[Bel-p]

Can someone tell me what the equation would be for getting Nitrogen N2 from air?  I've tried to look it up but can't find anything.

Then I wondered what the formula for air is, but there isn't such a thing.  I found this useful discussion about air:

Air has no chemical formula because it is made up of a whole bunch of stuff. It's a mixture. It would be like asking: what's the chemical formula of orange juice? Mixtures like orange juice or air don't have formulas. Orange juice is made up of water, sugar, citric acid, and small amounts of other stuff. Water, sugar and citric acid have chemical formulas, but the juice itself does not.

Similarly, air is like juice, but it's a mixture of gasses. It is made of mostly nitrogen and oxygen with a bunch of other stuff in small amounts. Here's the breakdown with their chemical formulas. By volume, air is about:
78.084% Nitrogen (N2)
20.947% Oxygen (O2)
0.934% Argon (Ar)
0.033% Carbon Dioxide (CO2)

With trace amounts of:
Neon (Ne)
Helium (He)
Krypton (Kr)
Sulfur dioxide (SO2)
Methane (CH4)
Hydrogen (H2)
Nitrous Oxide (N2O)
Xenon (Xe)
Ozone (O3)
Nitrogen dioxide (NO2)
Iodine (I2)
Carbon monoxide (CO)
Ammonia (NH3)
Water (H2O)

I understand from GCSE (UK qualification for 16 yr olds) chemistry books that Nitrogen comes from burning hydrogen in air to remove the oxygen.  The water vapour produced cools & condenses and the remaining gas is Nitrogen. But is there a formula?

[AWK]

For approximate calculations we use O2+4N2 formula.

Nitrogen can be separated from an air on an industrial scale by a liquefaction followed by a fractional distillation .

[constant thinker]

Air is just a conglomerate of molecules that are in a gaseous state and some solid particles (dust, smog, etc.) so there is formula for air. The closest thing is what AWK posted. He's right about what they do industrial. The compress regular air until it liquefies. Then through fractional distillation they get what they want out of it.

Nitrogen exists as N₂ in air. The two nitrogen atoms are triple bonded, and they form a strong bond that requires substantial energy (or something really reactive) to break. Under normal conditions nitrogen is inert in the air and just exists. There is no formula for extracting N₂ from the air. There is only an industrial process.

[Equi]

The orgininal process for liquefaction of gases was developed by Linde AG.
Some additional information
There's also a nice german wikipedia article about the Lindeverfahren

[billnotgatez]

Are the below quotes correct? I would have used the term cascading expansion cooling. Is this just a matter of semantics?


From
constant thinker

Then through fractional distillation they get what they want out of it.

From
AWK

followed by a fractional distillation

[AWK]

Are the below quotes correct? I would have used the term cascading expansion cooling. Is this just a matter of semantics?

You mean a method of liquefaction.
We are talking about the next step - separation of components from a liquid air.

[Bel-p]

OK, thanks everyone.

[Donaldson Tan]

Google for Linde Process!