From: "Singh,Shailendra" <singhss**At_Symbol_Here**EHS.UFL.EDU>
Subject: Re: [DCHAS-L] Pyrophorics
Date: Fri, 25 Sep 2015 16:58:32 +0000
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: 917e46e9911b40c495102957f768dc8b**At_Symbol_Here**



I think moisture (or water content) is a bigger problem for n-BuLi not just the oxygen content as it catches spontaneous fire when came in contact with air or moisture (C4H9Li + H2O =E2=86' C4H10 + LiOH) and releases highly flammable gas, butane. Butane further react in presence of oxygen to form carbon dioxide and water.


As per the MSDS sheet, LEL for n-BuLi is not available. I also tried to find but no luck.


Again that does not answer your initial question.




From: Yanchisin, Mark
Sent: Friday, September 25, 2015 12:23 PM
To: Singh,Shailendra
Subject: FW: [DCHAS-L] Pyrophorics




From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of NEAL LANGERMAN
Sent: Friday, September 25, 2015 12:03 PM
Subject: Re: [DCHAS-L] Pyrophorics




Thank you for the initial response; you have confirmed what I noted- the data do not seem to be available.


Allow me to change the question-

Some facts:

The specification for oxygen in cylinder nitrogen is less than 200 ppmv and it goes down as the quality of the nitrogen goes up.  Semiconductor grade is < 3 ppmv.


If you were monitoring the oxygen concentration inside a glove box (containment) using nitrogen as the purge gas, what would be the oxygen concentration at which you would say (IN YOUR WRITTEN SOP) that work with a pyrophor can begin.


It would be really helpful to have this answer documented with data; ideally peer-reviewed, but hard anecdotal - not just opinion - would be ok.


And, I really do not care about t-BuLi, but used it as an example.  Again, I am trying to find support for  pyrophor use which is analogous to hydrogen, where the data clearly support <5% being not ignitable no matter the hydrogen concentration.


Thank you for continuing this discussion




From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**] On Behalf Of Melissa Charlton-Smith
Sent: Friday, September 25, 2015 6:45 AM
Subject: Re: [DCHAS-L] Pyrophorics


Neal, are you speaking the common 1.5% to 1.7% solution in pentane?    The LEL of pentane is 1.5% (10% LEL, 1,500 ppm) which doesn't really answer your question about t-BuLi itself.  Like you I have searched and the best I could fine was how to isolate t-BuLi solutions to pure crystalline form, but it was never exposed to varying % of oxygen, all was done under argon and/or nitrogen.




From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**] On Behalf Of NEAL LANGERMAN
Sent: Thursday, September 24, 2015 4:15 PM
Subject: [DCHAS-L] Pyrophorics


Does anyone have any citations for the low limiting oxygen concentration of pyrophoric compounds.  I am specifically looking for the oxygen percentage at which compounds such as t-BuLi become non-ignitable.  For example, that value is 5% for hydrogen.  I have found a reference for silane, but, as is typical for silane, there are a myriad of confounding issues.


I have searched both SciFinder and Science Direct and have not found helpful data.








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