LD5050
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Can nitrous oxide be used as an inert gas?
Can I use nitrous oxide as an inert gas to store chemicals under? Or when distilling benzaldehyde? I know at elevated temperatures it can be used as
an oxidizer but at rooms temp it is relatively inert.
I have a bunch of nitrous oxide bottles that is why I would like to use this instead of going out and buying nitrogen.
[Edited on 4-23-2017 by LD5050]
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unionised
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Near room temperature it's pretty unreactive, but if there's some sort of accident it will make things a whole lot worse.
You can almost certainly detonate a mixture of benzaldehyde and N2O.
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AJKOER
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Careful, if you are wearing clothing prone to producing electrostatic shocks (or discharge, abbreviated as ESD) and are in touch with a N2O infused
fuel.
Here is a link to my prior research and experimenting with N2O https://www.sciencemadness.org/whisper/viewthread.php?tid=32... .
My recent readings suggest that N2O infused into an aqueous suspension of select metal oxides (TiO2, ZnO, MgO, FeOOH, ...) in solar light is a path to
hydroxyl radicals. My rough take on the chemistry:
ZnO + hv ---) e- + h+
e- + nH2O ---) e-(aq)
e-(aq) + N2O ---) N2 + .O-
.O- + H2O ---) .OH + OH-
Note, so called Fe(lll) (hydr) oxides occur in natural waters (see http://www.sciencedirect.com/science/article/pii/03044203950... ). As such, the action of light may induce some unexpected radical activity in
the presence of N2O tap water compositions.
[Edited on 23-4-2017 by AJKOER]
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LD5050
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A mixture of benzaldehyde and No2 could detonate, how so?
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alking
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I'm not sure he's saying it would autoignite, just that it's potentially explosive as benzaldehyde is quite flammable and N2O is a strong oxidizer.
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unionised
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FFS! learn the difference between N2O and NO2
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JJay
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In a word, no, you can't use nitrous oxide for that.
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clearly_not_atara
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Between N2O and CO2 I would consider the latter to be far more "inert", particularly w.r.t. benzaldehyde.
I've started to think the amateur chemistry community needs to get a lot better at generating N2 gas. All you really need is an aliphatic primary
amine without an adjacent EWG (so no amino acids) and a source of nitrosyl. Amines with an adjacent EWG will form "relatively stable" diazo compounds
with sodium nitrite but others will react to release nitrogen particularly in the presence of nucleophiles like chloride.
The reaction between ammonia and nitrite is second-order with respect to nitrite (first-order w.r.t. ammonia) unless HCl is present to generate NOCl,
and usually requires N2O3 to be present in sol'n. But we don't want to generate NOCl or other nitrogen oxides for that matter. So dripping nitrite
into ammonia is out of the question (too slow) and dripping ammonia into nitrite means there will be noxious gases effervescing from the nitrous acid
solution during the reaction.
But what about the reaction between ammonia and isopropyl nitrite? This should certainly be first order. Assuming isopropyl nitrite reacts with
ammonia as fast or faster than it reacts with water, dripping isopropyl nitrite into an ammonia solution seems like one way of making N2 that should
work rather well.
Or isopropyl nitrite turns out not to be reactive enough for this and I have run in circles.
[Edited on 24-4-2017 by clearly_not_atara]
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JJay
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Quote: Originally posted by clearly_not_atara  |
I've started to think the amateur chemistry community needs to get a lot better at generating N2 gas.
[Edited on 24-4-2017 by clearly_not_atara] |
I have thought the same thing... decomposition of azides is thought to produce extremely pure nitrogen, but that seems a little involved. Sulfamic
acid and sodium nitrite react to produce nitrogen, but I have been told that it isn't very pure.
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Elemental Phosphorus
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A lot of gases are relatively inert, N2 being the cheapest. But seriously, buy a little argon or something if you need it a lot, or if not, you could
probably use propane, as it is pretty much inert, except with strong oxidizers. Carbon dioxide should do the job as well, no problem. Out of all the
gases that are relatively inert, you had to choose N2O, while there are plenty of gases that should prevent the auto-oxidation to benzoic acid, N2O is
likely not one.
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Melgar
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Bubbling propane through nitric acid, and then running that through sodium hydroxide to get rid of the nitric acid and water, will remove the
mercaptans from commercial propane. Granted, there won't be much of it, but there's been enough to produce a sulfide coating on metal samples I've
stored under propane before. Another option is to just put oxygen, water, and CO2 scavengers in a bucket, then use that bucket as your inert gas
source, filling it with air when you're done using it.
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XeonTheMGPony
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Molecular sieve N2 concentrators are even better, old fridge pump, some valves and don!
Will post a link to a home made diy Nitrogen concentrator when I get home from work (Which may be sooner then later if the weather keeps going the way
it is!)
http://www.instructables.com/id/Nitrogen-gas-generator/
http://homemadeliquidnitrogen.com/ Read through this guys build blog will be very educational in a few ways!
then using a O2 scavenger followed by a final Molecular sieve finish the gas stream
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AJKOER
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Make a H2 generator and use it to fuel a hydrogen flame.
Inert the flame into a container of air to form an atmosphere of N2 and water vapor.
Use a packet of CaCl2 to create dry nitrogen.
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Melgar
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And $500 and a week later, problem solved! Seriously though, this machine is way more useful as an oxygen concentrator, and it's how they concentrate
oxygen for old people who can't breathe well. It's referred to as a "pressure swing adsorption oxygen concentrator", and separates air into oxygen
and nitrogen (about 99% of dry air). My friend and I had the plans drawn up for a 20 L/min unit with regards to air, which would be about 4 L/min of
oxygen. The air should really be dried before it enters the apparatus anyway, meaning it'll be dry when it comes out. The oxygen supply can be
connected to an ozone generator to generate useful levels of ozone, or a contact-process H2SO4 generator, which will make it easier to run on a small
scale. I'm sure there are plenty of other reactions that would benefit from a source of pure oxygen.
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MrHomeScientist
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| Quote: Originally posted by AJKOER | Make a H2 generator and use it to fuel a hydrogen flame.
Inert the flame into a container of air to form an atmosphere of N2 and water vapor.
Use a packet of CaCl2 to create dry nitrogen. |
You're forgetting all the other components of air. CO<sub>2</sub> being the main concern from an inertness standpoint.
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AJKOER
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To some extent I expect the CaCl2 to collect H2O which, on cooling and shaking, may have soaked up the likes of CO2, NO2, SO2,...So do not introduce
the CaCl2 until after some cooling/shaking has occurred.
The real left over is hydrogen that was inserted as the H2 flame dies out and was not removed quickly.
However, H2 is so light I would expect a top layer formed over the nitrogen, so not hopefully a problem, but I would store cold and away from light.
---------------------------------------------------------------
[Edited on 25-4-2017 by AJKOER]
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MrHomeScientist
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All gases are infinitely miscible, sometimes surprisingly so. I wouldn't count on a distinct layering in a gas mixture.
Once I tried the "float a tinfoil boat on SF<sub>6</sub>" experiment by filling a fish tank with the gas and floating things on it.
Despite being 6x denser than air, it diffuses out of the tank surprisingly quickly. I left it alone for 20 minutes with a piece of cardboard as a
loose cover (to protect from air currents), but when I got back maybe 2/3 of it had escaped anyway.
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