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Author: Subject: Storage of volatile solvents?
khourygeo77
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[*] posted on 18-3-2017 at 09:53
Storage of volatile solvents?


Hello,

I am thinking about starting work with some volatile solvents soon (36 deg C+ boiling point). However, the only problem that I am going to face will be storage conditions. I was wondering if this is possible without going for pressurized tools or other expensive stuff, but by doing it easily. (without storing in fridge or freezer).

Any ideas?
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Elemental Phosphorus
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[*] posted on 18-3-2017 at 10:44


It may be possible, depending on your ambient temperature. A media bottle, stored out of sunlight and at a low ambient temperature might work, with some venting. But you will get losses to vapor, and possibly a dangerous buildup of flammable vapor. Diethyl ether comes to mind based on your description. Really though, the best way to store any highly volatile compound is with refridgeration.
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khourygeo77
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[*] posted on 18-3-2017 at 11:34


Quote: Originally posted by Elemental Phosphorus  
It may be possible, depending on your ambient temperature. A media bottle, stored out of sunlight and at a low ambient temperature might work, with some venting. But you will get losses to vapor, and possibly a dangerous buildup of flammable vapor. Diethyl ether comes to mind based on your description. Really though, the best way to store any highly volatile compound is with refridgeration.


DCM and pentane actually.

I was thinking about storing the container in water and in the dark (water is normally lower than atmospheric temperature), then sticking a long pipe to the only opening of the container, so vapors are trapped inside the pipe and come down again...

The summer here only hits 36+ deg C a few times. At other times, temperature's average would be around 25 deg C.

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karlos³
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[*] posted on 18-3-2017 at 11:48


In which case it should be a special fridge for chemicals, since the exclusion of air inside a fridge and consequently a build-up of fumes(slower but still happening), combined with the probably not spark-resistant switches in it are dangerous on its own.
It may be better to store compounds which are highly volatile at RT, in a fridge, but one has to consider the vapour pressure too.

Edit: my post relates to Elemental Phosphorous posts, not the OP´s second post.

But for DCM, storing is less catious since it is not flammable. Just keep cool and away from light(comes in brown-glass bottles always anyway).

[Edited on 18-3-2017 by karlos³]
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Elemental Phosphorus
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[*] posted on 19-3-2017 at 04:40


You'd save yourself some solvent if you pick up a bag of ice for the water in the design you propose.
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tsathoggua1
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[*] posted on 20-3-2017 at 00:00


Thats a problem thats been irritating me. Just what plastics ARE permeable to ethers, dichlor and CHCl3, as well as C-tet.
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MrHomeScientist
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[*] posted on 20-3-2017 at 11:49


The most important thing to consider for solvent storage is the cap on the bottle. That is the only route for escape, and if it isn't sealed well fumes will leak out no matter how cold you can get it. Some solvents do just fine with normal plastic caps, but others are insidious escape artists. I've had a hell of a time finding a bottle that will store tetralin without letting vapors out. My next attempt (the 4th) will be a glass media bottle with a red, Teflon-lined cap and some PTFE thread-seal tape. If that doesn't work, I give up.
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AJKOER
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[*] posted on 22-3-2017 at 07:01


One simply/cheap/ugly idea is to invert the bottle containing the volatile substance in a small bucket with sufficient water covering the cap. Cover all a with plastic wrap to lower the evaporation rate of the water.

This should work for inert caps. Gas buildup still possible so make the cap the weakness escape route. Spillage cause by gas formation would be contained in the bucket.

An unexpected advantage is that the ominous chemical storage area now looks like a friendly plant shop;).
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macckone
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[*] posted on 22-3-2017 at 07:28


One solution I came up with for storage of volatile
compounds was to use a 12V thermoelectric ice chest.
Since there are no switches inside the ice chest and
it will keep things cold even in the event of power
failure, they work great.

https://www.amazon.com/dp/B007ZYH4BM/

You can make your own from a regular ice chest
with peltier thermoelectric coolers.

http://www.digikey.com/product-detail/en/CP30338/102-1668-ND...

* edited for formatting

[Edited on 22-3-2017 by macckone]
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Archenemy_6
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[*] posted on 22-3-2017 at 20:18


I purchased these glass bottles from Uline that seem to be pretty nice I have a few things stored in them now. I'm not sure what the seal on the cap is made of but I bought a PTFE sheet that I cut to make a seal to put in the cap if it's really volatile. I have some diethyl ether and dichloromethane in the bottles wrapped in foil stored in the freezer.
I've heard mostly to not store them in the freezer because of buildup of vapors but I can't smell any vapors coming through the caps on either bottle and the pressure in the bottle seems to hold ok. It always let's out a hiss when I open it.

Although I'm not sure if smell is the best indicator for how well a bottle seals
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Herr Haber
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[*] posted on 23-3-2017 at 04:09


And how about media bottles with caps that will withstand what you'll be storing ?

1L of DCM left in it's original HDPE bottle at room temperature was nowhere to be found when I needed it 6 months later. All evaporated...
1L of DCM in a Duran / Simax media bottle with a PTFE lined Duran cap ---> No loss at all

And what is this I read about venting solvent bottles ? Why on earth would anyone do that ?
I have a lot more solvents that will react with athmospheric O2 than solvents that will *burst* a proper bottle.
Oh wait... I cant think of a solvent that would do that ! I can think of a lot of solvents that I have seen evaporating and condescing on the interior of the bottle though.
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[*] posted on 23-3-2017 at 05:00


Quote: Originally posted by MrHomeScientist  
The most important thing to consider for solvent storage is the cap on the bottle. That is the only route for escape, and if it isn't sealed well fumes will leak out no matter how cold you can get it. Some solvents do just fine with normal plastic caps, but others are insidious escape artists. I've had a hell of a time finding a bottle that will store tetralin without letting vapors out. My next attempt (the 4th) will be a glass media bottle with a red, Teflon-lined cap and some PTFE thread-seal tape. If that doesn't work, I give up.



according to http://www.rjchase.com/ptfe_handbook.pdf
ptfe is not cross-linked so it can creep
ptfe is porous to some gases


Is ptfe a good liner for volatile solvents ?

EDIT: With these thoughts in mind, I just bought a 0.1 x 100 x 200 mm sheet of titanium to cut some cap liners and as a base for Pt foil electrodes.
http://www.ebay.co.uk/itm/0-1x100x200mm-Silver-Titanium-Foil...

I should be able to report back on the utility of Ti foil liners in a year or two :P

[Edited on 23-3-2017 by Sulaiman]




CAUTION : Hobby Chemist, not Professional or even Amateur
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khourygeo77
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[*] posted on 23-3-2017 at 12:57


Thanks guys for all your recommendations. Much appreciated
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Booze
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[*] posted on 24-3-2017 at 07:24


If you really want nothing to escape at all, or the thing you are making can escape easily, make some ampoules by putting your chemical in a test tube and use a blowtorch to seal 1 end.
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mr.crow
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[*] posted on 24-3-2017 at 19:35


My favorite storage method is a Pyrex media bottle with a GL45 cap. Get an expensive cap with a PTFE liner or entirely fluoropolymer for chemical resistance. Then wrap the cap with electrical tape. Aluminum tape (for sealing ducts) is also great for solvent vapors.

For storage I like to put the bottle into a tupperware container with a sealed lid. Put an open bottle of NaOH in the tupperware to absorb all moisture and acid fumes.




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Melgar
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[*] posted on 25-3-2017 at 13:37


Eh, just use a nice thick polyethylene cap, then put a piece of polyethylene sheet over the opening when you go to close it, and screw the cap down over that. Then just cut off any excess with scissors. Will some solvent escape? Of course, but permeability drops exponentially the thicker the cap is. If your solvent doesn't corrode metal, that's an excellent option too, since glass and metal are the two things that truly are impermeable to solvent diffusion.

Quote: Originally posted by Booze  
If you really want nothing to escape at all, or the thing you are making can escape easily, make some ampoules by putting your chemical in a test tube and use a blowtorch to seal 1 end.

For the love of God, please use disclaimers! The last thing we need is someone trying this with diethyl ether!

[Edited on 3/25/17 by Melgar]
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Booze
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[*] posted on 26-3-2017 at 13:31


You mean like "use a respirator blah blah blah"? I'm pretty sure anyone with two brain cells to rub together can figure out that sealing a tube with diethyl ether can boil some, but not a lot.
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[*] posted on 26-3-2017 at 13:35


Quote: Originally posted by Booze  
You mean like "use a respirator blah blah blah"? I'm pretty sure anyone with two brain cells to rub together can figure out that sealing a tube with diethyl ether can boil some, but not a lot.

Oh, it's flammable. I didn't realize that. Sowwy
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Elemental Phosphorus
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[*] posted on 27-3-2017 at 09:11


Usually I would use glass Boston Round bottles with tight teflon caps for a volatile solvent, especially for things like DCM and ether.
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