RogueRose
International Hazard
Posts: 1585
Registered: 16-6-2014
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O2 & N2 generation/concentration + adding O3 generation
A member recommended that I look into a O2 concentrator for an experiement and I found that they work similar to air compressors but they use 2
cylinders partially filled with a molecular seive / zeolite which adsorb N2 and Ar when under >1.5 ATM of pressure, allowing the O2 to stay free in
the cylinder which is then vented as purish O2 (high 90% is easily possible). The same can be done with N2 but the adsorption is reversed where the
O2 is adsorbed into a carbon based substance but everything else is almost identical from what I could see (pressures may be slightly different, but
process seemed the same). The "exhaust" of the N2 generator can be anywhere from 40-85% O2 (usually higher concentrations as it is more efficient).
So depending upon the application, the exhaust of a N2 generator could be used for O2 source or putting the two in series, higher efficiencies could
be obtained if both gases are needed.
After reading how ozone (O3) is made with the "smoke eater" machines, it is a fairly simple process utilizing high voltage either by a coronal arc
(think lightening or a spark-gap), by UV or by electrolysis of H2O. Capacity is severely limited in the arc and UV process by O2 concentrations and
much greater efficiencies can be had if a purer source of O2 could be used. Calculating the cost between a larger O3 generator vs adding a source of
O2 would need to be done, but all units seem to be able to be built by someone with moderate technical and mechanical skills.
Every time I look at the applications and uses of O3 I am amazed and always learn something new and I would think being able to produce the three of
these gases very efficiently could be very useful in chemistry.
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Melgar
Anti-Spam Agent
Posts: 2004
Registered: 23-2-2010
Location: Connecticut
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I think it was probably me that recommended building an oxygen concentrator. And yes, one of the reasons I researched it was so that it could be used
to make ozone, which is especially good for cleaving double bonds between carbon atoms. However, conditions for this usually have to be extremely
well controlled, and temperatures usually have to be kept very low. Also, ozonides are generated, which are explosive. There is a variant of
ozonolysis that uses a small amount of water (~5%) dissolved in acetone or MEK at room temperature or lower, which decomposes the ozonides as they are
formed, however, this method works best for terminal alkenes.
As far as whether to use more air or concentrate the oxygen, definitely concentrating the oxygen is better. This is because otherwise you have huge
volumes of air moving through your solvent, which will cause it to evaporate very quickly.
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