Although argon is the third most common gas, it only makes up about 0. Commercially it is available as a by-product of industrial air separation. This is the only commercial source of Argon. Since it is such a small percentage of the atmosphere Argon is many times more expensive than Nitrogen. On the other hand, nitrogen is not a noble gas. Two nitrogen atoms make up the nitrogen molecule N 2 , so it has no free electrons like Argon and thus the same properties of a noble gas under nearly all uses.
Indeed, nitrogen, which makes up Therefore, the relatively commonplace nitrogen exhibits the same properties of argon but at much less cost.
Nitrogen is 88 times more abundant than argon. That means that the energy to produce a pound of nitrogen is 88 times less than the energy to produce a pound of argon. Argon production and distribution creates a large carbon footprint. For most users of nitrogen gas, on site air separation using pressure swing adsorption or hollow fiber membranes reduces the cost of nitrogen even more than relying on an air separation factory.
On site gas generation also minimizes CO 2 emissions by eliminating diesel truck deliveries of bottled or liquid nitrogen. One advantage of argon is its heavy weight. Argon has a density of 0. Not a good enough reason for me to give it a shot I will post the results.
Goatpoker Well-Known Member. Dumfast said:. Click to expand Goatpoker said:. Ar is a larger molecule and will actually leak out across the orings slower as well. Since you already have come up with an answer I'll threadcrap a little I used to tell guys this all the time and the reaction was mixed. I'd say if you really want to go full bling Neon is where it's at. Probably just me always looking for a way to work the word "Neon" into a conversation.
Muddi44 Well-Known Member. I think we should experiment with Xenon or Krypton as well. I wonder if you could get the Neon hot enough to glow in you shocks Monster Energy Green like a top racer. Ar is monoatomic while Nitrogen is diatomic, so the difference in leakage rate is probably immeasurable.
NoThrottle Active Member. I used to service avionics instruments, most were purged and sealed with nitrogen inside so they didn't fog up on the inside. Some of the fancy military stuff we filled with high purity helium instead because helium conducts heat away from hot components inside far better than nitrogen but the stuff will leak out of anything given enough time.
I see no reason why you could not use argon, if anything it's "more inert" than nitrogen. However, there are two other downsides to argon that come to mind. The first is price. I was actually tasked by our PI to be our argon monitor to make sure people weren't wasting argon. It was significantly more expensive than nitrogen, and the PI didn't care if you were just blowing nitrogen around.
The second one which people some times forget is that argon has a higher boiling point than nitrogen. If you're using argon in your manifold and cooling your trap with liquid nitrogen, you may condense argon in your trap. If then you close off your manifold without an outlet and the trap loses cooling, the manifold will be under intense pressure from the argon boil off. This presents a serious explosion hazard if you're not paying attention.
I don't think either is generally preferred over another, its project and situation dependent. For most organic reactions, it wont matter nitrogen is sufficiently non-reactive to be acceptable and the lower price makes it the go-to gas for most labs. However there is one consideration that makes argon attractive over nitrogen, and that is impurity levels. Although industrial grades for both gases are fairly pure, The specs for argon tend to have a lower impurity level of oxygen than for nitrogen , even though industrial grade nitrogen is typically purer than industrial grade argon.
Additionally nitrogen can more easily adsorb to surfaces which is the place where catalysts are active, thus it may be desired to reduce the amount of adsorbed material on a substrate like Raney nickel by using argon over nitrogen.
Consider though the cost of the reagents involved and the students time, it may not be that wasted of an investment to pay a little more for nitrogen to get more yield ever few reactions. Compare that to undergraduate labs, where there tends to be less serious research, the time scales of projects and are much shorter, the reactions are less sensitive and, are typically for pedagogical purposes, which brings me to my next point:.
Consider the implications of switching gases. Either 1 Everyone in the middle of research would be introducing a change in their experiment or 2 New Experiments would have to wait a year or two for current ones to complete or 3 a second gas system would have to be temporarily used to facilitate the long-term switch over.
None of these options are tenable unless the lab is up for remodeling, moving or new ownership and projects, thus the gas first used is the gas they continue to use.
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