Picric-A
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Iron Ethanedioate (oxalate) stains
Hi, after making some Iron ethanediote for pyrophoric iron i have got nast yellow stains everywhere, all over my sink, stirring rods, pestel and
mortar and worse still my precious glassware and impossible to clean buchner funnel.
Now i tried using boiling NaOH to get rid of these but had no success... i have also used;
boiling sodium percarbonate
boiling dil. H2SO4
boiling H2O2
and boiling sodium carbonate
none of these worked...
Can somebody please tell me what will remove these?
thanks
Edit by chemoleo: title spelling. Further incidents of 'diotes' are to be seen as oxalates.
[Edited on 16-8-2009 by chemoleo]
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not_important
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citric acid (even lemon juice), oxalic acid, and various other reducing and complexing agents. Even SO2 in water works on mild stains, but thicker
stains require additional SO2, both a reducing agent and an acid.
Almost everything you used was sure to precipitate iron and/or oxidise it to Fe(III). Hot alkaline material can make the stains more difficult to
remove.
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kclo4
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Iron out is a cleaner sold at walmart which contains sodium dithionite (sp?) and sodium bisufite. When it is added to water SO2 is formed to some
degree.
Iron out, as the name might suggest, is probably used for removing rust stains 
Rust stains on glass are easily the most difficult stain to remove. Also try swirling sand and water w/iron out in it. The sand really helps clean the
glassware.
[Edited on 14-8-2009 by kclo4]
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Lambda-Eyde
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I'm guessing the stains are Fe2O3? Dilute phosphoric acid will remove it even at room temperature.
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kclo4
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Is iron phosphate even solubile? I tried removing some rust stains from glass using a phosphoric acid I bought at the store as a rust remover but I
did not have success. Did you do this first hand?
IIRC the phosphoric acid is used to prevent rust by forming a thicker insoluble layer of the phosphate.
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Lambda-Eyde
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I haven't tried it on glass before, but I have used phosphoric acid in a ceramic mortar and on an old rusty vice. Worked like a charm. I don't know if
iron phosphate is soluble in water.
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chemoleo
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Please specify what "Ethanediote" exactly is, and edit if there's a spelling error!!!
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Picric-A
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sorry i forgot to mention i used SO2 (aq) with no success...
i dont have access to dithionite but i guess aqeous SO2 works the same...
Nope it isnt a Fe2O3 stain, its a ethanediote stain... hence its difficult to remove
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Ozone
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I'm pretty sure ethanediote = ethanedioate, a complex chelate of iron with (for example) 1-3 oxalate ligands
(if 3+, iron(III)-tris-(ethanedioate), if 2+, Iron (II)-oxalate).
See (3+):
http://www.chemthes.com/entity_datapage.php?id=3994
For the synthesis of pyrophoric iron (see attached) iron(II)-ethanedioate (FeC2O4) is the intermediate.
Cheers,
O3
[edit] try CLR cleaner (attached)?
[Edit] further clarification; ETHANDIOIC ACID = OXALIC ACID!
Attachment: 22-1 demo Spontaneous combustion of iron.pdf (29kB)
This file has been downloaded 685 times
Attachment: CLR_01.pdf (70kB)
This file has been downloaded 600 times
[Edited on 15-8-2009 by Ozone]
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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DJF90
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You still havent said what "ethanediote" is...
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JohnWW
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Try nitric acid, or failing that aqua regia.
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kclo4
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ethanediote is oxalate isn't it?
Who uses ethandiote? Must be a cultural or regional thing I guess.
I figure iron ethandiote acts similiar to iron acetate, and eventually forms iron oxide when exposed to the air - at least some iron acetate I made
by reacting Fe with vinegar after a while left some iron oxide.
Have you tried using a torch with a reducing flame on it (fuel rich) perhaps?
If you can heat it, you'd be able to at least change it to iron, and then iron oxide.
Edit: Why would nitric acid or aqua regia dissolve iron oxides? I didn't think they would.
[Edited on 15-8-2009 by kclo4]
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DJF90
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There is no such thing as "ethanediote". What I think he means is "ethanedioAte", which is indeed oxalate. But who knows what he really means until he
clarifies it himself! I would expect Iron oxalate to be quite soluble, especially as oxalic (aka ethanedioic) acid is used to remove rust and rust
stains (IIRC).
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kclo4
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Yeah, I think it is iron oxide that fell out of the solution. Probably ought to just add more oxalic acid and heat it up to a boil or something.
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Picric-A
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yes i did mean ethanedioAte... just a spelling error, easy to make and yet you people make such a big thing of it even thought you blatently know what
i mean... 
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kclo4
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Yeah it is a simple mistake to make, but so is sulfate vs sulfite or nitrate, nitrite, etc. Considering most of us have not really heard of
ethanedioate, we were just making sure. So get all angry about it, because its not like you had the opportunity to clear up the confusion earlier by
answering chemoleo's question, which seems to have been ignored.
Either way, did you ever get rid of your iron oxide stains? 
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chemoleo
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Picric-A, the fact that so many people questioned you on what irondiote means, indicates you should have taken the opportunity to correct your error
right away (hangon, errors, as you made that accidental error more than once, even after my request to edit the error earlier), and
do so in the title as well. And since you haven't done it, in fact showed entirely inappropriate 'angry' signs, indicates you aren't exactly serious
about this thread, so I'll move it back to beginnings. I'll edit the title as well.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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chemoleo
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Thread Moved
16-8-2009 at 15:40 |
Picric-A
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I couldnt correct it straight away as i broke my laptop so it took 2 days to get fixed however i admit this should of been the standard action. It is
not however like nitrite nitrate becuase there is no so thing as ethanedioite... but i get the picture 
As for whether any of it worked, nope none have... i am pretty much out of ideas... maybe yellow stained glassware it is... 
P.S. i would be very surpirsed if people havnt heard of Ethanedioates as they are common chemicals.... especially the free acid.
[Edited on 17-8-2009 by Picric-A]
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DJF90
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Oxalate is much more frequent in literature. Ethanedioate is IUPAC nomenclature I believe, and as such is a bit OTT when oxalate suffices just as
well. Just like propan-2-one and acetone, or 2-methylpropan-2-ol and t-butanol. A good chemist will recognise both, but the older nomenclature
generally comes out on top. Wouldnt hurt to try aqueous acetone with salt added as an abrasive, and swirling the flask. Failing that I'm sure a wash
with dil. HF would do it, or a soak in a base bath.
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zed
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Many Salts of Oxalic Acid are insoluble, insoluble, insoluble. Looks like you have one, and unfortunately it is colored.
You could try soaking in a Glycolic Acid(a cousin of Oxalic Acid) solution, also known as CLR. It does remove rust stains. And, it might slowly
leach the Iron out of your Iron Oxalate.
Likewise, you could attempt to displace the Iron, with a more reactive metal.
Like Aluminum.
Another option, is to destroy the pesky oxalic acid skeleton, with an oxidizing flame.
Left behind will be Iron Oxide, still a possible problem, but a less esoteric problem.
With a little luck, you will be able to wipe most of it off.
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Picric-A
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When i used the filter flask to generate chlorine that removed the stain after about 2 hours contact with the mix. The chlorine generation mix was
TCCA + HCl. What could of removed the stain here?
The problem is the stain is on the inside of the flask so an oxidising flame would not work.
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zed
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Well, it appears elemental Chlorine is able to tear Iron from the viselike grip of Oxalic Acid, at least momentarily. If the Oxalic Acid survives, I
would suspect that it might rebind that Iron fairly quickly. It appears that, mercifully, such reconstituted Iron Oxalate , if it is present, is no
longer welded to the surface of your glassware.
Perhaps Oxone plus NaCl/NaBr might achieve the same effect.
http://greencontroll.hu/EN_termekek_7.html
The metal extraction material at the bottom of this article may be relevant.
[Edited on 16-9-2009 by zed]
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Picric-A
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Yes i hope so, it did take a while though (2 hours) for the stain to be fully removed though and how can one remove the stain from my buchner funnel?
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entropy51
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If Cl2 removed it from your flask, you might want to soak the funnel in a solution of sodium hypochlorite or a slurry of calcium hypochlorite, perhaps
acidified slightly with say vinegar.
On the other hand, it could have been the HCl in the Cl2 generator, in which case a soak in HCl might do it.
Sincerely,
Retarded
[Edited on 16-9-2009 by entropy51]
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chloric1
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I dunno I have to check my literature but isn't ferric oxalate ,along with other metal oxalate complexes, soluble in excess alkali oxalate? Potassium
oxalate is easy to produce and MUCH more soluble in water than the sodium salt. Or for that matter, stong oxalic acid solution above 60 C should
work. I used the free acid to remove rust stains from mortar and pestile. Putting it in the sun helps too.
Fellow molecular manipulator
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