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syntelman
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When did suppliers/manufacturers start adding stabilizers to diethyl ether? And as they did unstabilized diethyl ether must (or atleast should) have
some issues with peroxide formation and their dangers. (Pure curiosity, I have no oppionion wheter opening the bottle or not is safe)
[Edited on 25-4-2008 by syntelman]
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VTchem
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I have heard that 6 months after opening and you should get rid of it or de-peroxide it. Now thats AFTER you open it and then that was not in
reference to 10 year old stuff either. I would open it with some kind of barrier between me and the bottle, I would use some kind of replacement for
my hands, I only have two and none to spare. Having an extinguisher handy would probably be a good idea too.
Thats just my opinion though, its your diethyl ether.
Go Hokies! \"If it goes \'BOOM\' I like it!\" -Me
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vulture
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I've opened ether bottles from 1993 which were already opened and used recently. No explosions. Just don't distill the stuff.
[Edited on 25-4-2008 by vulture]
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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Mr. Wizard
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Evolution in Action
borrowed from an anonymous source
Fatal Accidents: The bright side
Every day some new do-gooder is trying to save us from ourselves. We have so many laws and safety commissions to ensure our safety that it seems
nearly impossible to have an accident. The problem is that we need accidents, and lots of them.
Danger is nature's way of eliminating stupid people. Without safety, stupid people die in accidents. Since the dead don't reproduce, our species
becomes progressively more intelligent (or at least less stupid).
With safety, however well-intentioned it may be, we are devolving into half-witted mutants, because idiots, who by all rights should be dead, are
spared from their rightful early graves and are free to breed even more imbeciles.
Let's do away with safety and improve our species. Take up smoking. Jaywalk. Play with blasting caps. Swim right after a big meal. Stick something
small in your ear. Take your choice of dangerous activity and do it with gusto. Future generations will thank you.
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CyrusGrey
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| Quote: | | Let's do away with safety and improve our species. Take up smoking. Jaywalk. Play with blasting caps. Swim right after a big meal. Stick something
small in your ear. Take your choice of dangerous activity and do it with gusto. Future generations will thank you. |
Or at least tell everyone else that so my genes have less competition! 
But seriously, think of the value of your health compared to the value of a tin of ether. We need the highly intelligent people of this forum to be in
good health, and to think about sex more, so we can have at least some intelligent people in our next generation.
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Vogelzang
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https://www.hyperlab.info/inv/index.php?s=6bcf9808b6dd476be3...
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Jdurg
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I can tell you that Ether itself has a pretty invisible flame. I had a flash fire with diethyl ether take away my eyebrows for a good long while.
(Reason #1 why you don't smoke a cigarette after organic lab where ether was spilled on your jacket).
\"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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Klute
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First hand experience:
A 2.5L amber bottle of THF (SDS, stabilized with 0.025% BHT), opened over a year ago, over 3/4 full and keep in the dark at room temp (15-25°C),
without any inert atmosphere, but with a few coils of copper added, proved to give a negative test with KI/Starch paper, moistened with water after a
minute, or acidified with a drop of GAA before adding the drop of THF.
And THF is said to be more suceptible at forming peroxides than diethyl ether is 
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panziandi
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Just thought I'd add this post to this thread to save opening another.
I use THF way more than diethyl ether and never have issues with the peroxide, but I found an old bottle of diethyl ether in my cupboard. It's 500mL
bottle perhaps 400mLs left. It is LR 98% and i held it up to the light and noticed very little tiny (not lots mind) of crystaline precipitate. Not
sure if this ppt is a peroxide or if it's just an impurity. I'm guessing here but I likely purchased it about 2 yrs ago. Now it does give a positive
test with KI, but i don't wanna loose it  ... so I am thinking of shaking 100mL
portions with acid ferrous sulphate, drying with CaCl2, then with Na wire and storing in smaller bottles over maybe Cu wire, Na wire or hydroquinone.
Can I have peoples thoughts please? I know that hydroperoxides are removed by FeSO4 but IIRC dialkyl peroxides aren't, would this not be worth it?
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Klute
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I should think FeSO4 would be perfectly suitable, bisulfite is another option too.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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smuv
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Peroxides of diethyl ether are oily liquids.
"Titanium tetrachloride…You sly temptress." --Walter Bishop
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panziandi
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Yes, I am currently shaking it with FeSO4... It's just I never noticed these crystals in the bottom of the bottle before! As I hardly use diethyl
ether anymore (THF is my friend ) I'm going to divide it into smaller bottles I
think. Would you suggest storing it over Cu wire, Na, NaK, NaOH or KOH etc? Which do people find the best here?
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Klute
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I personally keep my recycled ethers (THF mainly) over a few Cu shots and with a dash of hydroquinone. KOH makes the ether all opaque with fine
precipitate, I only keep it over KOH prior to drying/distilling over NaH.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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tapira1
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KOH in Et2O
I suppose that your fine precipitate formed when you drop some KOH into Et2O is due to attack of the KOH to the glass of the bottle. These bottles are
usually type III or IV of glass (very likely to be attacked by alkalis). KOH does not prevent formation of peroxides in Et2O;on the contrary,
attending to the reaction mechanism, it should help their formation (besides it is regular practice to store ether like solvents over KOH before
distillation to produce the anhydrous grade solvent.
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Klute
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No, no definitively from the KOH as it forms over an hour or so and the glass (Duran bottles) is intact after. I don't think the THF contains much
water, it isn't anhydrous grade but not technical either... And only rarely opened.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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tapira1
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Et2O stabilization
THF is stabilized with phenolic-type compounds, which are picked up by the KOH when you store the solvent before distillation, but ether usually has
some EtOH for stabilization; I don't think "NaEtO" is formed and conveys turbidity to the Et2O.
BtW: Have you tried to "isolate" this white stuff and get something like a melting point? Do you know if, when isolated, is hygroscopic? This may tell
you something about the nature of this. I cannot figure out what else can it be. Et2O is "sulfuric ether" because it is usually manufactured by
dehydration of EtOH.
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Klute
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Well, the amount of precipitate formed when adding KOH to THF is pretty large compared to the <5ppm BHT present... I will take a picture next
time.
Concerning the white solids in Et2O, I'm sure I have been told to be on the look out for traces of white solids on th erim of old empty bottles, as
the remaining ether evaporates out..Are all possible Et2O peroxides oils?
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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tapira1
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Et2O
Not in my opinion; as far as I know, Et2O peroxides are liquids (oily). But I have where to find out for sure... Will see next Monday.
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panziandi
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I know the usual peroxides are oily but these peroxides are polymeric so in heavily peroxidised material I would imagine they would crystalise I also
seem to recall hearing that they are not that soluble in ether! Although I do not recall where I read or heard that. My plan is this currently half
way through it:
Ether 115mL shaken with FeSO4 5g/25mL with H2SO4 added. Aqueous layer removed, saline wash. Ether dried with CaCl2 or Na2SO4. Ether decanted and dried
with alkali-metal dessicant (I have not decided which), bottle into 100mL bottle purged with argon and stored over either Cu wire or Na.
The remainder of the bottle I will repeat as above but likely will store some with hydroquinone or an alcohol perhaps?!
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Formatik
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| Quote: | | Originally posted by Klute Concerning the white solids in Et2O, I'm sure I have been told to be on the look out for traces of white solids on
th erim of old empty bottles, as the remaining ether evaporates out..Are all possible Et2O peroxides oils? |
The ether autoxidation is as shown in the diagram below as from the reference: Modellversuche zur Autoxydation der Äther in Angewandte Chemie
49(5):101-103.
Oxidized diethyl ether may contain H2O2 and acetaldehyde and their accumulation products: oxyethyl hydroperoxide CH3.CH(OH).OOH or dioxyethyl
peroxide, CH3.CHOH.OO.CHOH.CH3, some ethanol, and a small amount of AcOH.
The intermediate peroxide, the hydroperoxy diethyl ether, CH3.CH.(OOH)OC2H5 is a colorless, inviscid oil of a pleasent odor. This deflagrates weakly
when heated forming an acidic fog, which smells like acetic acid. Barely sol in water, easily soluble in almost all organic solvents. Decomposed by
NaOH soln or ferrosulfate.
The polymeric ethylidene peroxide [CH3.(CH-)OO-]x, is a viscous liquid similar to glycerin in consistency. It is very friction sensitive and
exceedingly explosive. It also has a very high brisance, 4 mg of it was enough that during a micro-C-H-determination it blew the "Verbrennungsrohr"
(tube for determination) to pieces.
But the same authors of the above paper, also wrote in Ber. 1939, 72, 1933 detailed Bayer and Villiger who made an oil from H2O2, acetaldehyde, and
H2SO4, which after heated and cooled gave an exceedingly explosive crystalline mass which they called ethylidene peroxide*, and wasn't investigated
further due to its dangerous nature. The authors then suspect that their crystal comprised of mainly dimeric, next to polymeric ethylidene peroxides.
The dimer has an acetaldehyde-like stench, and has a very high vapor pressure. It is insoluble in water, but soluble in most organic solvents, and
pretty stable towards hydrolysis. They say the polymer decomposes in the heat, to depolymerise to the volatile dimer. Usually in a destillation of
diethyl ether where explosions have resulted, it is the polymeric which is responsible, on gentle heating this compound can depolymerise but the
authors above have had quite a few detonations in those procedures.
*But in the gesammelte Werke, Bayer &c., call the oil diacetaldehyde peroxide hydrate, and the crystals diacetaldehyde diperoxide. Bayer &c.
must have also had some real bitter experiences with it, to have just quit analysing it. This is a very dangerous compound, also about 110% as strong
as TNT following the peroxy aldehydes thread.
[Edited on 7-9-2008 by Schockwave]
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tapira1
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Et2O peroxides
Contrary to what I was told during years, yesterday night and today I am learning about the instability of ether peroxides against Na/KOH. It is good
to know this. However, the mistery of the solids formed is still around.
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smuv
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Isopropyl ether peroxides are solid...I think it has just been a confusion over the years. If your ether is stabilized and tightly caped; you will
not get significant peroxide formation. In order for peroxides to form there needs to be oxygen present and the amount of oxygen in the head space
above the liquid is trivial.
Like Klute I store recycled ether over copper wire. If I have had unstabalized ether sitting around for a while before distilling/evaporating to
dryness, I allow it to stand over a sodium bisulphite or metabisulphite solution for a few hours.
Also amber glass bottles on their own are probably effective inhibitors although I don't use them as much as I probably should.
"Titanium tetrachloride…You sly temptress." --Walter Bishop
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Saber
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When you add a NaOH to peroxide conatining ether it will precipitate the hydroperoxide with the ether. This is much less explsoive however still
dangerous.
It should be removed by filtration.
[Edited on 7-9-2008 by Saber]
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Klute
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I remember certain notes going around about drying THF with KOH being an explosion hazard if peroxides were not detroyed before adding the KOH.
Apparently, explosions happened enough times for people to get concerned about it and start warning other labs about this..
http://www.orglist.net/archive/2003/0083.html
Hum, can't find the article/note I'm taling about...
Here is a very complete document on peroxide-forming chemicals and their handling (in French though ):
http://www.inrs.fr/INRS-PUB/inrs01.nsf/inrs01_catalog_view_v...
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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matei
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From "Inorganic Syntheses", Vol. XII:
Purification of Tetrahydrofuran
It has been reported that serious explosions may occur when
impure tetrahydrofuran is treated with solid potassium hydroxide or with concentrated aqueous potassium hydroxide, as has been recommended widely for
the purification of tetrahydrofuran; see Organic Syntheses, Coll. 4,* 474, 792 (1963); 40, 94 (1960). There is evidence that the presence of peroxides
in the tetrahydrofuran being purified was causal. It is strongly recommended, therefore, that this method not be used to dry tetrahydrofuran, if the
presence of peroxides is indicated by a qualitative or quantitative test with acidic aqueous iodide solution. Traces of peroxide can be removed by
treatment with copper (I) chloride (cuprous chloride) see Organic Syntheses, 46, 57 (1965). The safety of this operation should be checked first on a
small scale (1-5 ml.). It is recommended that tetrahydrofuran containing larger than trace amounts of
peroxides be discarded by flushing down a drain with tap water. It must be kept in mind that mixtures of tetrahydrofuran vapor and air are easily
ignitable and explosive; purification is best carried out in a hood which is well exhausted and which does not contain an ignition source.
The best procedure for drying tetrahydrofuran appears to be
distillation (under nitrogen) from lithium aluminum hydride.
This operation should not be attempted until it is ascertained
that the tetrahydrofuran is peroxide-free and also not grossly
wet. A small-scale test can be carried out in which a small
amount of lithium aluminum hydride is added to ca. 1 ml. of the tetrahydrofuran to determine whether a larger-scale drying operation with lithium
aluminum hydride would be too vigorous for safe operation. Tetrahydrofuran so purified rapidly absorbs both oxygen and moisture from air. If not used
immediately, the purified solvent should be kept under nitrogen in a bottle labeled with the date of purification. Storage for more than a few days is
not advised unless 0.025% of 2,6-di-t-butyl-4-methylphenol is added as an antioxidant. There are no indications that peroxide-free, but
moisturecontaining, tetrahydrofuran cannot safely be predried over potassium hydroxide. However, even this operation should be attempted only after a
test-tube-scale experiment to make sure that a vigorous reaction does not occur.
A peroxide-free grade of anhydrous tetrahydrofuran (stabilized by 0.025 % of 2,6-di-t-butyl-4-methylphenol)i n 1-lb. bottles is available currently
(1970) from Fisher Scientific Co. This product as obtained from freshly opened bottles has been found to be suitable for reactions, such as the
formation of Grignard reagents, in which purity of solvent is critical (Du Pont Company, unpublished observations). It is standard practice in at
least one laboratory to use only tetrahydrofuran (Fisher) from freshly opened bottles and to discard whatever material is not used within 2 to 3 days.
[Edited on 7-9-2008 by matei]
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