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Chemical to absorb oxygen and nitrogen

  1. Jul 29, 2012 #1
    Is there a chemical that can absorb oxygen and nitrogen and in solid form.
    I need to make a vacuum in a pvc pipe or close to a vacuum.
    I was wondering if there were some chemicals that I could insert into the pipe and then close the end and tip it over and mix the chemicals together that would absorb the oxygen and nitrogen in the pipe and make it close to vacuum.
     
  2. jcsd
  3. Jul 30, 2012 #2
    One problem with that idea is that the reduction in pressure would oppose the absorption from taking place. Think about what happens to a human in a vacuum. All the gases in the lungs and blood stream get violently pulled out of the body, If you found a solid substance that absorbs these gases effectively, it wouldn't be able to retain the gases in low pressure environments. You could use a substance that reacts with the oxygen and form a highly stable solid complex with it but a similar problem exists, the lower the pressure, the lower the extent of reaction that can take place.

    Why not just depressurise the pipe the conventional way, using a vacuum pump?
     
  4. Jul 30, 2012 #3
    ok i see your point. Ill see if I can get a pump
     
  5. Jul 31, 2012 #4
  6. Mar 14, 2013 #5
    With respect to the solid compound, a burning strip of Mg. Reaction with nitrogen, per Wikipedia (http://en.wikipedia.org/wiki/Magnesium_nitride )

    "Magnesium nitride can be produced by heating magnesium metal in a pure nitrogen atmosphere.

    3 Mg + N2 → Mg3N2

    In fact, when magnesium is burned in air, some magnesium nitride is formed in addition to the principal product, magnesium oxide."

    Note, per Wikipedia, some CO2 and water vapor can also be removed as well:

    2 Mg + CO2 --> 2 MgO + C

    Mg + H2O --> MgO + H2

    [EDIT] I would also add CaCl2 as any moisture could react with the Mg3N2 to form NH3. Reaction:

    Mg3N2 + 3 H2O --> 3 Mg(OH)2 (s) + 2 NH3 (g)

    Ammonia reacts with CaCl2 as follows forming adducts:

    CaCl2 + 4 NH3 --> CaCl2.xNH3 (where x=1, 2, 4 or 8)

    and the CaCl2 will also absorb any water vapor.

    I still suspect, however, there will be some N2 remaining even with excess Mg. Note also, burning Mg is very hot (3,100 C) and gives off strong uv radiation.
     
    Last edited: Mar 14, 2013
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