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Author: Subject: Inert atmosphere, which is best?
antibody
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[*] posted on 10-5-2011 at 06:12
Inert atmosphere, which is best?


Hi
Ab2 is hoping some of the local hazards might be able to weigh in on this subject. Ab2 needs an inert atmosphere for some alkylation work using STAB and ZnBH4, but at the same time would like use the inert atmosphere to blanket bottles of THF and ethers etc. that have been opened.


Ab2 understands Argon is denser and less reactive than nitrogen, and perhaps more expensive too.

Is argon or nitrogen is the best way to go? Is there an overwhelming reason why one would be preferred over the other? Any words from the wise would be appreciated.

Also wondering what would be the best regulator for the job. One that would allow a very slow steady trickle of gas. Any suggestions. One supplier Ab2 spoke with suggested a regulator with a needle valve.

Thanks


[Edited on 10-5-2011 by antibody]

[Edited on 10-5-2011 by antibody]
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watson.fawkes
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[*] posted on 10-5-2011 at 06:26


Who is "Ab2"?
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hissingnoise
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[*] posted on 10-5-2011 at 06:46


He's the second person to refer to himself in the third person in a week . . . l☺l

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symboom
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[*] posted on 10-5-2011 at 07:25


nitrogen or argon is fine for that purpose anything but oxygen because nitrogen does not react with those.
if you make sodium argon is better because nitrogen reacts with sodium to form sodium nitride.

as for regulators a welding supply place would help you there
small nitrogen tanks are used in paint ball
argon in arc welding
now that i think of it co2 tank should work for your purposes too.
co2 is heavier than air. dry ice is a source there.

[Edited on 10-5-2011 by symboom]
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antibody
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cool.gif posted on 10-5-2011 at 07:33


Thanks Symboom!

Quote: Originally posted by hissingnoise  
He's the second person to refer to himself in the third person in a week . . . l☺l

Actually, Ab2 has been referring to herself in third person for years, its preferable to SWIMing or FOAFing :cool:

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hissingnoise
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[*] posted on 10-5-2011 at 07:57


Wimin make the best cooks! :D

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Magpie
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[*] posted on 10-5-2011 at 08:12


A thread you may find useful:

http://www.sciencemadness.org/talk/viewthread.php?tid=10366

What's FOAFing?




The single most important condition for a successful synthesis is good mixing - Nicodem
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antibody
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[*] posted on 10-5-2011 at 08:28


Thank you magpie
that thread has lots of useful information, not the least of which being that nitrogen has the same density as air, Ab2 was under the misapprehension that it was heavier than air, very good to know.
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a_bab
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[*] posted on 10-5-2011 at 08:39


To Ab2 it could be a shock that the air contains mostly nitrogen, otherwise I can't explain such a "good to know" fact that N2 is not heavier then air.
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Bot0nist
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[*] posted on 10-5-2011 at 08:59


FOAF = Friend of a friend. Another useless acronym like SWIM meant to help anonymity and plausible deniability in the event that there posts are scrutinized by LE. I highly doubt its efficacy though.


[Edited on 10-5-2011 by Bot0nist]




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antibody
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[*] posted on 10-5-2011 at 08:59


It is a surprise a_bab. :)

to be honest, Ab2 hasn't spent much time considering the make up of air, but if nitrogen has the same density as air then how would one lay down a blanket of the gas in a bottle? wouldn't it just float away?
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[*] posted on 10-5-2011 at 09:02


Quote: Originally posted by antibody  
It is a surprise a_bab. :)

to be honest, Ab2 hasn't spent much time considering the make up of air, but if nitrogen has the same density as air then how would one lay down a blanket of the gas in a bottle? wouldn't it just float away?


If it was less dense it would. A gas of neutral buoyancy should work it the environment is still and of equal temperature.




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UKnowNotWatUDo
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[*] posted on 10-5-2011 at 09:54


Technically speaking pure nitrogen gas would have a density slightly lower than that of normal air, as the atmosphere is composed of roughly 4 parts nitrogen and 1 part oxygen. Though I doubt this would make hardly any difference.
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[*] posted on 11-5-2011 at 10:09


Is ab2 certain that an inert atmosphere is needed at all? I don't think STAB is terribly reactive towards moisture, some reports claim HCHO(aq.). Combine with moderate temperature and short reaction time, I think it's worth to risk it.

If you have the choice go for argon - cheap enough, good availability and heavier than air.

PS: divine moments of truth, right? :D
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