Gargamel
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Storing concentrated ammonia water
When I concentrate ammonia, I often cannot use up everything.
Now, let's imagine I have have reached some 25%.
This should give about 50.000 pascal or some 0,5bar at room temperature.
Two questions:
If I put this into a good quality glassbottle with teflon seal
-will this break the bottle? Would you feel save with that?
-will containing the pressure create an equilibrium, preventing further loss of NH3?
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Tsjerk
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I buy 25% ammonia in plastic bottles and use those to store it for years now. Temperatures go up to 35 degrees which doesn't seem to be a problem.
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SWIM
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The vapor pressure is .5 bar, but when you close a bottle of strong ammonia the gasses in there at atmospheric pressure already include a considerable
partial pressure of ammonia gas.
So the pressure isn't going to increase by .5 bar but just the difference between .5 bar and the partial pressure of ammonia in there when the lid was
closed.
Edit: I suppose venting the bottle by loosening the cap if it develops much internal pressure would reduce the air in the bottle and therefore the
overall pressure when the closed bottle gets back to equilibrium, but I too have just stored strong ammonia in plastic bottles with no special
precautions and had no trouble.
I don't recall the bottles developing much pressure, but that was a long time ago.
[Edited on 19-11-2021 by SWIM]
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Sulaiman
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I believe that bottled carbonated drinks typically have 2.5 to 5 bar internal pressure,
Champagne up to 6 bar.
so 0.5 bar is trivial.
BUT
hdpe bottled strong ammonia solutions tend to leak gas a little over time,
as evidenced by a fine dusting of ammonium chloride in my plastic tub used to store acids, bases and some solvents.
(conc. HCl solution is also difficult to completely seal in a hdpe bottle)
That was when I stored stuff in my shed in uk
here in Malaysia (3oN) I use 375ml brown glass pop (soda) bottles to re-bottle stuff that arrives in hdpe bottles.
So far (2 years) no problems with conc. hydrochloric, sulphuric, nitric acids, 50% H2O2, acetone etc.
[Edited on 19-11-2021 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
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woelen
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No problem to store ammonia up to even 30% in ordinary glass or plastic bottles. It is sold in such bottles and can be kept in them for years. I have
a 5 liter jerrycan with 30% ammonia and I store that, also in summer, without any issue.
[Edited on 19-11-21 by woelen]
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j_sum1
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I store mine in 500mL glass bottles in my lab fridge. I hate being greeted by a waft of ammonia when I open the bottle.
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Molybdenumb
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When I used to work in a purification plant, we stored our 35% 1 L samples in PTFE or LDPE/HDPE bottles with no issues. We retained samples in a
non-climate controlled warehouse in a desert so even heated they were good to go.
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Gargamel
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Thank you guys for your answers.
Please forget about plastic bottles, I had one myself and it was like a balloon.
Those would never explode of course. But I have never seen any commercial vendor to use glass - in contrast to acids. That's why I had my doubts...
But by giving the fumes more room on one hand and on the other letting small amounts of gas escape all the time, they sure do not help in longer
storage.
(Long means some months or so)
Somehow I cant concentrate this week, winter depression starts to kick in...
Can you confirm my understanding of physics, that the higher pressure inside the glassbottle will help to keep the NH3 in solution, thus prolonging
the useful shelf life?
Or in other words, keeping the strength of the solution constant indefinitely (taking for granted the seal is a perfect one)?
[Edited on 19-11-2021 by Gargamel]
[Edited on 19-11-2021 by Gargamel]
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SWIM
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The partial pressure of ammonia above the fluid is what matters.
When it reaches the vapor pressure of the ammonia it will be in equilibrium.
[Edited on 19-11-2021 by SWIM]
When it reaches equilibrium the total internal pressure will be the vapor pressure of the ammonia plus the sum of the partial pressures of all gasses
and vapors inside the bottle.
It will reach equilibrium under partial vacuum if no other gasses are in there but ammonia and water vapor.
[Edited on 19-11-2021 by SWIM]
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DraconicAcid
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Quote: Originally posted by Gargamel  |
Please forget about plastic bottles, I had one myself and it was like a balloon.
Those would never explode of course. |
I'm a winemaker, and I have seen fermenting liquids blow a plastic pop bottle to smithereens. They wouldn't explode with ammonia, but never say
never.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Tsjerk
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Pressure keeps gasses in solution like pressure suppresses boiling points.
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SWIM
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So the vapor pressure of a substance varies with the pressure of whatever gasses are above it?
You sure about that?
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RustyShackleford
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only if the pressurised gas is the same gas as youre trying to keep from coming out of solution.
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Tsjerk
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When you read a vapor pressure to be example given 0.5 bar, that will be the concentration of the gas of the compound referring to. but that does not
mean there will be a pressure of 1.5 bar when the ambient pressure is 1, it means 50% of that 1 will be the compound.
As long as you don't replace the gas above the solution you will have a pressure of 1 bar as RustyShackleford says. When you do replace the gas you
will get a pressure somewhere between ambient and the vapor pressure plus ambient, as the pressure is generated by the compound, which keeps itself in
solution.
[Edited on 20-11-2021 by Tsjerk]
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SWIM
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I think I see what you mean.
And I get what Rusty said
Edit: What RustyShackleford said.
[Edited on 20-11-2021 by SWIM]
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karlos³
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Yeah I bought a canister 5l of 25% of the stuff, and(no don't) due to ease I store it(its down to like a tenth) in the bathroom upstairs.
I gets a bit bubbly looking in winter(because of the heating, d'uh!) or hot summer heat but thats cool, no issues.
It was less of a worry when it was more full though(less room to expand obviously).
But I bought that in 2017 and store it not in the cold for quite some time now.
I can tape a wet stripe of pH paper around the tight fitting opening for fun though.
I will look if its HPDE or PP.
Tight af though(meaning, as foretold).
[Edited on 20-11-2021 by karlos³]
verrückt und wissenschaftlich
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Gargamel
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Thanks again 
| Quote: |
Yeah I bought a canister 5l of 25% of the stuff, and(no don't) due to ease I store it(its down to like a tenth) in the bathroom upstairs. I gets a bit
bubbly looking in winter(because of the heating, d'uh!) or hot summer heat but thats cool, no issues. It was less of a worry when it was more full
though(less room to expand obviously). But I bought that in 2017 and store it not in the cold for quite some time now. |
In many cases that does not matter, but it would be interesting to know how much of the 25% are still left.
[Edited on 21-11-2021 by Gargamel]
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Sulaiman
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WARNING... DANGER
For some domestic cleaning I decided to use some of my 47% hydrogen peroxide,
stored in a couple of the 375ml brown glass bottles in my post above.
Just a little domestic cleaning - no need for PPE.
On unscrewing the bottle top... POP!
(louder than a champagne cork)
My eyes shut tight and I thought that the glass bottle had exploded in my hand.
When I opened my eyes I saw that the glass bottle was intact,
about 1/3rd of the peroxide was on the table and the metal screw top was bent (possibly me squashing it due to the shock)
Amazingly nothing in my eyes, on my face, arms or body, a little liquid on my fingers was quickly rinsed off with no bleaching of my skin.
Luckily the table is glass so easily cleaned up with no damage.
I WAS EXTREMELY LUCKY.
I carefully opened my other glass bottle of peroxide from the same source hdpe bottle as the exploded bottle,
just a slight buildup of pressure - the normal sort of pressure that I was expecting from the exploded bottle.
I guess that the exploded bottle had in it some kind of catalyst for the decomposition of peroxide.
Anyway, scary and obviously very hazardous
So
I can no longer recommend tightly sealed glass bottles for hydrogen peroxide,
ammonia solution may have a similar hazard?
I'm not sure what I'll do next.....tbd
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Tsjerk
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You are missing the intrinsic difference between hydrogen peroxide and ammonia. Hydrogen peroxide is not a gas when pure to start with, but also
hydrogen peroxide decomposes into gasses that don't dissolve.
Ammonia is a gas and will stay a gas which will stay in solution. It doesn't decompose.
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Sulaiman
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True, sloppy of me. Thanks.
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Tsjerk
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Good to hear your accident was without too much harm! Forgot to say that.
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Triflic Acid
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Ammonia is fine for HDPE bottles, even in the heat. My delivery man was a bit of an idiot and left the package with 500mL of conc. Ammonia on a bush
in the sun, and I didn't notice for a few hours. The temperature outside that day was around 100. F, not C of course. But anyway, when I found it had
swollen considerably, but cooling in ice and after venting the pressure in the hood, the bottle was fine and is still my go-to source for conc.
ammonia these days.
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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AJKOER
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For the record, if anyone wants to store a high concentration of ammonia, do not discount 'storing' it chemically!
For example, as NH4Cl or (NH4)2SO4 and when you want the NH3:
NaOH (s) + NH4Cl (s) -> NH3 (g) + H2O (l) + NaCl
Ca(OH)2 + (NH4)2SO4 -> 2 NH3 (g) + 2 H2O (l) + CaSO4 (s)
Note: Adding Epsom Salts to dilute cheap ammonia water is a source of ammonium sulfate and a good amount of a white suspension of Mg(OH)2.
This also has the advantage of removing the danger (and any anxiety) that arises from storing hazardous chemicals properly along with not having to
explain why one particularly needs them.
[Edited on 1-12-2021 by AJKOER]
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theAngryLittleBunny
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| Quote: Originally posted by Gargamel | When I concentrate ammonia, I often cannot use up everything.
Now, let's imagine I have have reached some 25%.
This should give about 50.000 pascal or some 0,5bar at room temperature.
Two questions:
If I put this into a good quality glassbottle with teflon seal
-will this break the bottle? Would you feel save with that?
-will containing the pressure create an equilibrium, preventing further loss of NH3?
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Unless you keep the bottle in a hot environment there is no risk of the bottle bursting (and probably even then it couldn't burst), there might just
be a bit of pressure released when opining the bottle. I have a bottle with diethyl ether and dichloromethane which I just keep at room temperature.
It would sometimes just release a bit of pressure when opening it, usually when I poured some out the last time and thereby poured out all the vapour
in the headspace. Even in summer at 30°C it was never a problem.
I also had 22% ammonia in a HDPE bottle which worked fine and it never built up any noticeable pressure. Just don't ever store it in a PET bottle, it
will dissolve it over a few weeks and burst.
You can even store liquids in bottles with a boiling point below the temperature of the environment you store it, as long as the boiling point isn't
too low. For instance butane boils at 0°C, but a simple PET bottle has no problem holding it at room temperature (I wouldn't store it in there for a
long time though). The pressure it creates it pretty much the same as the pressure in an unopened coke bottle. One video from TKOR showed that PET
bottles can even hold propane at room temperature (I wouldn't try that though).
[Edited on 6-12-2021 by theAngryLittleBunny]
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