Author Topic: Iodine screw up  (Read 42856 times)

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  • Guest
Iodine screw up
« on: November 06, 2004, 06:57:00 PM »
Is there anything one can do if too much acid was added to 9.4% tincture 1 pint, added 200mL instead of 2 oz.


  • Guest
for xtals...
« Reply #1 on: November 06, 2004, 08:59:00 PM »
i never really measure that precicely when crashing iodine. i just add equal parts of hcl and peroixde. adding more of either never increased or decreased yeilds for me. but im not a chemist, i just follow directions well.


  • Guest
Dilute with a little more water
« Reply #2 on: November 06, 2004, 09:44:00 PM »
Dilute with more water; you will already have crystals by the time I post this reply.... just remember to rinse that I2 very very well to remove all the traces of HCl from it. Otherwise the I2 will degrade rapidly, likely as you try to dry it in a coffee filter... and a large portion of it will remain in the coffee filter as black sludge.


  • Guest
2% Iodine tinc
« Reply #3 on: November 06, 2004, 10:00:00 PM »
Ibee made that mistake of adding too much HCL once to 2% tinc and it turned the solution clear...never to be seen again.
Did the same thing with too much h2o2 once...same thing! Turned clear....never to be seen again.

Adding h2o didn't help in Ibee's case.

Geez if the excess h2o fails to produce I2 xtals could T_C try this?

My idea in hindsight, since Ibee trashed that botched excess acid tinker, he didn't try this but might now if faced with the same invisible crstals:
If the xtals won't precipitate in solution, couldn't one try to nueutralize the excess acid with NAOH to account for the excess 141ml hcl



  • Guest
past experience...
« Reply #4 on: November 07, 2004, 03:42:00 PM »
Past experience suggests that for 9.7% tincture the amount of HCl is too much, but not so much that you can't get crystals.  I know folks who use that much acid on a pint of  7?% tinc. Two percent? That would be WAY too much HCl... and you would have sludge when you were done, if anything.

You can bring the pH up and neutralize the acid with NaOH... but if you use crystals after doing this, be sure to resublime them before use. The crystals always seem to have some base in them if you don't resublime them... even with repeated washings with dH2O... and that will impact the reaction in a negative way.


  • Guest
And don't add too much NaOH, it can dissolve...
« Reply #5 on: November 07, 2004, 07:54:00 PM »
And don't add too much NaOH, it can dissolve iodine as hypoiodite. I'd use sodium (bi)carbonate for neutralization instead.


  • Guest
Well, thought the same thing when originally...
« Reply #6 on: November 08, 2004, 02:29:00 PM »
Well, thought the same thing when originally posted this so added about 300ml of 20% NaOH/dh2o and still sludge on the bottom but did notice something happening, think that it has thickened up some.  Really sucks to fuck up a pint of that high of tinc.  Went immediately and bought a 7% tinc and got back about 30 grams from that but still want to try and recoup the other.  Will add another 150ml NaOH and continue dilluting with water.  Don't have to do the iodine too often and had procedure written down wrong in papers.  Won't ever make that mistake again.


  • Guest
are you deaf?
« Reply #7 on: November 08, 2004, 03:07:00 PM »
DONT use NaOH but sodium carbonate or better sodium bicarbonate (baking powder) to neutralize the excess acid as moo told you.
But you probably have fucked it up completely by now.


  • Guest
Added NaOH the other day before reading ...
« Reply #8 on: November 08, 2004, 04:28:00 PM »
Added NaOH the other day before reading thread, no my hearing is fine!!  Will try baking soda.


  • Guest
dry that sludge...
« Reply #9 on: November 08, 2004, 04:36:00 PM »
Dry that sludge, and resublime the I2 in it before you use it.


  • Guest
That's the ticket!
« Reply #10 on: November 08, 2004, 11:44:00 PM »
Regardless of the base used, it's still obtainable.
Yeah it's better to do with a weaker base
Now in the case of 2% Iodine tincture, can someone please explain why Ibee's two separate cases of excess chems turned his solution clear???
NO SLUDGE! No sign of I2....clear as water!
Clear with excess hcl.
Clear with excess h2o2.
Is there a recoverable remedy for clear solution due to excess chemical additions?
Logic suggests bring the pH back UP!

Ibee switched to the more favorable, less chem, method of using h2so4 and bleach since that time for tincture treatment.

But he trashed those other botched batches because he couldn't find any info on the subject.

For a lack of knowing exactly what to do, or the proper steps and measurements needed, how's about someone offer up some useful information to help an inevitable situation such as this.
If it was offered...excuse me...I missed it!
The most logical route would be to use the same chems used in recovering I2 from the HI/RP rxn waste.
Last time I was NAOH to reach an equilibrium in strong acidic to collect the organic, then hcl to bring back the savagable I2.
So excuse my skeptisism on seeing SodiumBicarb as the better of the two bases in trying to balance 141ML HCL extra! That's a shitload extra!
I've been known to be wrong before.
So I fail to see the logic in shoving sodium bicarbonate down someones throat when it isn't suggested in I2 Recyling from spent rxn solution.
Any brainiacs care to clear THIS UP???


  • Guest
could be...
« Reply #11 on: November 09, 2004, 12:10:00 AM »
There is only 28% as much I2 in 2% tincture as there is in 7% tincture. If you use the same ratios for peroxide and acid, or bleach and acid, as you would use to precipitate the iodine crystals from 7% tinc, you are using three to four times the amount of oxidizer you need to add to get the iodine to fall out.

The reaction that yields those gray crystals works within a range in excess of the molar amount of oxidizer or acid the reaction really needs. The amount I suggest using... the one volume of 3% peroxide to one volume of 7% tinc.. is in excess of molar amounts needed to do the job. If you go too far over the molar amount you oxidize the iodine or you cause a different reaction and wind up with something besides I2... like the clear crystals you get if you add too much bleach or sulphuric acid using that method.


  • Guest
120ml dh2o 1 pint of 9.4% titratable Iodine...
« Reply #12 on: November 09, 2004, 05:49:00 PM »
120ml dh2o
1 pint of 9.4% titratable Iodine Tincture
Suppose to be 2 ounces of HCl wrote down switc's info wrong last time and wrote 200ml instead.
1 pint of H2O2

Mixed water and acid, then added tinc.  Next added 1 pint of H2O2 over 30 minutes with lots of swirling.  Well, then swims know the rest.  Have added a total of 200ml of 20% NaOH then added about 5 grams of sodium bicarbonate, dam it's a fucking volcano, fizzed, bubbled and overflowed a little.  Still no iodine xtals, going to try evapping and then subliming.  Any thoughts?  Swim had done this same thing once before only because Iodine procedure doesn't have to be performed that often.  Will never make that mistake again.


  • Guest
Whats in the flask?
« Reply #13 on: November 10, 2004, 10:17:00 AM »
Before adding anything else, what do you see in the flask? Is the mix violet? Is it a dark dark color or a weak color? Is there any sludge, xtals or otherwise? the reason I ask, is that you could just pour off the solution if most of the I has dropped out, and work on the I without all the froth and mess of the acid base battle ground. Save the solution for experimenting with if you believe there is a considerable amount of obtainable I still in it, but don't expect alot of success. 200 ml. WOW! Yeah without a doubt you got a fizzy goin there, heheheheheh B.T.D.T. :-[


  • Guest
The solution is in a 1 gallon milk jug with an
« Reply #14 on: November 10, 2004, 05:50:00 PM »
The solution is in a 1 gallon milk jug with an orangish-brown layer on bottom about 1/2" thick while the rest is almost clear.  Will experiment with the mix and see what comes out.


  • Guest
« Reply #15 on: November 10, 2004, 07:16:00 PM »
Last time I was NAOH to reach an equilibrium in strong acidic to collect the organic, then hcl to bring back the savagable I2.
So excuse my skeptisism on seeing SodiumBicarb as the better of the two bases in trying to balance 141ML HCL extra! That's a shitload extra!

The bases in question are used for different things. In the case of treating a post-reaction mixture you are trying to make the solution so basic that you can extract the amine out. In the case of this thread, which is correcting a mistake made while trying to get I2 from tincture, the point of adding carbonate is to make sure the solution gets neutralized and make sure the mixture doesn't get too basic. For that purpose (bi)carbonate is the better choice, believe me.


  • Guest
Thanks Moo
« Reply #16 on: November 11, 2004, 01:08:00 AM »

I suppose my thinking was in reverse, as is evidenced by the sludge T_C has to deal with.
It's still hoped that an equilibrium can be reached to have the I2 xtals precipitate out of solution.
It still has to be there!
What about adding alcohol?
Might that dilute the solution some after bringing back to a neutral-ish pH?
And then possibly finishing from there.
My initial thinking centered around 141ml hcl being ~3 times the amount necessary!
That seemed like it would require a whole heap of basing to bring it back!