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Sulaiman
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How hazardous is fluorine chemistry?
I'm comfortable with iodine, bromine, chlorine and most of their compounds,
and I'm considering doing a little fluorine chemistry,
which I have until now avoided.
So I want to ask members that have actual physical experience with fluorine and its compounds;
How much more hazardous is fluorine than chlorine?
CAUTION : Hobby Chemist, not Professional or even Amateur
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charley1957
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Sulaiman, I haven’t personally done any fluorine chemistry, but I have spent the past several years reading up on it, researching, and building a HF
distillation unit. I have a stack of research papers, methods, diagrams, and information that I would be happy to scan and send you if you’d like.
I also have 98% acid grade fluorspar, a bunch of it, and would be glad to send you some if you need. U2U me for more information. I know that the
discussion of fluorine or even HF in this forum has been a sore spot in the past. Personally I don’t see where working with either of these
chemicals with lots of research and preparation is any different than working with dozens of other things some of us routinely do which I feel are
more dangerous. There are those here who feel like it is an instant death sentence, however. Anyway, there’s the offer.
You can’t claim you drank all day if you didn’t start early in the morning.
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Admagistr
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The fluoride anion binds the calcium cation Ca2+ and CaF2 is insoluble and the calcium bound in this way is definitely lost for the organism! So
elemental F and most of its compounds, especially the soluble ones, are highly toxic! It is much worse than the other halogens, although bromine is
also quite neurotoxic...Fluorine is also the most reactive element hence its additional risk...
[Edited on 14-2-2024 by Admagistr]
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Texium
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Fluorine chemistry is a "sore spot" both on this forum and among chemists in general for good reason. Spill a few mL of conc. HCl on your hand, you
rinse it off and go on with your day. Spill a few mL of conc. HF on your hand, and you could die if it's not immediately treated. If it doesn't kill
you, it'll almost certainly give you excruciating pain. That's not an alarmist exaggeration, it's a fact. If enough fluoride ions get into your
bloodstream, it can shut down the calcium ion channels that keep your heart beating.
Quote: Originally posted by charley1957  | | Personally I don’t see where working with either of these chemicals with lots of research and preparation is any different than working with dozens
of other things some of us routinely do which I feel are more dangerous. |
While this may be true (though I'd
be curious to hear what routine things you think are more dangerous), the way I see it is, why risk it when there's plenty of interesting chemistry
that can be done without fluorine?
If you still insist on pursuing fluorine chemistry though, don't even think about doing it without having calcium gluconate gel close at hand. Wear
good safety goggles, gloves, and a lab coat. Work on small scales to avoid the possibility of a catastrophic accident that could kill you. Don't work
alone.
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Texium
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Thread Moved
14-2-2024 at 08:20 |
bnull
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Skip it. You're a "Hobby Chemist, not Professional or even Amateur". Even the professionals avoid it. The bad reputation F has was very well earned.
It's a little hard to see someone who had "actual physical experience with fluorine and its compounds". Or someone who is still healthy with all the
fingers still attached. Remember what John D. Clark wrote in Ignition! about ClF3:
| Quote: | | All this sounds fairly academic and innocuous, but when it is translated into the problem of handling the stuff, the results are horrendous.
It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no
ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention
asbestos, sand, and water--with which it reacts explosively. It can be kept in some of the ordinary structural metals--steel, copper, aluminum,
etc.--because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on
aluminum keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is
confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running
shoes. |
If the tales of mishaps didn't scare you enough, read "Toxic properties of inorganic fluorine compounds" by R. Y. Eager.
And if, after all the gruesome details, you still want to mess with fluorine reactions (and have written your will, don't care about amputations or a
slow, painful death, don't intend to have kids and such), do it in a non-DIY glove box. Preferably a glove box distant a couple of miles away from
you.
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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Sulaiman
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| Quote: Originally posted by Texium | | ...If you still insist on pursuing fluorine chemistry though, don't even think about doing it without having calcium gluconate gel close at hand. Wear
good safety goggles, gloves, and a lab coat. Work on small scales to avoid the possibility of a catastrophic accident that could kill you. Don't work
alone. |
Although I agree with all of the above,
I work alone
because of the people that I know,
none are interested in chemistry,
and certainly none would be competent enough to rescue me.
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Texium
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Then don't do it. If you can't call out to someone nearby to get you to the emergency room as you're flailing around on the floor with muscle spasms
from hypocalcemia, then you shouldn't take the risk.
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Sulaiman
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OK
Postponed indefinitely
Thanks
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DraconicAcid
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Good idea.
(I seem to recall that it's advised not to wear a pair of gloves, but you put on one pair of gloves, cover them with calcium--based gel, and then put
on another pair of gloves on top of the first.)
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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clearly_not_atara
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It's a pretty broad question, isn't it? As Texium emphasized, HF is extremely dangerous. Many fluorides attack glass, which also creates a barrier to
working with them.
But not all sources of fluoride are as dangerous as HF. Hydrogen fluoride, pKa 3.2, crosses the skin as a neutral molecule. However, ionized fluoride
does not have this property. Fluoride salts in neutral or alkaline solution are much less dangerous.
Unfortunately, HF is the entry point to most of the interesting fluorine chemistry! So there's not a whole lot that can be done safely. There are a
few interesting applications of CsF and a lot of things that you can do with AgF, although caution is advised since the organic halogen exchange with
AgF can be very exothermic. The requirement for large quantities of silver limits what you can do, though.
I have considered the preparation of certain 2-fluoroethyl compounds with AgF. Otherwise I think of fluoride as something to be avoided.
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woelen
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I personally have done a few experiments with 48% HF, but I did not feel comfortable at all while working with this.
I know about the extreme risk and the toxic effects. It is much more dangerous than e.g. cyanides or even arsenic. Its effects are extreme. Have a
look at internet, when you search for hydrofluoric acid wounds. If you see that, then you understand why I am so reluctant to experiment with this
acid.
Working with fluoride salts is less dangerous (e.g. NaF, KHF2, NH4HF2), but still, be very careful with them and do not allow the liquids to touch
your skin!
Some fluorine-containing salts can be handled in a somewhat more relaxed way. An example is HBF4 and salts of that. The BF4(-) ion is sufficiently
stable to stay around in aqueous solution with only little hydrolysis to HF and boric acid. Salts of this ion are even more stable (e.g. NaBF4,
Co(BF4)2, Cu(BF4)2, NH4BF4). The BF4(-) ion is quite inert, and a good counter-ion if you want to experiment with metal complexes. But I prefer
ClO4(-) for that purpose, I still feel not entirely comfotable with the fluorine in the BF4(-) ion. It can hydrolyze to HF, especially on long
standing in lower concentrations at low pH.
One of the experiments I did with flouride is the following: https://woelen.homescience.net/science/chem/exps/KMnO4+NaF+H...
Another experiment with fluoride: https://woelen.homescience.net/science/chem/riddles/titanium...
As you can see, only small quantities were involved and the starting point is NaF. The fluoride and HF is very dilute, but sufficiently concentrated
to cause severe issues if your skin is exposed to this!
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Sulaiman
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Side note... just checked online shopping here,
1M (2%) HF 1litre USD10.45 equivalent...including shipping.
All I'd have to do is distill it 
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Fleaker
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At work, I once had to deal with anhydrous HF and TaF5 together. It was not a fun experience. Suffice it to say, the combination is extremely
aggressive to polymeric materials and chews them up.
HF here in the USA, by the 1000 liter tote--with no valve allowed--about $1.40/lb at 48-49 wt %.
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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Twospoons
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Pickling paste for stainless steel welding contains up to 5% HF. I wonder how many welders know just how risky that stuff is? How many would have
calcium gluconate gel on hand?
Helicopter: "helico" -> spiral, "pter" -> with wings
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Bedlasky
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There are some experiments with fluorides which can be done relatively safely. Lanthanides make beautiful insoluble fluorides. You can try making some
stable fluoro complexes like [BF4]-, [SiF4]2-, [AlF6]3- etc. Hexafluoroaluminates have pretty low solubility, even Na or K salts. You can decolorize
Fe(III)-SCN- complex with fluoride. You can use fluorides to get dissolve some very inert metals like Ti, Zr, Hf, Nb, Ta (use fumehood or work in well
ventileted are, because you may need to heat these solutions if needed). Or you can try conductometric titration of fluoride with CaCl2. Just work in
small scale and be careful. You don't need HF for these experiments at all, just some soluble fluoride (NaF, KF, NH4F etc.)
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BromicAcid
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Fluorine chemistry can be dangerous. The old standby to have on hand is calcium gluconate. But I posted in a different thread before that became
common it was just magnesium sulfate paste in ethanol (you'd have to find the thread to be sure) or something that was pretty accessible.
I've ended up working with quite a bit of fluorine chemistry over the years. There are precautions to take for sure and at one point I even
entertained building a fluorine cell. But there are other things we deal with that are quite dangerous as well. I would hardly say the danger is in
a league of its own but it does pose some unique hazards you need to consider whenever you experiment.
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chornedsnorkack
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| Quote: Originally posted by woelen | I personally have done a few experiments with 48% HF, but I did not feel comfortable at all while working with this.
I know about the extreme risk and the toxic effects. It is much more dangerous than e.g. cyanides or even arsenic.
|
What is so bad about arsenic?
HF and HCN seem to have some of the similar hazards - both are low boiling (HF at 19,5 Celsius, HCN at 25,5 Celsius), weak acids, can pass through
intact skin. Both are weak acids so you can suppress volatilization (and skin absorption?) by keeping solutions neutral/basic. HF is stronger acid
than HCN, so easier to keep in neutral or mildly basic solutions.
In contrast, much of the As compounds is not so volatile. OK, arsine and halides are, but it seems that HAsO2 does not tend to volatilize as much?
Does this HF also etch your glassware? You don´t seem to mention it.
Also, are there any nice colour reactions for low concentrations of HF?
[Edited on 15-2-2024 by chornedsnorkack]
[Edited on 15-2-2024 by chornedsnorkack]
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unionised
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There's a plant which makes 2 fluoroethyl compounds.
https://en.wikipedia.org/wiki/Dichapetalum_cymosum
"commonly known as gifblaar from Afrikaans, "
"gifblaar " means "poison leaf.
So this stuff- which is toxic enough for a plant to be named after it- is one of the less dangerous fluorine compounds...
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Sulaiman
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Thanks, good to know,
Where can I get some?
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EF2000
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Gifblaar contains sodium fluoroacetate, the infamous "compound 1080".
There's also a lot of fluoroacetate-containing plants in Australia, mainly in genus Gastrolobium, also called "poison pea" or "poison brush",
or just "poison".
Though, if you get to Australia, much easier is to extract 1080 from poison baits used for control of invasive species.
Wroom wroom
"The practice of pouring yourself alcohol from a rocket fuel tank is to be strongly condemned encouraged"
-R-1 User's Guide
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clearly_not_atara
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Fluoroacetate is special, you know that. It specifically inactivates aconitase. Much more toxic than 3-fluoropropionate for example, and also more
toxic than difluoroacetate or trifluoroacetate. It's also technically not a fluoroethyl compound if we're being pedantic.
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unionised
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No, but it's the metabolic endpoint of some fluoroethyl compounds...
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Keras
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I have a 1L bottle of 60% HF on my shelves. Never opened it. I have a tube of calcium gluconate gel at hand, but up to know, I didn't dare opening the
bottle.
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chornedsnorkack
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Some instructive text from professionals:
https://ehs.wisc.edu/wp-content/uploads/sites/1408/2020/08/S...
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Precipitates
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| Quote: Originally posted by Sulaiman | Side note... just checked online shopping here,
1M (2%) HF 1litre USD10.45 equivalent...including shipping.
All I'd have to do is distill it |
70% HF is available here for around 6 USD per litre, which is kind of terrifying
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