Quince
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Storing methylene chloride
I'm reading that polyethylene is not resistant to methylene chloride, yet the paint strippers here come in metal cans that have caps made of the
plastic. So, what gives?
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Darkblade48
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As far as I know, the paint strippers that I can get aren't dichloromethane, they just don't have that same ethereal smell when I open the bottle (not
that I particularly want to smell them).
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Quince
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It says "contains dichloromethane" and about 2/3 the volume distills off at 40*C. There's no doubt about it.
I've another problem. The gelling additive is a gooey polymer left behind after distillation. I can't for the world figure out how to get it out of
the container so I can use the can for storing the distilled methylene chloride. I don't have any other container I can use...
[Edited on 6-12-2006 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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DeAdFX
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Quince. I assume you get your Dichloromethane(DCM) from a hardware store like lowes/homedepot/etc. I recommend finding a dedicated paint store that
sells DCM. Chances are the DCM will be of higher purity. Make sure you ask for the thin wash as thick wash will contain polymers n shit. I believe
my DCM contains methanol only as the contaminate.
My DCM is stored in a plastic container. I do not know what the plastic is specifically. I would recommend using a metal can. I also recommend not
filling the can to the top(fill to 75%). Under mild temperatures(75+Fahren) my DCM bottle begins to bloat a bit.
[Edited on 6-12-2006 by DeAdFX]
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Quince
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The only polymers I found on the web specified resistant to it are some of the flourinated ones such as teflon.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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unionised
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Polythene is resistant to dcm in that it isn't destroyed by it. Unfortunately the dcm diffuses through it and escapes. The technical solution to this
is the foil-lined cap.
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unionised
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[Edited on 6-12-2006 by unionised]
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Fleaker
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Or perhaps you can use a glass bottle with a phenolic cap? On my bottle of reagent grade dichloromethane, the cap appears to be the standard phenolic
one used for things like HCl...
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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Ozone
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Yes,
But, the phenolic cap on a commercial bottle of DCM has a teflon liner (at least mine do). In general, DCM can be stored in either glass or metal.
Either way, it must be *inhibited* as with chloroform via addition of a small amount of amylene (EtOH is also used, and is most accessable). This
prevents the decomposition to yield wonderful things like phosgene.
Also, these compounds are photochemically active; storage in an amber vessel or wrapping your bottle with Al° foil is a must if it cannot be stored
in darkness.
I'm thinking, however, that more crystalline polymers, such as polypropylene would also be suitable, at least for short term storage.
The foil lined cap works well also, and Al° foil can be used in a pinch with just about any cap. Avoid stoppers (rubber) as they will swell and
perhaps slime over contaminating your solvent.
NEVER, ever let DCM come in contact with PEEK; it destroys it instantly.
FYI, never use a cheap graduated pipette to remove solvent from the bottle...The adhesive connecting the markings to the glass is dissolved.
Result--blue or green "floaties" in your DCM which is now hot-fluorescent pink under longwave UV. The floaties are *very* difficult to remove from
glass. This both sucks (in general) and screws up the validity of your work.
So, for all, a gentle reminder not to take solvent or reagent directly from the container--always dispense into a secondary container first!
Oh (aside), THF softens PE syringes...
Take care, all,
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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Quince
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| Quote: | Originally posted by unionised
Polythene is resistant to dcm in that it isn't destroyed by it. Unfortunately the dcm diffuses through it and escapes. The technical solution to this
is the foil-lined cap. |
Yes, but I can't use the can since I can't get the residue out of it. The only thing I have is high density polyethylene bottles. Are you certain
that this material will not contaminate the methylene chloride?
In http://www.simport.com/en/charts.php?PHPSESSID=b41e9a2bb531d... the resistance of HDPE to methylene chloride at 20*C is listed as 'B', which they
define as "B=Good res. little etching after 30 days exposure." That doesn't tell me whether there's any contamination of the solvent from the
plastic. Plus, I'm interested in storing for a year, not a month.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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unionised
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I'm pretty certain that the DCM will diffuse through the polethylene bottles at a very annoying rate. A glass bottle (brown glasss is good) with a
plastic cap lined wth enough foil that the DCM never contacts the plastic will do for a reasonable while.
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Quince
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Ugh... forgot to wrap the silicone ring on the thermometer hole of the still head in PTFE tape... now the DCM has eroded it badly. Are there any
non-fluorinated polymers that are resistant and relatively impermeable?
[Edited on 11-12-2006 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Maya
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a wood cork? old school
personally, I would use all glass , metal or teflon in that order of preference or a mix thereof
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imandroid
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Chem Storage Containers
Ghetto it with a dark colored glass Magnum Champagne Bottle plugged with a #1 hard rubber stopper wrapped up completely and wrapped again completely
over the first wrapping in teflon tape...this is economically practical beings the bottles can be found by the truckloads behind restaurants, bars,
night clubs, etc.. for free... a roll of teflon tape can be purchased with some loose pocket change and rubber stoppers ordered in bulk for around $10
for a hundred mixed sizes (meaning 40% + are #1's.. heh.... usually add a tight wrap of nylon tape to the rim of the bottle opening after the plug
is fastened for good measure on items that won't be used daily.. just to insure the stopper stays in place and sealed.. then labelled and shelved in
the storage cooler..
..yeah, whatever.. I\'m just Android
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not_important
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| Quote: | Originally posted by Quince
I've another problem. The gelling additive is a gooey polymer left behind after distillation. I can't for the world figure out how to get it out of
the container so I can use the can for storing the distilled methylene chloride. I don't have any other container I can use...
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Sounds like you're distilling out of the container, so this might not work for you, but ...
When I needed some DCM and couldn't find a local supply of the pure solvent, I too went for paint stripper. I mixed it with an equal amout of kerosene
and distilled off the DCM. Then I heated the flask hotter, and poured off the contents into a empty paint can. I then added fresh kerosene to the
flask, heated it, and poured that into the paint can; that seemed to leave the flask pretty clean, a couple of rinses with little acetone finished the
job.
Kerosene isn't a great solvent, but when it's hot a lot of stuff dissolves in it to some degree. Other high boiling solvents that don't form
azeotropes with DMC should work also. Just remember to be careful when pouring out the hot solvent, no flames or sparks!
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MagicJigPipe
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Sorry to bring up such an old thread but I was wondering... Since gas tanks (you know, the red plastic ones that replaced "jerry cans") are
supposedly coated with a fluorpolymer on the inside they should be okay for storing 35% sulfuric acid or toluene (surely because the components of
gasoline don't dissolve it), right? Well, of course, IF they really are coated.
I noticed that the "coating" on the inside of the "can" is different and has sort of a translucent look and feels more smooth than the outside.
The reason I ask is because I had to dump some toluene and sulfuric acid into two 5 gallon plastic gas cans because they were leaking. It was the
best I could do on such short notice and I heard they were fluorinated on the inside, hence my decision.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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Phosphor-ing
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I don't foresee a problem with toluene as it is a component of gasoline anyway. The Sulfuric acid is listed as conditionally resistant @30%
concentration here. Probably means don't let it get hot.
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Fyndium
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I have a bottle of chloroform that has 2013 exp date. Been in darkness at varying temps (-25 to +35) in original amber bottle, full and closed. Should
there be a reason for worry? I used it already with no issues, and it retained a bad smell although I used respirator.
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itsallgoodjames
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Quote: Originally posted by Fyndium  | | I have a bottle of chloroform that has 2013 exp date. Been in darkness at varying temps (-25 to +35) in original amber bottle, full and closed. Should
there be a reason for worry? I used it already with no issues, and it retained a bad smell although I used respirator. |
Is it stabilized with some sort of alcohol? If so, neutralize the HCl that has built up with some bicarb, then distill. Even if it wasn't
stabilized, I wouldn't be worried, as you said it was full and in the amber glass bottle. Just neutralize any phosgene that may have built up,
distill, and add some sort of alcohol to prevent any phosgene from forming in the future.
Nuclear physics is neat. It's a shame it's so regulated...
Now that I think about it, that's probably a good thing. Still annoying though.
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