodine monochloride in HCl solution when neutralized by NaHCO3 (destroying the HCl) indeed precipitates iodine crystals.

MrHomeScientist - 13-1-2012 at 13:57

Iodine is only added to table salt in trace amounts, so you really won't be able to get anything of value out of it. Tincture of iodine or povidone iodine, as mentioned, are both good sources that area easy to get elemental iodine from.

If you're trying out the iodine clock reaction, that's not a very practical source for elemental iodine either (if that's what your after that is - the reaction itself is incredibly cool on its own). When the 'clock' stops, you're left with the iodine in a complex with starch, so you'd have to remove it. In my experience, this can be done with heating to produce iodine vapor, which you could then condense on a cold surface into I2 crystals. I say it's not very practical, though, because of the large amounts of other chemicals you need to run the clock reaction.

The simplest method would be to acidify potassium iodide solution with sulfuric acid, if you can find any that is.

ScienceSquirrel - 13-1-2012 at 14:26

Try your local pharmacist / chemist for tincture of iodine.
After that I would try outdoor / camping shops, shops that sell to small holders and then home brew shops. Beer brewers use it to test for starch conversion.
Home chemists need to be ingenious!

TheySHoutOutHempy - 13-1-2012 at 15:59

OP here. Tincture extraction is too costly for my purposes, I'm on a tight budget (uni student). The bag of NaCl/KIO3 was extremely cheap, so maybe if I use huge quantities, I could make a few grams? That's all I need. I read somewhere that iodized salts can contain from 100 mg/ 1kg up to 3000 mg per 100 grams. I don't know the source of these, I'm sorry. I wish I had 'borrowed' some apparatus before I left school, then maybe I could have performed the heating and then condensation. What would be the filtrate of filtering the clock solution through filter paper?

ScienceSquirrel - 13-1-2012 at 16:13

Quote: Originally posted by TheySHoutOutHempy  
OP here. Tincture extraction is too costly for my purposes, I'm on a tight budget (uni student). The bag of NaCl/KIO3 was extremely cheap, so maybe if I use huge quantities, I could make a few grams? That's all I need. I read somewhere that iodized salts can contain from 100 mg/ 1kg up to 3000 mg per 100 grams. I don't know the source of these, I'm sorry. I wish I had 'borrowed' some apparatus before I left school, then maybe I could have performed the heating and then condensation. What would be the filtrate of filtering the clock solution through filter paper?


Save yourself some money.
Go for a walk on the sea shore, pick up loads of kelp, dry and burn it to ash, extract and process.
More iodine per kilo than the crap you are dealing with!

TheySHoutOutHempy - 13-1-2012 at 16:16

Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by TheySHoutOutHempy  
OP here. Tincture extraction is too costly for my purposes, I'm on a tight budget (uni student). The bag of NaCl/KIO3 was extremely cheap, so maybe if I use huge quantities, I could make a few grams? That's all I need. I read somewhere that iodized salts can contain from 100 mg/ 1kg up to 3000 mg per 100 grams. I don't know the source of these, I'm sorry. I wish I had 'borrowed' some apparatus before I left school, then maybe I could have performed the heating and then condensation. What would be the filtrate of filtering the clock solution through filter paper?



Save yourself some money.
Go for a walk on the sea shore, pick up loads of kelp, dry and burn it to ash, extract and process.
More iodine per kilo than the crap you are dealing with!



...proceed. tell me more. I honestly thought it would be easier to obtain iodine than burning seaweed and extracting it, but beggars can't be choosers.


[Edited on 14-1-2012 by TheySHoutOutHempy]

AJKOER - 13-1-2012 at 16:59

Per Lanthanumk reactions:

NaOCl + H(+) --> HOCl + Na(+)

I2 + 2 HOCl --> Cl2 (g) + 2 HOI

5 HOI --> 2 H2O + 2 I2 (s) + HIO3

where I am assuming the solution has been neutralized to facilitate the Iodine precipitation.

So per my analyst, 80% of the available Iodine is recovered with 20% in the form of an Iodate remaining behind.

However, adding more dilute acid and excess NaI, for example, then:

(dilute acid reaction equation)

5 NaI + NaIO3 + 6 H(+) --> 6 Na(+) + 3 I2 (s) + 3 H2O

and theoretically all the iodine may be subject to recovery.






ScienceSquirrel - 13-1-2012 at 17:26

Quote: Originally posted by TheySHoutOutHempy  
Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by TheySHoutOutHempy  
OP here. Tincture extraction is too costly for my purposes, I'm on a tight budget (uni student). The bag of NaCl/KIO3 was extremely cheap, so maybe if I use huge quantities, I could make a few grams? That's all I need. I read somewhere that iodized salts can contain from 100 mg/ 1kg up to 3000 mg per 100 grams. I don't know the source of these, I'm sorry. I wish I had 'borrowed' some apparatus before I left school, then maybe I could have performed the heating and then condensation. What would be the filtrate of filtering the clock solution through filter paper?



Save yourself some money.
Go for a walk on the sea shore, pick up loads of kelp, dry and burn it to ash, extract and process.
More iodine per kilo than the crap you are dealing with!



...proceed. tell me more. I honestly thought it would be easier to obtain iodine than burning seaweed and extracting it, but beggars can't be choosers.


[Edited on 14-1-2012 by TheySHoutOutHempy]


Tincture of iodine or similar contains a few grams of the element per 100ml. It is easy to extract and purify.
If you cannot buy iodine or potassium iodide I think it is the best thing to start from.
Iodised salt, kelp ashes, etc are way down the list of prefered starting materials to my mind.

TheySHoutOutHempy - 13-1-2012 at 18:26

Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by TheySHoutOutHempy  
Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by TheySHoutOutHempy  
OP here. Tincture extraction is too costly for my purposes, I'm on a tight budget (uni student). The bag of NaCl/KIO3 was extremely cheap, so maybe if I use huge quantities, I could make a few grams? That's all I need. I read somewhere that iodized salts can contain from 100 mg/ 1kg up to 3000 mg per 100 grams. I don't know the source of these, I'm sorry. I wish I had 'borrowed' some apparatus before I left school, then maybe I could have performed the heating and then condensation. What would be the filtrate of filtering the clock solution through filter paper?



Save yourself some money.
Go for a walk on the sea shore, pick up loads of kelp, dry and burn it to ash, extract and process.
More iodine per kilo than the crap you are dealing with!



...proceed. tell me more. I honestly thought it would be easier to obtain iodine than burning seaweed and extracting it, but beggars can't be choosers.


[Edited on 14-1-2012 by TheySHoutOutHempy]


Tincture of iodine or similar contains a few grams of the element per 100ml. It is easy to extract and purify.
If you cannot buy iodine or potassium iodide I think it is the best thing to start from.
Iodised salt, kelp ashes, etc are way down the list of prefered starting materials to my mind.


I know it's all over the internet, but extracting it from tincture: HCl, H2O2 in 1:2 ratio amount, am I right? Just one question..can the H2O2 be in the form of drain cleaner or some commercial product? I.e. can it have huge impurities.

Bot0nist - 13-1-2012 at 18:45

Drain cleaner made of hydrogen peroxide? I doubt it. Since its all over the internet, why not UTFSE. Even YouTube has tons of video on this, not to mention a dozen threads about getting iodine from OTC topical solutions.