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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: 7453K on October 27, 2008, 06:08:41 PM

Title: seperating iodine from tincture of iodine, and other questions
Post by: 7453K on October 27, 2008, 06:08:41 PM
hey, first off ill say i am not sing this to make meth haha, im looking to procure iodine crystals to add to inks. ive heard of using hydrogen peroxide, in a 3 to 1 ratio, but ive also heard you need to add hydrochloric acid...how do i do this?

and also, ive heard someone say they made hydroflouric acid from electrolysis, but i dotn know what i would start with?
and ive heard of people using phosphoric acid to etch glass, bt as far as i know, hydroflouric acid is the only thing that can do this. are there any chemicals besides hydroflouric acid that can?
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: macman104 on October 27, 2008, 07:32:33 PM
For the iodine, I'm not sure about the regulations, but they sell iodine crystals (although, I don't know how cheap they are).

For the HF, sorry, but why would you even want to think about making some on your own?  That stuff is nasty, and cause severe harm to yourself...
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: macman104 on October 27, 2008, 08:25:12 PM
I checked, you can buy iodine chips for ~50cents/gram from Sigma-Aldrich.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: azmanam on October 27, 2008, 08:47:02 PM
I'm gonna second the motion not to work with HF.  Do not make HF yourself.

http://en.wikipedia.org/wiki/Hydrofluoric_acid#Safety
http://pipeline.corante.com/archives/2004/03/03/things_i_wont_touch_1.php
http://www.bt.cdc.gov/agent/hydrofluoricacid/basics/facts.asp
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: 7453K on October 27, 2008, 08:47:28 PM
alright thanks, and yea i wasnt plannign on making the hydroflouric acid, it appears to be the most dangerous acid hha, i was just wonderign how its made. and do you know about phosphoric acid?
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: Arkcon on October 27, 2008, 09:15:11 PM
You can buy the phosphoric acid at a hardware store, it's in a product called naval jelly, for stripping the rust off of iron railings and such.  It is a fairly mild acid, so it has no effect at all on glass.  Glass can be etched with alkali, but household strength, as is found in drain cleaner, won't do much to glass, beyond making a few scratches.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: azmanam on October 27, 2008, 09:17:33 PM
You could buy a Dremel or something and scratch designs into it directly.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: 7453K on October 27, 2008, 09:19:43 PM
well a dremel is out of the question. i need it for a liquid that will flow through a marker and etch glass. so phosphoric acid wont work? does anyone know the main ingredient in armour etch then? because thats in craft stores to ecth glass, apparently it dissolves limestone.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: Arkcon on October 28, 2008, 10:53:58 AM
Well, a little Googleing says that Armour Etch is a paste containing hydrofluoric acid.  Probably well buffered, and diluted, maybe with the calcium-rich paste already added, for user safety.  If you really want to etch small decorative pieces of glass, I'd buy it, and follow instructions carefully.

http://www.psfk.com/2005/02/armor_etch_some.html

As I recall, there was a controversy over TireShine products, apparently they contained really diluted HF.  Unfortunately, they arrive at the car wash as a concentrate, and, well, the average car wash workers probably didn't ace high school chemistry. ;D
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: 7453K on October 28, 2008, 03:48:47 PM
alright yea etch bath is the best bet no doubt. but etch bath, (the thin etch)is realy hard to come by. the most common is etch cream, which is pretty thick. and i was wonderign what i coudl thin it with, without sacrificing quality too much.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: 7453K on October 28, 2008, 10:00:49 PM
also for sulfiric acid, it dissolves most metals correct? im looking to buy some, is 26$ on sigma aldrich a good price for 500ml? wierdly enough, its 25$ for 100ml go figure. and what are soem precautions i shoudl take? liek how dangerous is it compared to hcl, which you can liek dip you hand in wash it off and be fine
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: Arkcon on October 28, 2008, 10:55:16 PM
also for sulfiric acid, it dissolves most metals correct?

Not really.  Sulfuric is very reactive to organic materials, because it is a dehydrating acid.  It reacts with many metals, but not all.  Nitric is a powerful oxidizing acid, and dissolves many metals ... except for the one's it passivates -- actually reacts to form a more resistant coating.

Quote
im looking to buy some, is 26$ on sigma aldrich a good price for 500ml? wierdly enough, its 25$ for 100ml go figure. and what are soem precautions i shoudl take? liek how dangerous is it compared to hcl, which you can liek dip you hand in wash it off and be fine

Significantly more.  If you get moderate strength sulfuric on your hand, you will know it instantly.  Anything that chars paper in seconds will get your hand hot very quickly.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: azmanam on October 29, 2008, 06:39:13 AM
An example - I was pipetting con'c sulfuric acid for a reaction I was doing.  I was wearing a sweatshirt at the time.  I would draw some sulfuric acid into the pipet and transfer the pipet to whatever flask I was adding it to.  During this transfer, my arm would hover over the open bottle of acid.  The fumes were corrosive enough to eat holes in the sleeves of my sweatshirt.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: 7453K on October 29, 2008, 03:53:16 PM
damn! that must have sucked. online it says it dissolves some stainless steels which is why i was interested, but i really dont want to mess with anything that will ruin my s#*$ that easily, what was the concentration?
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: azmanam on October 29, 2008, 03:58:06 PM
concentrated (96%) sulfuric acid is 18 molar.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: 7453K on October 29, 2008, 04:09:58 PM
sorry im only a high school student, what does that mean? the 18 molar part?
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: azmanam on October 29, 2008, 04:21:30 PM
In 1 liter of con'c sulfuric acid, there are 18 moles of sulfuric acid.

http://en.wikipedia.org/wiki/Molarity
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: 7453K on October 29, 2008, 04:32:58 PM
oh alright thanks mang.
Title: Re: seperating iodine from tincture of iodine, and other questions
Post by: Arkcon on October 30, 2008, 09:03:32 AM
Since the forum skin's change, I've found it almost impossible to get a meaningful search -- that Google search applet in the corner misses things, so I'm getting this old message to you a little bit later than I'd hoped.  At any rate, we talk about acids, and human skin, here:

http://www.chemicalforums.com/index.php?topic=23805.msg90436#msg90436

And it links to another thread on the subject, tangentially connected.