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Thread: Deoxygenation

  1. #1
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    Default Deoxygenation

    I need to deoxygenate several liters of polar solvents such as methanol and EG. I need these to remain as oxygen free as is PRACTICAL in some heavy wall polyethylene containers (not vacuum strong). I plan to flush an oxygen free gas such as nitrogen at about 1PSI, 24/7 whether the laser is running or not. What would be a best gas choice? Would some kind of O2 scavenging material within the container be a better choice than the flush?

  2. #2
    mixedgas's Avatar
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    Usually we use a Parker Balston N2 generator for this... Just N2 will be fine, or Argon.. You don't need much once you flush the top..

    There are oxygen scavenging filters, but they run about 100$ a filter cartridge.

    Steve
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    One company i worked for used nitrogen as well at low flow rates, they made there own fiber optic receivers with there own photo diodes made at the site so we had cabinets for the open ic cans and unmounted "naked" diodes, the devices where hermetically sealed but before every thing was in nitrogen, so a given item would be in a plexiglass box and the items in that,
    Polk SDA SRS, Parasound HCA 3500, Luxman M117, Onkyo 504, 7.62X39, sometimes a ball on a string is the greatest of toys for us nonhuman types. oh and some lasers, lots of lasers

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    Many years ago I experimented with sonoluminescence here at work, and thus needed a large(ish) supply of de-oxygenated water. (Well, technically it needed to be completely gas-free, not just de-oxygenated, but I digress.) Since I didn't want to spend a truckload of money on an oxygen-scavenging ion-exchange cartridge for the lab DI water unit, I heated the water to boiling to drive nearly all the dissolved air out of it. Of course some air still dissolved back into solution as the water cooled, but I still ended up with fairly de-aerated water at the end. (Getting the damned sonoluminescence to work, on the other hand, was a grating, rage-inducing effort in self control! I learned that I don't ever want to do that experiment again...)

    Depending on how low your O2 spec is, I would think that raising the temperature of your solvents to near their boiling points while sparging with an inert gas (either argon or nitrogen) should strip most of the O2 out. Then, so long as you maintain a pad on top of the container while it cools, you shouldn't have any further issues. As the solvent cools it will tend to allow more of the inert gas into solution, but as long as your source gas is pure you shouldn't have any issues.

    Out of curiosity, why is dissolved O2 a concern?

    Adam

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    if you remove the air from water, don't you just get air?

    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

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    Because I have all the time in the world. I think I will take the purging technique and because the solvent is constantly flowing in a closed container, just wait for the O2 to disappear. There is also the possibility that under intense UV light O2 may be created by some chemical reactions and so continuous purging makes me feel a bit safer. UV illumination of O2 causes the formation of singlet O- that is very destructive to some laser dyes.

    The dissolved air in water is in equilibrium with atmospheric air. Replacing the air disrupts the equilibrium and you need to keep the atmosphere away from the water.

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