MagicJigPipe
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PTFE by fluorine and polyethylene
I have always wanted to figure out a way to make my on PTFE. But then I discovered this on the Wikipedia definition of Teflon:
"it may be produced by the direct substitution of hydrogen atoms on polyethylene with fluorine, using polyethylene and fluorine gas at 20 °C.[7]"
I can't see any reason why it wouldn't work.
The only problem is safely producing fluorine gas, one of the most dangerous elements I can think of. And you would have to somehow vent or do
SOMETHING with the excess F and H.
If nobody wants to try it, I will. For some reason I have little fear of anything toxic. Except for fluorine and HF. But I have no propblem trying
this because I'm very interested in PTFE.
[Edited on 28-9-2007 by MagicJigPipe]
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not_important
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Normally the fluorine is diluted with nitrogen or some other inert gas. If that is not done the energy release is great enough that carbon-carbon
bonds get ruptured and you end up with little else but CF4 and HF.
Once a surface film has formed the rate of conversion drops off. This is useful for plastic containers that must be resistant to hydrocarbons, motor
oil containers are often so treated to give a interior layer of fluorocarbon. But if you are trying for bulk conversion it might be a problem.
The best way to handle the HF would be to capture it with KF, and return that adduct to the fluorine generation cell.
And saying "The only problem is safely producing fluorine gas" is both a large understatement and an oversimplification. Simply buying PTFE could
save large amounts of money that would be spent on hospital bills or funeral expenses.
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MagicJigPipe
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Ha! Yes, but I like being risky.
And that's exactly what I want to use it for. To produce a layer of fluorcarbon.
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woelen
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Are you serious, or are you trolling us? Fluorine is a NO GO in home chemistry. Simply forget it.
Only the best equipped labs in the world can handle elemental flourine in a safe way. Every item, you can find as a private person, will be rotten
away within minutes, when using fluorine. And besides that, you will not be able to obtain elemental fluorine.
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JohnWW
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Perhaps MagicJigPipe is, or thinks he is, resistant to attack by F2. For that, he would have to encase himself in a F2-resistant transparent plastic,
preferably PTFE or PVF. The stuff is usually generated by the electrolysis of a fused anhydrous ionic fluoride like NaF, KF, CaF2, or MgF2, using a
F2-resistant container and electrodes (something like Ni which is passivated, or Pt, and graphite), with some means of collecting separately the F2
and highly reactive metal produced.
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MagicJigPipe
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My skin is made of a super inert, F2 resistant material that has not yet been discovered.
And someone has to "push the envelope" so to speak. If people didn't do that nothing would ever happen.
I'm not saying I'm gonna just jump to it with my glassware and a raincoat. I'm saying, once I make a bit of money and get more experienced it would
be an awesome thing to try. Anything that a sophisticated lab can do, I can do with enough money and knowledge.
That's how new processes and discoveries get made. Doing stuff that "can't be done".
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MagicJigPipe
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"In 1986, preparing for a conference to celebrate the 100th anniversary of the discovery of fluorine, Karl Christe discovered a purely-chemical
preparation by reacting together at 150 °C solutions in anhydrous HF of K2MnF6 and of SbF5. The reaction is:
K2MnF6 + 2SbF5 → 2KSbF6 + MnF3 + F2
This is not a practical synthesis, but demonstrates that electrolysis is not essential."
I'm not suggesting it, it's just interesting. Nothing more.
And I also learned that most depleted uranium in the US is stored as UF6 in above ground containers! That just sounds like a disaster waiting to
happen.
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JohnWW
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Thanks for your purely chemical method of producing F2 gas, although with those reagents it woud be cheaper to produce by electrolysis. Besides, the F
needed to make those reagents in the first place would have had to come from somewhere.
Besides the isolation of F2 gas first being achieved in 1886, it quickly led in the same year to the discovery of the electrolytic method of
production of Al metal from Al2O3 refined primarily friom bauxite, by means of added cryolite, Na3AlF6 (originally a rare mineral found in Greenland)
to act simultaneously as an electrolyte, catalyst, and flux (to reduce the melting-point of the mixture), with graphite electrodes.
| Quote: | Originally posted by MagicJigPipe
And I also learned that most depleted uranium in the US is stored as UF6 in above ground containers! That just sounds like a disaster waiting to
happen. |
Why would they do that for? The depleted U-238 has no further use as UF6, but only as an analytical reagent (as fluorescing uranyl salts), as the
oxides (UO3 and U3O8) in glazes for pottery, and as the metal in depleted-uranium bullets and explosive shells on account of its hardness and high
density so as to maximize armor-penetrating power and kill as many Iraqis as possible both that way and through cancers caused by its extreme chemical
toxicity.
One would think that they would therefore want to recover the depleted U-238 for those purposes, and also recover the F2, initially as HF by
hydrolysis of UF6, for further enrichment of natural U for its fissionable U-235 in new batches of UF6 put through centrifuges or chromatographs.
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garage chemist
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The electrolytic method of fluorine synthesis is outlined in Brauer, with very detailed drawing of the electrolytic cell for lab scale preparation.
The electrolyte is molten KF*3HF which is electrolysed at rather mild 100°C, giving hydrogen at the cathode.
Mixtures of fluorine with inert gases, like 5% or 10% F2 in argon or nitrogen, are commercially available in gas cylinders for the specific purpose of
fluorinating PE tanks on the inside to make them resistant against mineral oil and gasoline.
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BromicAcid
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Additionally there is a thread around here detailing the method of running a high temperature fluorine cell. At one time I briefly considered
preparing fluorine but decided that although the cell was easy enough to produce (The original author expected the reader to buy the parts from the
hardware store) the anhydrous hydrogen fluoride would be a particularly difficult hurdle to cross in terms of ease to obtain as well as general
toxicity. And of course after I had the fluorine, even though I had a plan to use it there are both chronic and acute toxicity issues not to mention
the general considerations when handling the Tyrannosaurus Rex of the periodic table. I would just recommend against it.
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MagicJigPipe
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I agree it is a dangerous endeavour. That's kinda why I wan't to EVENTUALLY try it.
And I would be more afraid of HF acid than F. Simply because if you spill enough of it on you it's like certain death. And knowing you are going to
die would not be fun.
Maybe it's a subconsious thing where I wouldn't be able to see diluted F in open air. And it's harder to fear something you can't see.
And about the UF6 storage thing. Check this out.
http://www.wise-uranium.org/edum.html#CYL
If you wanted F you could steal it from one of those places! 
Kidding of course. Please don't conduct surveilance on me mr. Govt.
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chemkid
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I hope your aware that fluorine burns are ridiculous. They burn through your skin and bond with the calcium in your bones. So i would say that
fluorine is much more dangerous than hydrofluoric acid considering hydrofluoric acid is a liquid and if you can avoid spilling it. Fluorine just goes
into the air and find your skin and eats through it. I would recommend eventually be amended to never. (unless you've got serious contacts or talent
so you can get into a lab outfitted to handle it)
Chemkid
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JohnWW
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Many organic substances burst into flame if exposed to F2 gas in sufficient concentration. This may include even water-containing substances, like
biological tissues.
As for Garage Chemists's "Mixtures of fluorine with inert gases, like 5% or 10% F2 in argon or nitrogen, are commercially available in gas cylinders
for the specific purpose of fluorinating PE tanks on the inside to make them resistant against mineral oil and gasoline. ": F2 is capable of reacting
directly with N2 under conditions of moderate pressure and temperature or electric arcing to produce NF3 and intermediate products like N2F2 and N2F4;
and, under the most extreme conditions of temperature and pressure or arcing or radiation, may even combine with Ar to form ArF2, although it would
quickly decompose.
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Fleaker
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I wouldn't recommend working with fluorine unless you have some experience dealing with extremely corrosive and toxic materials (i.e. BF3, SOCl2,
PClx, Br2, Cl2, COCl2 etc). If your fluorine isn't dry, it will need to be dealt with using some specialty alloys.
To be honest, I would like to prepare some as well, but I am rather lazy and would rather buy it in a cylinder. Curiously enough, fluorine is cheaper
gram for gram than the xenon I need to buy. I really desire to do the xenon fluorides... maybe next year (if ever) I will post something.
Fleaker
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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MagicJigPipe
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Yes, I understand what F2 can do. Like I said, I know that it's more dangerous than HF but I am less scared of it. It defies logic, I know, but it's
just a subconsious thing because it's such a far-fetched substance/idea. Kind of like fearing a bullet flying at your face more than you fear nuclear
war.
And I do have experience with Cl2, Br2, PBr3 and PCl3 but I doubt I am prepared for F2.
Like I said. Some day when I have my own super advanced lab and lots of experience and equipment, I will try it. And I am confident I will succeed
without injury. All I have to do now is figure out a way to make lots of money.
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Ozone
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Need I mention that F2, while it is rendering you flesh (Pt in F2 glows), it is probably making HF?
Not entirely friendly. IIRC OH radical is directly beneath F2 n terms of REDOX potential.
quoted from wiki:
"It is so reactive that metals, and even water, as well as other substances, burn with a bright flame in a jet of fluorine gas. It is far too reactive
to be found in elemental form. In moist air it reacts with water to form also-dangerous hydrofluoric acid."
PTFE is made via polymerization of tetrafluoroethylene, not via perfluorination of poly-ethylene. I suspect that the treatement of PE with F2 would be
energetic.
Take care,
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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JohnWW
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That is right, Ozone. (BTW F2 is more reactive than even O3). Even Pt, at the bottom of the electrochemical series of metals, readily forms red PtF6
on direct reaction with the stuff, and this product is itself so strongly oxidizing that it can abstract electrons from gaseous O2, N2, and Xe to form
ionic hexafluoroplatinates(V).
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not_important
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| Quote: | ...
PTFE is made via polymerization of tetrafluoroethylene, not via perfluorination of poly-ethylene. I suspect that the treatement of PE with F2 would be
energetic.
... |
Most bulk PTFE is made that way. The direct reaction of dilute fluorine on poly-olefins is used to form hydrocarbon resistant layers on already
formed containers. See reference books such as http://books.google.com/books?id=ba7WwDbPbCUC&pg=RA12-PA...
and studies such as this http://dequim.ist.utl.pt/docentes/800/Artigos/2004_A45.pdf
[Edited on 4-10-2007 by not_important]
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MadHatter
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Teflon
Why do you want to make teflon when it is so readily availabe ? Fluorine is one of
those elements, I DON'T WANT TO PLAY WITH ! It scares the hell out of me ! I don't think
the NFPA has a corrosive rating high enough for this one. You're playing with something
worse than fire. IMHO, reconsider it. 
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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Jdurg
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I've actually got a sample of fluorine gas, albeit only about 3%, in a helium atmosphere inside a glass tubing. If you hold the tubing up to the
light at just the right angle with just the right background, you can kind of see a yellowish tint if you let your eyes adjust to it. Granted, over
time this 3% fluorine mixture will wind up becoming 0% as it reacts with the glass, but when mixed with helium I've heard that up to about 16% F2 can
be stored within glass containers for a period of up to a year or so.
With regards to F2 reacting with your body, I'd be more concerned with the F2 or HF reacting with the Calcium ions in my blood stream and interstitial
fluid than I would with my bones. It's the creating of super insoluble CaF2 in your blood stream that can cause the horrifically painful deaths
associated with fluorine.
\"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists of the unmistakable scent of broccoli, and usually
requires wiping afterwards.\"
http://maddox.xmission.com. |
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MagicJigPipe
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Wow, so many people are deadset on convincing me to reconsider. This may sound repetative but if the people who first isolated fluorine
"reconsidered" well, you know. I'm not saying I'm going to make some great discovery. But come on, SOMEONE has to do risky stuff. I will face my
fears, not run away from them. No one will convince me otherwise. I will do it when I have readied myself properly and no one will convince me to
back down. And really this is more about the production and safe handeling of fluorine than it is PTFE.
And I know fluorine is more dangerous than HF and how it reacts with various substances. I thought I made that clear. I was simply explaining a
misguided fear that I have.
And in response to Jdurg's post: Yes, the fluorine/HF reacting with the calcium in one's bloodstream and causing heart failure (among other things)
would be my greatest fear.
And, yes Ozone, PE + F2 is extremely energetic which is why it must be controlled and diluted.
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Fleaker
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Listen, a lot of us here do risky stuff, but we really try to avoid doing STUPID stuff. I (and other members) have worked on making SO3 from V2O5 at
the bench scale, and that compound is every bit as deadly as fluorine if you were to breathe any! If you're not equipped to handle it safely, don't
handle it. I am not afraid of fluorine, if I handle it correctly I will be fine. If I'm working without a hood, gloves, respirator, and face shield,
then I have a reason to be afraid.
Eventually I'll buy some, but not yet. It is a very interesting material, but I am really curious as to just how reactive it is--some of the stories
of its reactivity seem like hyperbole.
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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MagicJigPipe
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So, in theory, could one use a motor oil bottle to store HF in? Yes, yes, yes I know. "Go buy a PTFE bottle" but... IN THEORY.
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Jdurg
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| Quote: | Originally posted by MagicJigPipe
Wow, so many people are deadset on convincing me to reconsider. This may sound repetative but if the people who first isolated fluorine
"reconsidered" well, you know. I'm not saying I'm going to make some great discovery. But come on, SOMEONE has to do risky stuff. I will face my
fears, not run away from them. No one will convince me otherwise. I will do it when I have readied myself properly and no one will convince me to
back down. And really this is more about the production and safe handeling of fluorine than it is PTFE.
And I know fluorine is more dangerous than HF and how it reacts with various substances. I thought I made that clear. I was simply explaining a
misguided fear that I have.
And in response to Jdurg's post: Yes, the fluorine/HF reacting with the calcium in one's bloodstream and causing heart failure (among other things)
would be my greatest fear.
And, yes Ozone, PE + F2 is extremely energetic which is why it must be controlled and diluted. |
Well, when they first isolated fluorine the exact "nastyness" of the element wasn't fully known. As a result, they didn't really think that the
element was as nasty as it really is. Sometimes ignorance can be far more dangerous than riskyness.
Just look at radiation. When radiation was first discovered they thought it was the next greatest thing and wasn't dangerous at all. Unlike
fluorine, however, the nasty results take a lot longer to show up.
\"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists of the unmistakable scent of broccoli, and usually
requires wiping afterwards.\"
http://maddox.xmission.com. |
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not_important
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| Quote: | Originally posted by MagicJigPipe
So, in theory, could one use a motor oil bottle to store HF in? Yes, yes, yes I know. "Go buy a PTFE bottle" but... IN THEORY.
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Yes, but ordinary HDPE is resistant to aqueous HF for temperatures up to at least 60 C. Remember that in the old days HF was stored in gutta-percha
or wax-coated glass bottles. Paraffin wax is very much similar to polyethylene, while gutta-percha is a poly-isoprene and can be considered an
isomer of natural rubber.
http://pt.rexnord.com/products/guards/orange_peel_guards/hdp...
Porous HDPE makes a good filter for acidic fluoride solutions, useful when making fluoroborates.
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