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angelhair
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Very old Ethyl Ether
I have a ten year old bottle of ethyl ether that has never been opened, never been taken out of the box, never seen the light of day. I want to open
it. Would you open it?
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Sauron
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You are concerned about peroxide formation being present.
Treat the Et20 with anhydrous KOH pellets.
No more peroxides, if any were present. Store it over a few pellets, in a light-tight air-tight container in a cool place.
[Edited on 20-4-2008 by Sauron]
Sic gorgeamus a los subjectatus nunc.
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Mr. Wizard
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Peroxides can form under the threads of the cap, and explode when you open it. Satisfy your curiosity by taking some KI starch paper and moistening
it with 1 M HCl and touching it to the thread area. A big blue dark spot means peroxides or at least some sort of oxidizer. The classic case of old
ether in the lab = boom and fire. I wouldn't open it if it's very old.
http://ehs.ucdavis.edu/sftynet/sn-23.cfm
added link to safety info
[Edited on by Mr. Wizard]
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Sauron
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The ether (and THF) cans I recall had no threads for exactly that reason. Even the 5 liter cans had small (3/8" or so) sealed necks with a snap cap
over. Good practice was to procure sizes convenient to use in one go. Bad practice was to return a partially emptied tin to the shelf. VERY BAD
practice was/is to return an almost empty tin to the shelf.
If this container is small, then take the advice and dispose of it.
Small = 1 L or less.
If it's 5 L, then maybe it is worth trying to figure out a protocol to open it, treat for peroxides, and rebottle.
But, in even of a worst case, which explosion and fire would you rather be in?
Sic gorgeamus a los subjectatus nunc.
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smuv
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I think you are fine. To form peroxides ether needs oxygen; the very very small amount of headspace above the ether does not provide enough oxygen to
produce much peroxides (assuming the manufacturer did not store the ether under nitrogen as is common). Maybe be careful when you are opening it and
test it with KI or similar but if they have never been oppened I would not worry too much.
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YT2095
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Personally I wouldn`t touch this thing, and get it disposed of professionally.
it`s not a risk I would take.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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BromicAcid
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Big question is the container, is it the standard metal container? Usually those are used because they help inhibit peroxide formation. If the seal
is still intact, there are no signs of rust or corrosion, and everything looks fine I don't see a big risk in opening it. Usually in my experience
the peroxides are in the bottles that have been opened and improperly stored though it is possible for them to be present in maufacturer sealed
bottles it usually takes a long time for them to accumulate to any significant degree.
If you are really worried about taking off the cap and unscrewing the threads to test for peroxides, gently flip the can over and take a bottle opener
to the bottom and puncture it then test for peroxides through that hole. You will ruin the can but that is the standard way to do it where I came
from.
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Nick F
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1L of ether: £5
Damage caused by raging inferno: more, + death.
Well, that's just the way I see this.
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BromicAcid
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It is quite the inferno too, I wonder if there is a movie on YouTube or something for it, I once saw a can of diethyl ether explode in a safety video
and it was pretty impressive. Aditionally I had one explode from peroxides myself, thankfully all the ether was drained out of it at the time, still
was impressive though.
I just hardly consider 10 years to be any considerable length of time for an unopened manufacturers bottle.
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Sauron
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Overall I agree, but I think that if is a larger can, unopened, intact then it is worth thinking about how the contents can be accessed, tested,
transferred, de-poroxided if necessary and repacked (or used) all under conditions that offer minimal, acceptable levels of hazard.
1. What is the size of the can (volume ether?) If 1 L I'd say, dispose of it.
2. How about making a small puncture for a syringe entry at a point unlikely to be a peroxide buildup point? Remove an aliquot, test with
starch-iodide paper. If positive, dispose of it. If not, open it. Purify by standard methods and repackage preferably under N2 or Ar. (Small aerosol
cans of inert gas are sold for preserving wines after opening. Check vintners.)
The above is just a suggestion for a protocol.
3. Describe the cap. Screw cap or sealed tin? If former, do not open screw cap till contents have been tested.
Sic gorgeamus a los subjectatus nunc.
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Nick F
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"but I think that if is a larger can"
I just think that any can of old ether has the potential to really ruin your week. If you have any doubt, then why not just buy more?!
I don't know if the dangers of old ether are exagerrated or not, but if there's a risk which can be so easily avoided...
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evil_lurker
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| Quote: | Originally posted by Nick F
"but I think that if is a larger can"
I just think that any can of old ether has the potential to really ruin your week. If you have any doubt, then why not just buy more?!
I don't know if the dangers of old ether are exagerrated or not, but if there's a risk which can be so easily avoided... |
I've had some unstabilized ether at room temp with a little bit of water and some "head space" in a clear bottle and it hit 25ppm within a few days
according to the test strips I was using at the time.
But, some other ether, left in the fridge for a month had no detectable amounts of peroxide.
So its a crap shoot.
But, I tend to agree with the other posters. A bottle of ether is not worth a trip to the ER or worse, lost body parts.
Dispose of it properly.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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S.C. Wack
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Does anyone have an actual documented example of ethyl ether exploding upon opening, not heresay?
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woelen
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I'm also quite reluctant to believe that diethyl ether is that bad. Over here in NL it is an OTC chemical, and it can be purchased in many drugstores.
It is used for degreasing all kinds of things, as a much-less toxic alternative to volatile chlorinated hydrocarbons which were used till the mid 80's
of the previous century. If there even were only ONE explosion of an ether bottle upon opening, then the product would be taken from the shelves
immediately. And I am 100% sure, that 99.9% of the people, who buy this ether, never ever have heard of the peroxide risk (although it is mentioned on
the bottle), otherwise they would not want it anymore, given all the chemophobia of the moment.
I do believe though, that the product in NL is stabilized with some other volatile agent (I do not know what). This stabilizer, however, does not
affect normal usage of the ether, no residue is left, when the liquid evaporates.
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Nicodem
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Ethyl ether peroxide is liquid and volatile. I can't imagine such a scenario where friction from opening a screwcap would cause it to blow up.
I also find it strangely suspicious that the ether peroxide scareshit is only mediated by propaganda and that is localized to some countries only. Why
would ethers be more dangerous in one country than the others? And why the scientific community does not take the incredible dangers of ethers
seriously if it is really such a big deal? The only time you hear about dangers of peroxides in academic articles is in the green chemistry
ideological papers where the use of a different solvent is being proposed for an old method (and a couple of lab manuals and old papers from the time
when oxidation inhibitors were not added to diethyl ether).
I have heard of ethers exploding but it was because of vapors ignited by a spark or palladium, or for example working up reaction mixtures of THF with
certain oxidizers like H2O2 causing terrible runaways resulting in serious injury. Yet, I never heard of ethers exploding due to their build up
peroxide levels. Them blowing up during distillations is only possible with Et2O since other ethers have a high enough bp for the peroxides to
decompose before concentrating (unless vacuum is used).
Throwing away an unopened bottle of ether just because of propaganda sounds a bit strange, especially considering that oxidation inhibitors are added
to such solvents. I have regularly used bottles of diisopropyl ether old about 25 years and never even considered any peroxides. Actually I have only
heard about this propaganda being reproduced in this forum, never heard about it from real life.
[Edited on 21/4/2008 by Nicodem]
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Sauron
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I generally do not read anything labelled "green chemistry" as the very term sets my teeth on edge.
But the following are not propaganda:
ACS "Prudent Practices"
Various manuals on purification of reagents
Organic Synthesis
and so on.
Diethyl ether is not the worst peroxide former. THF is worse, dioxane is worse. Di-isopropyl ether is perhaps the worst.
The countermeasures are simple. The risk is real but manageable. It is not imaginary.
A German Ph.D. organicker formerly with Dynamit Nobel, and a frequent gues in my house, told me that a colleague of his lost the fingers of both hands
and hearly bled to death when a flask he was removing from a rotavap exploded due to peroxides while he was working late at night alone. Because he
had lost his fingers he could not dial the phone to summon help. He passed out on the floor. Fortunately a security guard found him in time.
You can dismiss that as anecdotal if you like. But the next time my friend is here shall I get you the name of the hapless chemist? The year that this
happened?
I trust my friend, a professional energetics chemist now in senior management, more than I trust your skepticism.
Sic gorgeamus a los subjectatus nunc.
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S.C. Wack
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You are talking about concentration of peroxide by distillation of the more volatile ether, we are talking about opening cans.
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Nicodem
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Sauron, you are misinterpreting what I said. I'm well aware of what happens when you try to distill diethyl ether full of peroxides and I even
explicitly mentioned that. If you try to rotavap it under reduced pressure, well, then so much worse since the peroxides will not decompose to any
appreciable extent and will accumulate in their entirety. Yet if you distill diisopropyl ether at normal pressure no peroxide will survive to
accumulate as the terribly explosive residue.
What I was saying is that the scare of peroxides is crap since nobody considers them as a rational subject but only as some scary ghosts out there to
kill you (obviously certain people have a lot of interest in promoting this fear and I don't mean only of the academic green chem parasites). I find
it suspiciously strange that the ones who promote this fear usually can't even draw the structure of the peroxides formed. I find the warnings in lab
manuals like Vogel's, etc. quite rational (obviously, since they were made by and for chemists), but what I read about peroxides on some less
professional hazmat homepages, and even this forum, is straight propaganda (or at least its reproduction).
PS: Ask your guest what kind of a reaction that unfortunate colleague was working up. I'm quite sure he was working up an oxidation reaction where the
peroxides formed as side reaction product rather than resulting from using old diethyl ether (unless of course if we are talking about the time before
the producers started adding 2,6-di-tert-butyl-4-methylphenol by default as the radical oxidation inhibitor). I have heard of a similar (recent) case
involving the use of THF in an oxidation that had as a result a nearly fatal injury of a poor guy rotavaping the worked up reaction (but, as I said in
my previous post, this is not related to the peroxides formed from oxygen oxidation of improperly stored ether solvents).
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Sauron
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All right, I take your point. And I agree with you.
Viz., overpriced sylvan as a replacement for THF. I bet sylvan formes peroxides, too, why wouldn't it?
I was all for opening the can, especially if it was more than a trivial size. I said so.
Now, what was the thread author going to do with the ther once opened?
Now or later he was going to use it, and having done, at some point he will want to strip it off. My point was, it would be prudent to test it for
peroxides and purify it if any are present. That's all. Destroying peroxides in ether is easy.
[Edited on 21-4-2008 by Sauron]
Sic gorgeamus a los subjectatus nunc.
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angelhair
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2.5L in a Brown bottle. Looks like this is a very polarizing issue. Half of you would take the risk. I'm still 50/50, even though it's not worth the
risk.
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panziandi
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I would open the bottle.
I believe that diethyl ether stored in an airtight amber glass bottle in the dark would carry very little risk of forming peroxides. In addition I
expect that the diethyl ether would 1) contain a stabilizer and 2) be under nitrogen or its own vapour. Also IIRC traces of ethanol in diethyl ether
also inhibits peroxide formation.
I would then test it with perhaps the iodide-starch method then treat accrodingly although I doubt it would give a strong positive result. Also if you
are not going to use the full2.5L in 6 months then perhaps consider decanting into smaller more usable bottles or flood the bottle with nitrogen or
argon after use.
I have a 500mL bottle of ether to dispense from and I went to use it about a year and half later, the bottle was two thirds filled and i tested for
peroxides, I obtained a strong positive test with iodide although I do not worry about it seeping and crystalising around the threads, since the
bottle has never been tilted. Before I use this ether I'd treat to destroy the peroxides.
Either way it would be interesting to hear if your ether was peroxide-free it would perhaps clear a lot of the confusion on how sensitive ethers arfe
to peroxide formation.
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garage chemist
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There is no danger in opening the bottle, that's for sure!
You're not taking any risk in opening it.
I would not hesistate doing so.
Ethyl ether does not form enough peroxides to be a danger without concentration by distillation.
I would even go as far as saying there's a chance it doesn't contain any peroxides. I once had a nearly empty bottle of Et2O that was over 2 years
old, and it was still peroxide free. It was ordinary reagent grade ether. The stabilizer sure does its job.
[Edited on 23-4-2008 by garage chemist]
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BromicAcid
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I have two examples of bottles of ethyl ether exploding. One is relevant and the other only slightly so.
First one, one of my ex-coworkers was working at a cleanout of a college lab down in Texas. There were bottles and cans of diethyl ether 40 years and
older in various states of ruin. Procedure for that situation was to walk them out away from people and put them behind a poly shield and hook them
to a bottle opener. Which basically seemed to be a drill with an attachement on it to hook it to a bottle cap. It looked like it was cheap but cost
a lot of money basically. It also clamped down on the bottom of the container. You stand back a distance and activate the machine with a push
button. Slowly it would unscrew the top. I used a machine a few times myself but nothing exploded. On this trip though one did explode. He
described it as spectacular, the blast shield held up and the ether pretty much exploded back and up, the field caught on fire, etc. But no one was
hurt.
Second example was at a different site where they had plenty of older cans of diethyl ether. Standard procedure is to flip them upside down carefully
then use a can opener to puncture a hole at the bottom and test for peroxides. Several of the cans were heavily rusted. Some didn't hardly test at
all, light blue on the peroxide strips. Some were blue and others black. No matter the peroxide test we would dump it into the fuels drum, I mean,
they were already open. One of those cans that turned pitch black was emptied as usual into the drum. I tossed it about 10 feet into the trash drum
and "Bang!" The bottle shot off into the air. When I looked at the bottle the metal neck of it had inverted into the bottle and the metal lid was
completely gone and the bottom ripped. It was pretty impressive.
So it can happen without concentration, just takes somewhat extreme situations. Though the care that people took for ether at my college (or lack
thereof) makes it seem like it could happen much faster if the person handling the fresh ether is a lackwit.
[Edited on 4/23/2008 by BromicAcid]
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Nicodem
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I coincidently stumbled at this paper while searching for something else and thought to post it. It is more like of historical interest, but still an
interesting read:
THE AUTOXIDATION OF ETHYL ETHER
A. M. Clover
J. Am. Chem. Soc., 44 (1922) 1107-1118.
DOI: 10.1021/ja01426a024
Attachment: The autoxidation of ethyl ether.pdf (804kB)
This file has been downloaded 1663 times
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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YT2095
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it`s interesting to note where it says that "Light isn`t indispensable".
that would explain why it can form inside tin cans too.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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