Sciencemadness Discussion Board

Scrubbing CO2 from welding argon

Mercedesbenzene - 17-7-2012 at 08:45

I want to synthesize 9,10-diphenylanthracene. It uses phenyllithium and must be conducted under an inert atmosphere. I don’t have nitrogen or pure argon but I have a tank of welding argon that is 15% CO2 according to the MSDS. I want to try scrubbing out the CO2 with several sodium hydroxide washes and then drying it over sodium hydroxide. I was wondering if anyone has any experience with this or has tried it before?

[Edited on 17-7-2012 by Mercedesbenzene]

DoctorOfPhilosophy - 17-7-2012 at 10:06

I don't know about other places, but at my local welding store they'll exchange Ar/CO2 for 99% Ar. Of course if you really need very pure Ar it's a moot point. Scrubbing is going to be messy and contaminate your mix with water vapor, have you considered a cold trap?

Pyro - 17-7-2012 at 10:19

is CO2 not inert enough for you?
it doesn't react with much

mr.crow - 17-7-2012 at 10:30

Quote: Originally posted by Pyro  
is CO2 not inert enough for you?
it doesn't react with much


Phenyllithium will

Also CO2 will react with NaOH to make Na2CO3 for example (in solution it forms carbonic acid)

Pyro - 17-7-2012 at 10:50

oh,
I suggest trading in the bottle for pure argon, over here they have both pure and Ar/CO2 in many different sizes.
do you know of a welding shop in your area?

Mercedesbenzene - 18-7-2012 at 10:42

For the sake of science I am going to try it on a very small scale. If it does not work then I will trade in my tank for a tank of 99% argon.

Gibberator - 23-7-2012 at 22:57

Run it through an aqueous solution of CaNO3 or some other Alkaline Earth nitrate? Wouldn't it precipitate out as the Alkaline Earth carbonate?