Author Topic: KI crystals  (Read 1261 times)

0 Members and 1 Guest are viewing this topic.

bucockey

  • Guest
KI crystals
« on: March 12, 2002, 03:17:00 AM »
swim looked through tfse and found an archaic post saying that KI (potassium iodide) crystals should bee treated the same way that iodine tincture should, however, there was nothing said about what to do regarding the crystals:
should they bee dissolved in h2o?
if so- how much? (swim assumes warm h2o)- or- is there something better to dissolve them in so as to help keep the moisture down (making drying them a wee bit easier)
or should they just be crushed with a mortar and pestle?

ARRRGGH!.....I blow a fart in your general direction

pickler

  • Guest
Re: KI crystals
« Reply #1 on: March 12, 2002, 03:51:00 AM »
Keep your crystals in a dark jar that is air tight. Try th esearch engine, there is somethings here about storing iodine.

We'll soon find out if I'm a chemist or not!

PrimoPyro

  • Guest
Re: KI crystals
« Reply #2 on: March 12, 2002, 04:02:00 AM »
bucockey: What is your question? Is it how to reclaim iodine crystals from KI, or is it regarding storage of KI?

I have NaI, and I just store it in a plastic bottle, capped tight, in a cool temperature desk drawer. They have been fine for several months.

Iodide salts are not staining, so they need not be treated as such.

                                                   PrimoPyro

Vivent Longtemps La Ruche!

terbium

  • Guest
Re: KI crystals
« Reply #3 on: March 12, 2002, 04:02:00 AM »
What do you want to do with your KI? Store it or convert it to iodine? If you want to convert it to iodine then you dissolve it in water and treat like tincture.

bucockey

  • Guest
Re: KI crystals
« Reply #4 on: March 12, 2002, 10:51:00 AM »
terbium- that was my question... I assumed that it should be dissolved first.  I saw an early post by rhodium i believe that said to treat it as if it were tincture, but no mention on if it should be dissolved
thanks-

ARRRGGH!.....I blow a fart in your general direction

pROcon

  • Guest
Re: KI crystals
« Reply #5 on: March 13, 2002, 12:44:00 PM »
OR


Electrolysis of potassium iodide to form iodine

To electrolyze a potassium iodide solution. Electrolysis is a process by which a chemical reaction is carried out by means of the passage)of an electric current. As the reaction proceeds iodide is oxidized at the anode (negative) while water is reduced at the cathode (positive).

2I--->(aq) I2(s) + 2e-2H2O(l) + 2e- --> 2OH-(aq) + H2(g)

net reaction: 2I-(aq) + 2H2O(l) -->I2(s) + 2OH-(aq) + H2(g)

The cathode will be recognized by bubbles (H2) on the electrode and pink phenolphthalein indicator from hydroxide production. Phenolphthalein turns pink in the presence of base and clear in the presence of acid. A slight yellow/brown color to the water around the anode may be observed. This is due to a small amount of iodine being dissolved in the Water.

Materials:
alligator clips (4)
9V battery
insulated wire
solid potassium iodide
spoon
carbon electrodes ( led removed from two pencils )
shallow bowl (clear glass or white plastic a beaker would be perfect)
white paper
Procedure:
Add some KI (about the size of your baby fingernail) to the bowl, fill it half full with water and stir until the KI is dissolved. Put a white piece of paper under the bowl if it is a glass bowl.
Connect the wire to the alligator clips.
Clip one alligator clip to the tip of the pencils. ( Remove the led from the pencils for use as electrodes ).
Attach the other ends of the wires to the battery.
Place the electrodes in the bowl so that the pencil tip is in the solution.
Observe the electrodes for evidence of reaction. You will observe a pink color to a red color with a saturatted solution.
To produce iodine for collection you would want to use a saturated solution of sodium iodide.
How much current will be required to liberate 10 g of iodine from potassium iodide solution in 2 hours ? (Eq. wt. of I2 = 127.0)
[ Ans. 1.06 amp ]

[source:

http://www.geocities.com/dcarrd2000/iodine_info_101.html

]

There's another methods by bubbling clorine gas through a H2O/KI or NaI solution that also looks doable, and good fun!  :)
But nothing as simple as the electro method above.
Will try it asap, can't wait!  :)  8)

Got the URL from the nice bee in the currect seaweed/iodine thread yesterday, and found that further down the page.

I wonder if any water soluble iodide would do? this may be a non-issue because I don't think the two mentioned would be difficult to find but ill ask anyway for personal interest.

pROcon

don't call me...I wont answer, or call you back.

urushibara

  • Guest
Re: KI crystals
« Reply #6 on: March 14, 2002, 05:31:00 AM »
Seems to me the dH2O/HCl/H2O2 method pulls the KI out of tinctures - looked like about 4g out of two 50ml bottles of 2% I2 2.5%KI. If you were storing the iodine for long term, it would be best in a dark-brown glass or black plastic as KI.

If you've got KI in solid form, just use 2.5x as much h20 as you would use in a standard tincture (hcl/h2o2) extraction.

Or am I wrong about Iodine coming out of the salt with the addition of HCl and H2O2... It makes sense to me - if chlorine gas pulls KI apart and leaves I2, though it progresses further, which makes the HCl method better. The standard tincture extraction works even better, because the HCl preferentially substitutes for the I and makes KCl and the I2, as the KCl forms, the I becomes less soluble and crystallises out of solution. What function does the H2O2 perform?

I know naaaathing.

pROcon

  • Guest
Re: KI crystals
« Reply #7 on: March 14, 2002, 06:03:00 AM »
Urushibara


Or am I wrong about Iodine coming out of the salt with the addition of HCl and H2O2... It makes sense to me - if chlorine gas pulls KI apart and leaves I2, though it progresses further, which makes the HCl method better. The standard tincture extraction works even better, because the HCl preferentially substitutes for the I and makes KCl and the I2, as the KCl forms, the I becomes less soluble and crystallises out of solution. What function does the H2O2 perform?




Nope, your spot on.
Okay so we have the HCl containing the NaI/KI, then some H2O2 added to the HCl/NaI or KI solution...the H2O2 gives off one of it's Oxygens to the HCl (which is at that point liberated of it's Clorine molecule). So the HCl becomes H2O, and the H2O2 which has lost an O also becomes H2O.

The clorine as you said, liberates the I from the iodide, to become I2, elemental iodine, which is insoluble in water, so then it's filtered out!  :)  8)

Learnt that last night from I think Osmium! After I posted about the electrolysis, (which I better note is better suited to NaI, as opposed to KI, as it says further down on the URL I sent, but they could both be used).

Hope this helps!

pROcon  :)


don't call me...I wont answer, or call you back.

terbium

  • Guest
Re: KI crystals
« Reply #8 on: March 14, 2002, 06:27:00 AM »
Or am I wrong about Iodine coming out of the salt with the addition of HCl and H2O2
You are not wrong.

Post 280939

(terbium: "Re: KI crystals", Chemicals & Equipment)


It makes sense to me - if chlorine gas pulls KI apart and leaves I2, though it progresses further, which makes the HCl method better. The standard tincture extraction works even better, because the HCl preferentially substitutes for the I and makes KCl and the I2, as the KCl forms, the I becomes less soluble and crystallises out of solution. What function does the H2O2 perform?
Even though your reasoning is.

Post 213974 (missing)

(terbium: "Re: OTC Iodine synthesis", Chemistry Discourse)


terbium

  • Guest
Re: KI crystals
« Reply #9 on: March 14, 2002, 06:31:00 AM »
The clorine as you said, liberates the I from the iodide
Nope, the chloride is irrelevant.

4I- + 2H2O2 + 4H+ = 2I2 + 4H2O

pROcon

  • Guest
Re: KI crystals
« Reply #10 on: March 14, 2002, 11:44:00 AM »
terbium, I'm sure you'd know better.

pROcon



don't call me...I wont answer, or call you back.

EzeKieL

  • Guest
WHy don't you just make HI with your KI .
« Reply #11 on: April 10, 2002, 11:43:00 PM »
WHy don't you just make HI with your KI .  There's a post around here giving detailed procedure for making HI from KI and phosphoric acid.

malvaxman

  • Guest
I think ..
« Reply #12 on: April 13, 2002, 07:13:00 PM »
I think I have seen one of this this "carbon electrodes" falling apart during the procedure contaminating the solution. :(  

Use HCL, H202,and nonpolar instead. :P

hermeticsghost

  • Guest
Why not HI from KI, here's one reason
« Reply #13 on: April 14, 2002, 03:02:00 AM »
Because bees with redP can use I2 for a fairly quick rxn like one to two hours, as opposed to first distilling HI off of KI/H3PO4 then redistilling for purity then refluxing for 25 hours followed by a period of 12 hours of letting it set (from Rhodium's site) and then basifying a comparable buttload of acidic solution, etc.  However, since no redP exists for me anymore, HI is my wave of the future.

pROcon

  • Guest
HI
« Reply #14 on: April 14, 2002, 02:35:00 PM »
I've seen in a lot of articles rthat the reason why HI was scheduled was because it could be used to reduce E, and so cooks use rp+i2 to do so.

Now after I read that VERY impressive HI writeup I was like wow. But any HI reduction I found still required rp, so I thought what is the point? maybe someone can inform me.

Also it says 1kg of KI makes 1ltr of HI.
Now 1kg of KI could theoretically yeild about 765gm of I2.

Whats the better deal?

pc

don't call me...I wont answer, or call you back.

hermeticsghost

  • Guest
HI reduction w/o redP
« Reply #15 on: April 14, 2002, 03:04:00 PM »
This thread may answer your questions about no redP.  Read it all, because some corrections are made further down.

Post 288929 (missing)

(Rhodium: "Hydriodic Acid From Pinene and Iodine", Stimulants)

myles

  • Guest
potassium iodide
« Reply #16 on: November 02, 2002, 03:01:00 PM »

nutlin

  • Guest
To get iodine from KI, the simplest method by far ...
« Reply #17 on: November 02, 2002, 07:24:00 PM »
To get iodine from KI, the simplest method by far is gassing with Cl. Belive me, i've tried alot of the methods and Cl is the quickest, cheapest and most effective route.

It doesnt take alot of gassing, and as long as you work outside and have a proper setup (addition funnel, etc.) then you shouldnt ever smell the chlorine.

I dont see why everyone hates working with Cl so bad.

terbium

  • Guest
Iodine monochloride
« Reply #18 on: November 02, 2002, 09:11:00 PM »
To get iodine from KI, the simplest method by far is gassing with Cl. Belive me, i've tried alot of the methods and Cl is the quickest, cheapest and most effective route.
I would have thought that this would produce significant amounts of iodine monochloride.

Merck Index entry for Iodine monochloride:

  5038.    Iodine Monochloride. 
  Wijs' chloride.  ClI; mol wt 162.36.  Cl 21.84%, I 78.16%.  ICl.    Prepd from the elements:  Cornog, Karges, Inorg. Syn. 1, 165 (1939); Buckles, Bader, ibid. 9, 130 (1967).
          Black crystals or reddish-brown liquid.  The crystals occur in two modifications:  .alpha.-form (stable), black needles (ruby red by transmitted light), mp 27.2 deg; .beta.-form (labile), black platelets (brownish red by transmitted light), mp 13.9 deg.  bp 97 deg (decompn).  d429  3.10.  Sol in water, alc, ether, CS2, acetic acid.  May be stored in brown glass-stoppered bottles.  Not hygroscopic, but forms I2O5 in the presence of air.
          Caution:  Attacks the skin, forming dark, painful patches (effective countermeasure:  immediate washing with 20% HCl).

          USE:  In Wijs' soln (iodine monochloride in glacial acetic acid), used to determine iodine values of fats and oils.
          THERAP CAT:  Anti-infective (topical). 



Baseline Does Not Exist.