Sciencemadness Discussion Board

Iodine from iodised salt?

Ramium - 27-12-2014 at 22:31

I have been wondering if it is possible to extract elemental iodine from iodised table salt . Does anyone know how?

j_sum1 - 27-12-2014 at 22:41

I would guess that the quantities involved are extremely small. If I was to attempt it I would bubble Cl2 gas through a brine solution.
But why? You would have much more success extracting from Betadiene. (1%available iodine.) I am not sure that there is any other OTC product that has higher iodine content.

Ramium - 27-12-2014 at 23:30

How do you extract iodine from betadiene
(And where do you get betadiene)

Ramium - 27-12-2014 at 23:46

Is it possible to do it with no dangerous easy to obtain chemicals
(I am new to chemistry)

j_sum1 - 28-12-2014 at 00:38

Betadene is a topical antiseptic otherwise known as povidine iodine. There is a good wikipedia article on it. It is the brown stuff that surgeons paint on the skin before surgery. It is very widely available. I believe it is the most concentrated otc source of iodine but I may be mistaken. In any case it would be expensive to produce iodine this way. Much cheaper to buy.

I intend to extract I2 from betadene this week. Sulfuric acid would be easiest bit I will use HCl and an oxidant.

blogfast25 - 28-12-2014 at 07:18

More fun: from kelp! Dry kelp, burn it, leach ashes with warm water, evaporate lixiviate to dryness, convert iodides to iodine as per usual.

Ramium - 28-12-2014 at 11:54

Could you describe your kelp method in more detail please

dermolotov - 28-12-2014 at 13:47

Quote: Originally posted by j_sum1  
I would guess that the quantities involved are extremely small. If I was to attempt it I would bubble Cl2 gas through a brine solution.
But why?

Get a tincture of iodine instead. Evaporate the alcohol and perform the bubbling mentioned. Then sublimate using a tall form beaker covered with a RBF with ice in it. Scrape off the pure elemental iodine and place in an ampoule.

Tinctures of iodine around around $4 for 25cc. Gram for gram, it's cheaper, easier, quicker, and overall better to extract iodine out of this than table salt.

WChase501 - 28-12-2014 at 15:24

I would agree with the iodine tincture. More cost effective and easier.

Ramium - 28-12-2014 at 21:01

Where do you get iodine tincture and could you please discribe the extraction in more detail

dermolotov - 28-12-2014 at 21:41

Quote: Originally posted by Ramium  
Where do you get iodine tincture and could you please discribe the extraction in more detail

I buy these for $5 bucks a shot in my local "Shopper's Drug Mart" in Canada:

http://www1.shoppersdrugmart.ca/en/health-and-pharmacy/every...

j_sum1 - 28-12-2014 at 22:27

From a pharmacist or first aid supplier. It is a mixture of iodine and potassium iodide in water and ethanol. I have not seen it for a long time. Betadine (spelling correct this time) is pretty much universal around here.

Extraction should be straightforward. This is a simple redox reaction. I- is oxidised to elemental iodine.
2I- ==> I2 + 2e-
So you need an oxidiser. Something to use up those electrons. I am going to use acidified potassium chlorate because that's what I have available.
ClO3- + 6H+ + 6e- ==> Cl- +3H2O
(The potassium ions and the anion for the acid are just spectator ions so I have not shown these.)

Other possible oxidisers are sulfuric acid, hydrogen peroxide, chlorine gas or pool chemicals. You could use acidified potassium permanganate but I won't recommend it since its deep purple colour will disguise the iodine you make. Also, if you use HCl (as I am) you will create some Cl2 gas which you want to be prepared for. Like I said, sulfuric acid is your best option.

Simply add a few drops of concentrated H2SO4 to your iodine tincture in a test tube and you should see the brown colour disappear and be replaced by dark crystals that will settle out. Filter your mixture and rinse with water. Put the crystals in the bottom of a beaker and cover with a bowl or round flask filled with ice. Heat the beaker gently. Your iodine should sublime and recrystallise on the bowl. You can then scrape off your purified crystals.
After a small practice run, increase the quantity if you like.

The same method applies if you are using potassium iodide, Betadine iodised salt or kelp extract. Yields will be different though since some of these are more concentrated sources than others.

j_sum1 - 28-12-2014 at 22:30

You may be able to buy iodine "water purification tablets" from a camping store. These would work as well.

Ramium - 28-12-2014 at 23:35

Where do you get iodine tincture and could you please discribe the extraction in more detail

j_sum1 - 29-12-2014 at 00:27

Quote: Originally posted by Ramium  
Where do you get iodine tincture and could you please discribe the extraction in more detail

I thought I just did!

blogfast25 - 29-12-2014 at 11:28

Quote: Originally posted by Ramium  
Could you describe your kelp method in more detail please


There are instructables on the net.

Basically quite a lot (a few kg) of kelp is harvested and laid out to dry. It is then burnt inside of a steel bucket or such like and the ashes gathered. These contain small amounts of KI. Leach out the KI from the ashes with hot water, filter off the water insolubles.

Boil in the filtrate to near dryness. Adding hydrogen peroxide (or other oxidisers) oxidises the iodide to free iodine.

[Edited on 29-12-2014 by blogfast25]

dermolotov - 29-12-2014 at 11:35

Quote: Originally posted by j_sum1  

I thought I just did!

lmao.

And I thought I just described where to get it!!


@J_sum1
Ever considered the possibility of bubbling in Chlorine? IMO, that might actually be easier and cheaper albeit a tad more dangerous.

[Edited on 29-12-2014 by dermolotov]

blogfast25 - 29-12-2014 at 11:40

Quote: Originally posted by dermolotov  
@J_sum1
Ever considered the possibility of bubbling in Chlorine? IMO, that might actually be easier and cheaper albeit a tad more dangerous.

[Edited on 29-12-2014 by dermolotov]


You'll form also ICl.

dermolotov - 29-12-2014 at 11:52

Quote: Originally posted by blogfast25  

You'll form also ICl.

Didn't know the simple existence of that. Cheers Blogfast.
So ends the uselessness of formal lab experience. It's a shame they don't work with Chlorine gas in labs anymore...

If Chlorine gas fails to liberate iodine, I guess one could still use Chlorine. Add HCl to make Hydroiodic acid and do a simple oxidation with chlorate mentioned above. I think this would capture the free iodine as well as the potassium iodine in the tincture.

Otherwise, buy 4 of those 25cc jugs, put them all in a 400cc Beaker, put a 500cc RBF filled with ice on top of it, and sublimate the iodine out. Then distil off the ethanol and work with the Potassium Iodide that was proposed earlier.

Ramium - 29-12-2014 at 12:20

I am new to chemistry i dont know what the bubbling method is.that is what i ment when i asked for a more detailed description

blogfast25 - 29-12-2014 at 12:47

Quote: Originally posted by dermolotov  
If Chlorine gas fails to liberate iodine, [...]


I didn't say that. Cl2 will oxidise iodide to iodine but ICl is a likely by-product. Inter-halogens are common: Cl2 also oxidises bromides but BrCl is also a by-product.

And of course they still work with chlorine in laboratories.

[Edited on 29-12-2014 by blogfast25]

Ramium - 29-12-2014 at 13:06

I think i will try the kelp method .can you tell me the equations for KI H2O2 reaction

S.C. Wack - 29-12-2014 at 15:54

I suspect that everything about iodine has been covered in other threads, and that the various reactions of iodide and peroxide exist in video form.

gdflp - 29-12-2014 at 16:36

For everyone who is interested in the kelp method : Google Results

Ramium - 29-12-2014 at 20:20

I just got some iodine tincture i plan to extract the iodine by boiling it down to get rid of most of the ethanol and water then adding H2O2 to convert the iodide to iodine
Do you think this would work

diddi - 29-12-2014 at 21:25

is there any lit on preferentially crystallising the alpha form of ICl over the beta form? might be a nice little project

[Edited on 30-12-2014 by diddi]

j_sum1 - 29-12-2014 at 21:41

@Ramium
I wouldn't boil it down first. The tincture has iodine in the form of the tri-iodide ion. You can think of it as a iodide ion I- combined with an I2 molecule. If you heat you could drive off the I2 as a vapour and your yield will be lower. On the other hand, if you oxidise you will have I2 precipitate since it is insoluble in water. This separates easily.

Ramium - 30-12-2014 at 16:41

Thanks for the advice.i did some internet surfing and found a differnt recipe using
HCL and H2O2 .this is the recipe

4 parts 2% iodine tincture to one part DH2O (distilled water)
You will also need .75 ml 30% HCL per fluid ounce of iodine tincture. You will need a container to hold all of the fluids you now have in front of you. It doesn't matter if its a bowl, jar, beaker, or anything else. Just make sure to always use glassware.

You start out by pouring the iodine tincture into the container. Slowly add the DH2O and stir, but always avoid splashing. Then, slowly add the HCL and stir.

At this point, you need to wait for about 15 minutes to let the reagents do their work. --- After you have waited 15 minutes, add the H2O2 slowly while stirring. At this point, you need to wait for 12 hours. --- Now, you need to have a filter and another container ready. I recommend an ultra fine plastic mesh cone filter. It won't clog, and it won't absorb any of the liquid. Sometime the color will be too dark, and you can add a bit more H2O2 and let it sit for a second pull. Now you need to rinse the crystals that remain in the filter with copious amounts of water. After this, spoon or tap them onto a stack of three coffee filters. Fold the filters so nothing can come out. Now take some paper towels and wrap them around the filter and try to get as much of the moisture out as you can. The final step is to drop the still closed filter into a container with Damp-Rid or any kind of moisture absorbing product. If you chose to add more H2O2, proceed in the same fashion for the second pull. Would this work? Sorry to keep asking.

[Edited on 31-12-2014 by Ramium]

gardul - 3-1-2015 at 02:52

maybe I am missing something here. But wouldn't it just be easier to use postassium Iodide as the source of idoine.

morganbw - 3-1-2015 at 04:08

Quote: Originally posted by gardul  
maybe I am missing something here. But wouldn't it just be easier to use postassium Iodide as the source of idoine.


People often like to take different routes to the same item, but, yes, I think so.

CuReUS - 7-1-2015 at 00:10

in nurd rage's video ,he adds sulphuric acid to KI solution to get Iodine
https://www.youtube.com/watch?v=2F_kPXbi2D8

but it never works whenever I do that(I never used an ice bath though,do you think that's important?) ,can someone tell why ?
so instead of adding sulphuric acid,I used to add conc nitric acid,and the colorless KI solution would instantly turn black,which made me believe that I was getting iodine

but recently I learnt that nitric acid oxidizes iodine to iodic acid(HIO3) :(
http://en.wikipedia.org/wiki/Iodic_acid

[Edited on 7-1-2015 by CuReUS]

Sniffity - 7-1-2015 at 09:43

It should be possible, but rather impractical to obtain the iodine.

However, to explore the science behind it..

Upon dissolving table salt, you should get a solution of Sodium Chloride and Potassium Iodide. If you were to bubble Chlorine gas through said solution, the Chlorine would displace the iodide, forming Potassium Chloride. The Iodide would convert to Iodine, which should precipitate out.

gardul - 7-1-2015 at 17:03

I have always used the HCl and H2O2 method.

basically desolve KI in small amount of water and add equal amounts of HCl. Add three times as much Hydrogen Peroxide (3%) Stir. and let it sit for 10 to 15 minutes. Filter out the iodine let it dry.

While this may be a boring way I have found it rather affective since iodine is so restrictive here.

morganbw - 8-1-2015 at 05:23

Quote: Originally posted by CuReUS  
in nurd rage's video ,he adds sulphuric acid to KI solution to get Iodine
https://www.youtube.com/watch?v=2F_kPXbi2D8

but it never works whenever I do that(I never used an ice bath though,do you think that's important?) ,can someone tell why ?
so instead of adding sulphuric acid,I used to add conc nitric acid,and the colorless KI solution would instantly turn black,which made me believe that I was getting iodine

but recently I learnt that nitric acid oxidizes iodine to iodic acid(HIO3) :(
http://en.wikipedia.org/wiki/Iodic_acid

[Edited on 7-1-2015 by CuReUS]


Refer to Woelen's first reply in this thread. It is pretty nice.
Subject: Synthesis of Iodine from KI and sulfuric acid question.


[Edited on 8-1-2015 by morganbw]

CuReUS - 8-1-2015 at 08:36

morganbw
but I used 98% sulphuric acid on the KI solution . maybe my KI was not contaminated with KIO3 :)

Woelens method

morganbw - 8-1-2015 at 09:18
Quote:

Indeed, 30% acid does not oxidize iodide to iodine. Using conc. H2SO4 for oxidizing iodide to iodine also is a bad idea, because that reaction is extremely messy and dirty. If you add conc. H2SO4 to solid KI, then you get a mix of HI, H2S, S8, I2 and SO2. This mix is extremely smelly and looks dirty brown with yellow specks like bad shit. Isolating the iodine from this dirty 'shit' is not a pleasure at all.

A much better method is to dissolve the KI in 30% H2SO4 and then add dilute H2O2 to this. Try to add a slight excess of H2O2 and do this slowly while stirring. At a certain point you will see lots of glittering particles of iodine forming in the dark liquid. If you wait long enough, then you see that the liquid turns lighter and iodine settles at the bottom and another part of the iodine settles near the surface. You can pour the iodine on a filter (preferrably use a sintered glass filter and if that is not available, then use a dense paper filter). The wet iodine then can be put in a small beaker to which about three times its own volume of concentrated sulphuric acid is added. When this beaker is heated, then you can see the iodine melting, forming a nearly black liquid, which remains under the sulphuric acid layer. After this step and solidifying of the iodine, you can decant the acid liquid (which contains water and left over potassium ions and a small amount of iodine) and add another small portion of conc. H2SO4. Heating again makes the iodine really clean. After cooling down you can decant the acid again and then rinse with a lot of water. Finally, you end up with a piece of iodine, which you can wipe dry with a small paper tissue and then break down in parts with a glass rod. You can also keep it as one piece. The iodine, produced in this way is pure enough for all practical home chemistry experiments and syntheses.

If you want the iodine really pure, then you can heat it and let it sublime on a piece of cold glass. I myself tried this, but I had limited succes, I stopped the process, because I lost a lot of purple vapor.


The most tricky part of the process described above is the filtering step. You end up with a dark grey mud, which stains everything. Paper becomes black, skin becomes yellow/brown (like you sometimes see with certain tobacco users) and clothes become brown. That's why the best results are obtained with a sintered glass filter, from which you can easily scrape the mud. The filter itself is cleaned very easily by rinsing it with a dilute solution of sodium sulfite or bisulfite.



I was wanting you to see the process he used. It seems to be the best I have come across. Nothing about KClO3 in his first response, just the method he uses.

[Edited on 8-1-2015 by morganbw]

Yugen - 8-1-2015 at 12:37

Quote: Originally posted by Ramium  
Could you describe your kelp method in more detail please


I once thought this was a good idea too, until I really looked into it. Check out this old textbook that explains how iodine was made back in "the good ole' days" :)

http://babel.hathitrust.org/cgi/pt?id=uc2.ark:/13960/t3tt4gz...

CuReUS - 8-1-2015 at 23:30

Quote: Originally posted by morganbw  

I was wanting you to see the process he used. It seems to be the best I have come across. Nothing about KClO3 in his first response, just the method he uses.

I saw that too. he says that it becomes a mess.But when I added the sulphuric acid,NOTHING happens.
no fumes,no black goo,no iodine ppt nothing :mad:
but when I put nitric acid,the solution immediately turns black,but there are no fumes

Ramium - 19-1-2015 at 16:13

Its working!!!! I can see iodine crystals forming lots of them to
Yes! Yes! Yes! Yes! Yes! Yay!!!!!!!!!!!!!!!!!

jhonthebaptist - 29-1-2015 at 08:35

I made some I2 before with ammonium iodide tincture from the store. After I dried it, it was was about the size of a pea. I accidentally dropped it on the floor and it exploded, more like a purple fire cracker. Nitrogen tri-iodide was somehow formed in the reaction mixture, So beware of that.

blogfast25 - 29-1-2015 at 09:38

Quote: Originally posted by jhonthebaptist  
I made some I2 before with ammonium iodide tincture from the store. After I dried it, it was was about the size of a pea. I accidentally dropped it on the floor and it exploded, more like a purple fire cracker. Nitrogen tri-iodide was somehow formed in the reaction mixture, So beware of that.


Describe exactly what you did?

jhonthebaptist - 29-1-2015 at 17:24

It was years ago so Im a little foggy . I think I just acidified with excess sulfuric acid to precipitate the I2. When it hit the floor it was more like a loud pop as opposed to exploding, it was a surprise for certain. Hope this bit of random info helps someone, for safety sake.

blogfast25 - 30-1-2015 at 07:18

Quote: Originally posted by jhonthebaptist  
It was years ago so Im a little foggy . I think I just acidified with excess sulfuric acid to precipitate the I2. When it hit the floor it was more like a loud pop as opposed to exploding, it was a surprise for certain. Hope this bit of random info helps someone, for safety sake.


That doesn't make a lot of sense: NI3 is prepared simply by combining NH3 with I2. An acidified solution of ammonium iodide tincture CANNOT contain any free NH3.

[Edited on 30-1-2015 by blogfast25]

jhonthebaptist - 30-1-2015 at 07:41

well Im telling you what happened, not to sound smart. I know it dont make sense, but it happened. I know what you are saying is true and I have no explanation HOW it happened but none the less it must have had some free ammonia in there before all the acid was added, thats all I cant come up with. Please understand that Im not making this up and if you don't believe it then theres nothing I can do. I dont use iodine tincture any more for iodine after that, the other tincture made with alcohol is fine and never had a problem when I used it. So I don't know what else to say.

here is the tincture that I used.

[Edited on 30-1-2015 by jhonthebaptist]

k2-_87dc7df9-20d6-4316-a7e9-55b12f6e9013.v1.jpg - 20kB

blogfast25 - 30-1-2015 at 09:55

It's not a question of 'believing/not believing' you, only one of trying to get to the bottom of things.
Quote:
it must have had some free ammonia in there before all the acid was added


In that case the original product would have contained some NI3. Also unlikely.

gdflp - 30-1-2015 at 10:04

I've used this brand before to isolate iodine, but using acidified peroxide instead of sulfuric acid. It doesn't actually have any free iodine in it, it is a solution of ammonium and sodium iodides dissolved in ethanol. Some ammonia is dissolved in the ethanol to denature it, I don't think that NI3 can form from NH3 and iodides.

blogfast25 - 30-1-2015 at 10:35

If it doesn't contain any free iodine how can it have antiseptic properties?

Using acidified peroxide to oxidise the NH4I to free iodine would not liberate any ammonia and thus also no possibility of NI3, which the Baptist invokes for the exploding iodine.

[Edited on 30-1-2015 by blogfast25]

gdflp - 30-1-2015 at 10:44

Exactly, I had no issues with the synthesis. I have no idea why, but there is no significant free iodine in the solution, the ingredients on the bottle are listed as "45% alcohol denatured with ammonia, ammonium and potassium iodides, and purified water". Search for "decolorized iodine", it seems to be more of a folk remedy rather than actually having much of an effect.

jhonthebaptist - 30-1-2015 at 15:28

I may have used hydrogen peroxide and HCL. It was 5-6 yrs ago. I know what what happened when I dropped it, so it dont matter to me. dont really care if you believe or not. You just need a reason to point your finger. I will tell you this, next time I see a potential hazard, or I have had experience in a subject, I will remain quiet . Dont even know if it would have caused a problem with what I wanted it for. So for me this is the end of this topic, go try it and run it through a mass spec. then you can see for yourself. just cause you dont know me, dont disregard the message. kind regards and blessings

blogfast25 - 30-1-2015 at 16:33

AGAIN, no one here is claiming they don't believe you, nor am I pointing fingers.

You made a very specific claim:
Quote:
Nitrogen tri-iodide was somehow formed in the reaction mixture,


It's normal, desirable even, that on a science forum some will want to question that, or understand better what caused the explosion, especially since as the circumstances in which you prepared the iodine do not seem conducive to NI3 formation.

If you can't understand that and decide, rather childishly, to take it personal then you have definitely chosen the wrong hobby.

[Edited on 31-1-2015 by blogfast25]

Muzz1969 - 1-2-2015 at 03:52

You can get 10% iodine solution by the litre from equine supply stores.

j_sum1 - 1-2-2015 at 04:06

Really? What is its intended purpose? Is this a universal practice? How economical?

morganbw - 2-2-2015 at 03:02

Quote: Originally posted by j_sum1  
Really? What is its intended purpose? Is this a universal practice? How economical?


It is available but I would guess you would have to pass yourself off as a farmer with livestock or horses. I would wager that there would also be some id required and papers to sign.