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mericad193724
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Ammonia Gas Generator
I would like to make some concentrated ammonia solutions. The Ammonia I get from the supermarket for cleaning is VERY dilute. I read that an ammonium
salt and sodium hydroxide heated in an aqueous solution will produce ammonia gas.
Would Ammonium Nitrate and Sodium Hydroxide be a dangerous?...Ammonium nitrate is a strong oxidizer which can explode when heated to dryness so I just
want to make sure it is safe to heat a concentrated Ammonium nitrate solution with hydroxide. (Drain opener and Ice pack).
Thanks,
Mericad
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Jdurg
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| Quote: | Originally posted by mericad193724
I would like to make some concentrated ammonia solutions. The Ammonia I get from the supermarket for cleaning is VERY dilute. I read that an ammonium
salt and sodium hydroxide heated in an aqueous solution will produce ammonia gas.
Would Ammonium Nitrate and Sodium Hydroxide be a dangerous?...Ammonium nitrate is a strong oxidizer which can explode when heated to dryness so I just
want to make sure it is safe to heat a concentrated Ammonium nitrate solution with hydroxide. (Drain opener and Ice pack).
Thanks,
Mericad |
No, Ammonium Nitrate will not explode if heated to dryness. It will decompose into nitrogen oxides and other nasty stubstances as the temperature
rises, but you're not going to set off a massive explosion by heating up a pile of NH4NO3. I honestly have no idea how that myth got propagated and
why it still exists to this day. Ammonium Nitrate requires a fairly substantial shock to get it decomposing explosively. Hence why blasting caps are
used.
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UnintentionalChaos
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That would work in theory, though I have never done it before. Afterward, you are left with NaNO3 which you could mix with KCl road salt (have to look
for the right salt) and recrystallize for KNO3. It should be a sin to waste nitrates. 
Edit: issues with CuSO4 theory. Hydroxide becomes an issue.
[Edited on 1-17-07 by UnintentionalChaos]
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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YT2095
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KOH and AN mixed in soln is exactly how I make mine also, it requires gentle heat and a Very cold capture vessel, but other than that, it`s about as
simple as it gets.
the KNO3 is great for feeding Chili plants with too 
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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roamingnome
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i hope to use ammonium sulphate, this should work as well, heating with CaO right?
nitrate may be exspensive, ammonium sulphate is well, certain dirt is actaully more pricey....
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garage chemist
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I make my ammonia gas by boiling ammonia solution under reflux, the gas comes out at the top of the condenser.
The temperature of the boiling solution is measured and slowly approaches 100°C as the NH3 is driven out. As it reaches 100°C, all ammonia has been
expelled.
I think this is the most economic method, but for dilute NH3 solutions you will need a large boiling flask so that enough NH3 can be evolved before
having to change the solution.
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Sauron
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FYI ammonium nitrate plus NaOH as solid mixture is the simplest and oldest gunsmith's blueing salts mix for the "blueing" of steel parts of firearms.
This is done at a high temperature in an extremely concentrated solution and my recollection is that when this is mixed with offgases a lot of NH3.
Not a pleasant process to conduct, it is done in black iron tanks heated with long burner tubes fed from LPG tanks. Gunsmiths often face serious burns
from hot concentarted caustics. There are various proprietary modifications to the simple AN/lye mix for blueing some alloys, even stainless steel.
Brownell's the the suplier in USA.
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joeflsts
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| Quote: | Originally posted by mericad193724
I would like to make some concentrated ammonia solutions. The Ammonia I get from the supermarket for cleaning is VERY dilute. I read that an ammonium
salt and sodium hydroxide heated in an aqueous solution will produce ammonia gas.
Would Ammonium Nitrate and Sodium Hydroxide be a dangerous?...Ammonium nitrate is a strong oxidizer which can explode when heated to dryness so I just
want to make sure it is safe to heat a concentrated Ammonium nitrate solution with hydroxide. (Drain opener and Ice pack).
Thanks,
Mericad |
I've had good luck with gently heating Ammonium Chloride with Calcium Hydroxide in water.
Joe
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YT2095
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NaOH (as he mentioned) does indeed work 
the driver for the calcium reaction is very weak, if it was ammonium Sulphate or Carbonate it should work like crazy
[Edited on 17-1-2007 by YT2095]
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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woelen
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I have made NH3 gas (humid) by mixing solid (NH4)2SO4 with solid NaOH, crushing the mix somewhat, and then adding a few drops of water, such that you
get a white wet mess. Gentle heating produces almost pure NH3-gas which is quite humid though. This gas can be absorbed in a receiver flask, filled
with distilled water.
I also have done this with NH4Cl instead of (NH4)2SO4. It works equally well.
Another method I have is heating (NH4)2CrO4 very gently. It leaves behind (NH4)2Cr2O7 and produces lots of ammonia and water vapor.
For someone, less rich in chemicals, probably the ammonium sulfate or ammonium nitrate route is best.
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guy
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Wouldnt using a carbonate be better? NaOH is too precious nowadays.
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DeAdFX
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One could also use Urea and the enzyme Urease. The greatest difficulty in this is isolating the enzyme.
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roamingnome
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Department of Dental Pathology and Therapeutics, University of Illinois, College of Dentistry, Chicago, Ill.
Bacteria capable of producing urease were found in 92.8% of 405 salivary samples from 82 patients. In 65.4% of the samples, appreciable quantities of
urease were produced.
awsome ill just spit on my piss
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YT2095
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| Quote: | Originally posted by guy
Wouldnt using a carbonate be better? NaOH is too precious nowadays. |
you`de make ammonium carbonate that way though, and although it does break down with heat it`s extra work.
unless you had Ammonium carbonate to start with, then almost any hydroxide will convert it, Calcium hydroxide would be great to use then.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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garage chemist
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Ammonium carbonate decomposes in solution by itself, no base has to be added. But what evolves is a mix of CO2 and ammonia.
Ammonium chloride and nitrate can be converted to ammonia using calcium hydroxide in aqueous suspension, the only difference being that you have to
heat stronger than with NaOH.
So the NaOH can be replaced by the cheaper Ca(OH)2.
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franklyn
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| Quote: | Originally posted by mericad193724
I would like to make some concentrated ammonia solutions. The Ammonia I get
from the supermarket for cleaning is VERY dilute. I read that an ammonium salt
and sodium hydroxide heated in an aqueous solution will produce ammonia gas.
|
I don't understand your meaning of dilute unless you only have access to
household cleaners which only contain some ammonia as an ingredient.
Commercially available clear ammonium hydroxide available in supermarkets is
a solution close to saturated. To expell the gas you only need to mix in quick lime
CaO if Na2O is a problem for you. This is quite vigorous and should be done in the
open or you may have to evacuate from indoors if there is a leak so start small.
Here is a chemists proceedure in detail please observe the warnings
ammonia inhalation can certainly kill you.
http://designer-drug.com/pte/12.162.180.114/dcd/chemistry/el...
.
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Jdurg
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Ummmm..... the ammonia solutions you get in a grocery store are typically around 3% which is so incredibly far from saturated. You need a great deal
of that solution in order to make some concentrated ammonia solutions.
\"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists of the unmistakable scent of broccoli, and usually
requires wiping afterwards.\"
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garage chemist
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In France you could buy 20% ammonia for less than 1€ per Liter. I bought four liters for filling my gas bottle (using a fridge compressor). 500ml
liquid anhydrous ammonia for less than 4€, that was a really good idea. The gas bottle is still about half full.
Sadly the 20% has now been replaced with 12%, which costs the same.
In germany the OTC ammonia solution is 9%, and it costs about 4€ per liter. This is not worth the money at all. Better buy the 25% stuff over the
internet.
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guy
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| Quote: | Originally posted by garage chemist
Ammonium carbonate decomposes in solution by itself, no base has to be added. But what evolves is a mix of CO2 and ammonia.
Ammonium chloride and nitrate can be converted to ammonia using calcium hydroxide in aqueous suspension, the only difference being that you have to
heat stronger than with NaOH.
So the NaOH can be replaced by the cheaper Ca(OH)2. |
First you would form NH3 and a bicarbonate ion. Further reation of the bicarbonate with ammonium will make CO2 and NH3.
So if you dont want CO2, then use more carbonate.
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YT2095
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another good tip when making ammonia soln is to use an upside down funnel just a little way under the surface of the receiver vessels liquid.
NH3 is Very soluble in water and you risk Suck-back into your reaction vessel.
using a funnel gives you a greater surface area of gas liquid interface and if suck-back starts if can only progress a little way up inside the funnel
before the seal breaks and the releases the liquid again.
it`s really worth that little bit extra time and effort to do
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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unionised
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"No, Ammonium Nitrate will not explode if heated to dryness. It will decompose into nitrogen oxides and other nasty stubstances as the temperature
rises, but you're not going to set off a massive explosion by heating up a pile of NH4NO3. I honestly have no idea how that myth got propagated and
why it still exists to this day. Ammonium Nitrate requires a fairly substantial shock to get it decomposing explosively. Hence why blasting caps are
used. "
My best guess as to why this idea still exists is that it seems to be true.
For example see this
http://www.unep.fr/pc/apell/disasters/toulouse/home.html
and for another 16 examples see this
http://en.wikipedia.org/wiki/Ammonium_nitrate
What I don't understand is why people insist that it doesnt happen.
OTOH, in the circumstances we are talking about it isn't a problem The stuff will give off the ammonia as soon as it gets warm and then there's no
fuel for the reaction.
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Aqua_Fortis_100%
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| Quote: | originally posted by garage chemist:
Ammonium chloride and nitrate can be converted to ammonia using calcium hydroxide in aqueous suspension, the only difference being that you have to
heat stronger than with NaOH.
So the NaOH can be replaced by the cheaper Ca(OH)2.
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i have NO NH4NO3 or NH4Cl, so my "usual" generator of NH3 gas is (NH4)2SO4/NaOH mix... i tried make NH3 via ammonium sulphate salt and Ca(OH)2
(really MUCH cheaper than NaOH).. but only a weak smell of NH3 was observed and the reaction stops quickly... i think which should be the
insoluble CaSO4 formed.. but i haven't tried heat this.. will work if heating this ???
thanks
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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Organikum
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| Quote: | Originally posted by DeAdFX
One could also use Urea and the enzyme Urease. The greatest difficulty in this is isolating the enzyme. |
One could also just heat the urea. IIRC up to about 180°C only NH3 is produced.
/ORG
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YT2095
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Avoid Alcohol!
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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Jdurg
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| Quote: | Originally posted by unionised
"No, Ammonium Nitrate will not explode if heated to dryness. It will decompose into nitrogen oxides and other nasty stubstances as the temperature
rises, but you're not going to set off a massive explosion by heating up a pile of NH4NO3. I honestly have no idea how that myth got propagated and
why it still exists to this day. Ammonium Nitrate requires a fairly substantial shock to get it decomposing explosively. Hence why blasting caps are
used. "
My best guess as to why this idea still exists is that it seems to be true.
For example see this
http://www.unep.fr/pc/apell/disasters/toulouse/home.html
and for another 16 examples see this
http://en.wikipedia.org/wiki/Ammonium_nitrate
What I don't understand is why people insist that it doesnt happen.
OTOH, in the circumstances we are talking about it isn't a problem The stuff will give off the ammonia as soon as it gets warm and then there's no
fuel for the reaction. |
Well did you notice some common things apparent in all of those descriptions? Either some type of priming explosive hit the mass of ammonium nitrate
which would put the required detonation wave through the mass, or the incident involved HUGE quantities of the compound which will instantly alter
it's properties. The greater the mass you have, the higher the likelihood of localized "super-dense" areas. E.G., if you have a massive quantity of
feathers piled on top of each other, the feathers in the very middle will be locally MUCH more dense than those on the edge.
When you deal with explosives, this very close proximity caused by the heavy stacking of ammonium nitrate crystals causes the required detonation wave
going through the mass to be less and less and less. (Since when the resulting detonation velocity from the tiny bit of NH4NO3 goes "boom", it will
be able to interact with a lot more NH4NO3 and set off a lot of little tiny "booms". A lot of little tiny "booms" is just as destructive as one big
"boom").
In the quantities of NH4NO3 that people have lying around their labs, I just don't see the ammonium nitrate detonating unless you really work hard at
getting it to do so.
\"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists of the unmistakable scent of broccoli, and usually
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