Iodine Crystals

[mr. nawtynuff]

Swim was digging around the internet for an alternative to Iodine Tinctures to create Iodine crystals, when he ran across a product that looked somewhat promising. Upon further inspection this is what was listed in it's MSDS:


Swim was wondering if anyone could share with him if this would a feasible source to obtain iodine crystals from? If so would the same procedure done to get iodine crystals from 7% iodine tincture apply here. Swim is unsure what the two elements are suspended in, however doesn't think that it's alcohol. Swim feels it is most likes just water, considering what it's original use is intended for. Swim would really be pleased to learn this would do the trick, especially when considering that 8 fl oz cost around $7.50, which isn't super cheap; but cheaper than present options (2% tincture).

[mr. nawtynuff]

Sorry to double post, but I just wanted to provide an update on some info I found regarding the unanswered question I'd posted above. The source of the information given below is from the "LoveToKnow Encyclopedia" which is based on the 11th edition of The Encyclopaedia Britannica (pub. 1911). And while this means it is rather dated info, it doesn't mean that it is incorrect. It states:

"Iodine may also be prepared by the decomposition of an iodide with chlorine, or by heating a mixture of an iodide and manganese dioxide with concentrated sulphuric acid. Commercial iodine may be purified by mixing it with a little potassium iodide and then subliming the mixture; in this way any traces of bromine or chlorine are removed. J. S. Stas recommends solution of the iodine in potassium iodide and subsequent precipitation by the addition of a large excess of water, the precipitate being washed, distilled in steam, and dried in vacuo over solid calcium nitrate, and then over solid caustic baryta."

Swim was thinking that he could convert the Potassium Iodide into Iodine by bubbling Chlorine gas into the solution. However can anyone tell him if he were to do this if the chlorine gas would alter or affect the Iodine that's already in the solution? Then he could just crash all of the iodine out of the solution as crystals using Hydrogen Peroxide. Is swim's logic presented here accurate or not? Obviously swim's biggest concern here is yielding the most iodine and if bubbling the chlorine gas will attack the iodine thats already in the solution it would be against swims intentions as this would be moving in the opposite direction for him as he wants a way to gather the iodine already present in the solution (10%), as well as convert the Potassium Iodide (10%) into iodine; and grossing the percentages of both. Hope that makes sense. Any knowledgeable comments would be greatly appreciated. Thanks!!!

[Eldorhan]

"Kings Chemistry Survival Guide", by Jared Ledgard offers 3 separate and distinct way to make Iodine from potassium iodine.

[yolbit]

SWIM has obtained some KI - potassium iodide (you can also use sodium iodide), he has decided on this method of extraction as it uses all OTC chems and is relatively easy. Potassium Iodide is an an easily aquired chem that can be found at photochem suppliers. It also yields high purity iodine crystals.


Procedure: Into a suitable beaker or container, place 250 milliliters (8.4 fluid oz.) of warm tap water, followed by 70 grams (2.5 oz.)
of bleaching powder. Thereafter, stir the entire mixture for about 1 hour, and then filter-off the precipitated solids (composed of
calcium hydroxide). Note: vacuum filtration works best, but if all you have is gravity filtration, place a small amount of clean sand in
the bottom of the filter paper before filtering. This will help aid in the filtration process, which can be a slow one.

After the filtration process, you will have a yellowish relatively odorless liquid. This yellow liquid will be composed of hypochlorous acid. Now, prepare a potassium or sodium iodide solution by adding and dissolving 50 grams (1.7 oz.) of potassium iodide, or 45 grams (1.6 oz.) of
sodium iodide into 200 milliliters (6.8 fluid oz.) of tap water, and then slowly add this iodide solution to your yellowish hypochlorous
acid mixture over a period of about 10 to 15 minutes.

After 10 to 15 minutes, stir the mixture for about 30 minutes, and then filter-off the precipitated brownish solids (composed of the crude iodine). Once the brown solids have been filtered-off, wash them with several
portions of cold water (use the same technique as in method 1 for washing), and then vacuum dry or air-dry these brownish solids.
Thereafter, place this dried iodine into a sublimation apparatus,
and then sublime the iodine to purify it.

This sublimation process should be repeated once more to produce what is called “double sublimed reagent grade iodine”, which will
have a purity of no less then 98% iodine.


Note: Sublimation is the reverse of condensation, where we go from solid, to vapor. To set up a sublimation apparatus. Place a beaker on a heat source, in the bottom of the beaker place your crude iodine that was previously filtered off.
On the top of your beaker place a ceramic dish large enough to cover the top, this should make an almost airtight seal. Fill this dish with icecubes.
Turn on your heat and adjust once your crude iodine starts to melt. From here the iodine will start to vapourise and condense back into a solid on the underside of your ceramic plate. Scrape this off and repeat again - this will yield 98% pure iodine.

[Points4Life]

Heh - I finally understand sublimation!

All those long days in Chemistry class seem so pointless now. . .

[JohnAdamsSr]

AFOF lives in Florida and can not get tinctured iodine. Where can he buy Potassium Iodide or sodium iodide? He says that the iodine crystals are good for purifying surface water for drinking on campouts.