The title says it - I need a preferably aqueous non-volatile solution of material x that efficiently scavenges oxygen from air, leaving largely just
nitrogen (CO2 etc, doesn't matter happens with it).
What I tried so far is dithiothreitol, DTT, but it isn't efficient enough.
I was thinking of perhaps dithionite, but I'm not sure how efficient it is to capture oxygen from air.
It needs to be something fairly aggressive and efficient, availability shouldn't problematic as almost anything can be ordered.
Any advice?Nicodem - 27-10-2008 at 06:57
Usually a basic aqueous solution of pyrogallol (1,2,3-trihydroxybenzene) is used for such purpose (like in the gas analysis). It is quite efficient. I
think a ~25% aqueous solution basified with KOH is generally used.unionised - 27-10-2008 at 10:03
Pyrogallol is certainly the traditional way to do this.
For those who like inorganic chemistry (or for circumstances where the organics from alkaline pyrogallol can't be tolereated) Chromium (II) sulphate
is sometimes used.
(Chrome (IIII) sulphate+ H2SO4(aq) +Zn - leave it till it goes blue.)gsd - 27-10-2008 at 10:22
Is it necessary that it has to be a "Chemical"?
The PSA - Pressure Swing Adsorption - Technology uses Zeolites / molecular sieves to selectively separate Nitrogen from air, leaving it rich in
Oxygen. Check here:
[Edited on 27-10-2008 by gsd]woelen - 27-10-2008 at 10:26
Pyrogallol is quite expensive.
If shaking is allowed, then hydroquinone definitely is the first choice, but if mere bubbling of the gas-mix through the solution must remove all
oxygen, then try catechol in a tall column, instead of pyrogallol. Catechol is less expensive than pyrogallol, but more expensive than hydroquinone.kclo4 - 27-10-2008 at 15:46
Hmm I have read that activated carbon can remove oxygen from the air. I doubt this does it effectively, but I figure it can only help to mention it.
What is it you are doing with deoxygenated air?
Perhaps some options could be considered if we knew what you were doing.
[Edited on 27-10-2008 by kclo4]S.C. Wack - 27-10-2008 at 16:30
This (Fieser's solution) is naturally in both of my Fieser scans.chemoleo - 27-10-2008 at 16:51
Thanks very much.
Yes it would have to be a chemical solution, as it has to be pipetted into tiny chambers 0.2 cm^3 in volume, and the O2 should hopefully be captured
within <10 minutes once the chambers are sealed.
Nonetheless the pipetting means it's exposed to air during handling... so I wonder just how reactive basic pyrogallol (or sodium
anthraquinone-sulfonate + sodium hyposulfite) is.
I guess this can be tested - I imagine the assay using pyrogallol is spectrophotometric - what are the wavelengths? I checked my books but couldn't
find any specifics. If anyone has some info ready at hand, please post away, that would be much appreciated!
One caveat seems with this is that lots of KOH is used (hygroscopic) - and this is what the solution really should NOT be. What I found are conditions
such as 1:4 pyrogallol (25%): KOH (60%). Wonder if the reaction works in the absence (or just a little bit) of KOH. I think this will be ordered
soon.
PS S.C. Wack do you have access to the full paper?
[Edited on 28-10-2008 by chemoleo]chemoleo - 27-10-2008 at 17:04
Attachment: fiesero2.pdf (571kB) This file has been downloaded 484 times
Panache - 27-10-2008 at 20:26
There are innumerable O2 scavenging polymer film laminates now, with the scavengers laminated between the more inert polyolefin's, nylon or polyesters
films, or even bonded directly to the backbone and then laminated.
The positive would be that they are chemically inert essentially, if you use a film with an polyolefin outer layer such as polyethylene or propylene,
and you could line a small area nicely, the downside is i don't think they're going to work super fast like you mentioned depending upon your film
choice the O2 permeation to the scavenging layer could be hours to days
