Sciencemadness Discussion Board

Nitrous Oxide from Ammonium Nitrate

uzaymaymunu - 1-12-2012 at 14:59

Hi from turkey You have great forum, congratulations . I want to make N2O by decomposition(heating at about 200 celcius ) of NH4NO3. And purification with washing gas.

Is there anyone tried this? Some people say "ammonium nitrate can explode" But we know ammonium nitrate is very stable and it's seconder explosive, so imposible to explode by heating.

What do you think about this?

kristofvagyok - 1-12-2012 at 15:24

Yes I have made it long ago and I also know someone who had "problems" with it and really-really burned his hand.

The main problem with this reaction is the size. If you make it in a test tube then it is not a big deal. The problems come when you will try it with larger amounts, the main problem is when the bottom of the AN melts, the top is still solid and when it starts to decompose it will get overpressured in no time and could cause the flask to break. And the 200 C hot AN could be a really problematic.

uzaymaymunu - 1-12-2012 at 15:45

@kristofvagyok, i will heat ammonium nitrate in erlenmayer bulb. and forming gases (nh3+ nitrogen oxides + N2O + nh4no3 vapour ) will go gas washing solutions. Finally the pure N2O will fill in plastic balloon :)
All of these will be in atmospheric pressure. So it will never get overpresured.

Fleaker - 4-12-2012 at 17:27

Isn't it just easier to make N2O from sulfamic acid and nitric acid and be left with pure sulfuric acid? It's like $2.50/kg of N2O.

We use sulfamic to destroy nitric acid residues in aqua regia, and because N2O is a gas, it's favored. Heck of a lot faster than boiling it down!

woelen - 4-12-2012 at 23:32

You can also buy N2O for cream. It is sold OTC in metal ampoules, which easily can be ruptured. Each ampoule holds 8 grams of N2O and the gas can be released into a balloon. You only have to be very careful not to touch the ampoule immediately after release of the gas. The ampoule is cold, very cold and you certainly will have nasty frostbite when you touch it.

You could have a look for N2O ampoules in your area. I'm not sure about the situation in Turkey, but in many countries this stuff is easy to get your hands on. I can buy 50 of these ampoules for appr. EUR 10.

Adas - 5-12-2012 at 06:35

Quote: Originally posted by woelen  
You can also buy N2O for cream. It is sold OTC in metal ampoules, which easily can be ruptured. Each ampoule holds 8 grams of N2O and the gas can be released into a balloon. You only have to be very careful not to touch the ampoule immediately after release of the gas. The ampoule is cold, very cold and you certainly will have nasty frostbite when you touch it.

You could have a look for N2O ampoules in your area. I'm not sure about the situation in Turkey, but in many countries this stuff is easy to get your hands on. I can buy 50 of these ampoules for appr. EUR 10.


Here they also sell these ampoules, but about one third or fourth of them is always empty. :X And it is not a big deal to touch them while releasing the gas, because the release is rather slow, but once I opened the ampoule too fast and I got a frostbite on my middle finger, for like a week. :D

SM2 - 5-12-2012 at 08:20

The best way to buy nitrous is to buy a small NOX bottle, and have it filled. Sure, there is 1/%100'th H2s in it to act as a deterrent, but you can use it straight as is. Or fill your garbage with half a cup water, and a teaspoon or so of baking soda. Fill garbage bag, and shake vigorously for a couple of minutes. The soda shower will indeed remove most traces of the
H2S.

Endimion17 - 5-12-2012 at 11:27

Here's a relatively old thing I did for YouTube.
<iframe sandbox width="420" height="315" src="http://www.youtube.com/embed/OUHOjpbkAPY" frameborder="0" allowfullscreen></iframe>

It's one of those things that suffer greatly depending on the geometry of the reactants in the vessel, and the temperature distribution. The consequences can be disastrous, and were throughout the history of chemical plants.
I recommend only analytical purity ammonium nitrate in small batches, 5 g, more or less. Never let full decomposition take place in a test tube or similar vessel.

Eye protection is a must, and if you have a face shield, use it.

I did it with a recrystalized compound from a fertilizer, so it contained earth alkali nitrates which precipitate and can form a hotspot, so I was extremely careful. Such mixtures should never be heated even near full decomposition because a hotspot-initiated detonation is likely to occur. Don't even try, it's not funny at all. If you must use impure AN for making nitrous oxide, watch for the precipitate. As soon things start to go milky, stop.

And for the love of god, never use these as a heating device.


It has become increasingly common to see people on YouTube using these torches for heating glassware. It's EXTREMELY STUPID and can cause a disaster.

What happened with simple alcohol burners?
It's the "I want it NOW NOW NOW" attitude of kids today, that's what it is. I hate painfully slow experiments that require constant tending, too, but some things are not meant to be rushed that much.

garage chemist - 5-12-2012 at 12:44

I have also experimented with nitrous oxide production a long time ago and even compressed some of it into a gas cylinder using a fridge compressor. This was extremely dangerous because the oil of the compressor will form an explosive combination with the compressed N2O. It didn't explode because N2O needs quite a high temperature to start decomposing and oxidise combustible substances (around 600°C), which is not reached in the compressor during normal operation.
For compressing N2O, the oil inside the compressor would have to be completely removed and changed to an inert oil like Fomblin PFPE.

I found that N2O from ammonium nitrate always contains some NO2 and NO as well, and that the latter is not removed by washing the gas with NaOH solution. Washing with FeSO4 solution is required, and very good contact of the gas with the solution is a must, like in a washing bottle with sintered glass bubbler. I found this purification too laborious and unrelaiable to make this a practically useful preparation.

The method that Fleaker posted is much better, in my experience. After one NaOH wash, the N2O is entirely free of higher nitrogen oxides and smells the same as the gas from whipped cream capsules. This reaction produces a much purer gas than the decomposition of ammonium nitrate.
Brauer recommends to heat 10ml 73% HNO3 with 4g sulfamic acid. This is a large excess of HNO3. I wonder if less HNO3 can be used?

Fleaker, when using sulfamic acid to remove HNO3 from an AR solution, what temperature is used and does this not form ammonium ions through hydrolysis of the sulfamic acid which may form precipitates with certain precious metals?

shannon dove - 5-12-2012 at 13:15

Endimion17 makes it sound like ammonium nitrate can be detonated without a detonator. I thought it was easier for a camel to go through the eye of a needle than to detonate ammonium nitrate. Maybe there is a glimmer of hope that ammonium nitrate can be detonated without having to mess around with primary explosives.
I have read about massive quantities being detonated from fire, but Endimion17 makes it sound like smaller quantities might also be detonated this way.

Endimion17 - 5-12-2012 at 14:51

Quote: Originally posted by shannon dove  
Endimion17 makes it sound like ammonium nitrate can be detonated without a detonator. I thought it was easier for a camel to go through the eye of a needle than to detonate ammonium nitrate. Maybe there is a glimmer of hope that ammonium nitrate can be detonated without having to mess around with primary explosives.
I have read about massive quantities being detonated from fire, but Endimion17 makes it sound like smaller quantities might also be detonated this way.


No, I didn't make it sound like that. You just have trouble understanding what I've said, and obviously have a disregard (ignorancy?) for reaction vessel geometry and heat flow. It's chemical engineering, and it's much more complicated than just pure, small scale demonstration experiments.

If heated improperly, pure AN can form a molten pocket trapped between the vessel and the crust, resulting in a burst. If we're talking about a huge tank instead of a test tube, we have way more energy for a not much larger vessel and less heat conduction. Real detonation might occur and it's a well known example that has killed lots of people in the past.


Impure AN from a fertilizer contains ammonium nitrate and hydrates of calcium and magnesium nitrate.
I don't have enough data for magnesium nitrate (decomposition at 330 °C), but calcium nitrate tetrahydrate melts at 42.7 °C and starts to lose water by boiling at 132 °C, leaving a residue of anhydrous calcium nitrate that melts at 561 °C (let's leave possible eutectic scenario out). Ammonium nitrate decomposes by boiling at 170 °C.

Probably all the water will be lost by the time AN starts releasing nitrous oxide. Therefore you get more and more calcium nitrate per reaction volume. It touches the hot vessel walls and can form a residue and a hotspot. And it indeed does, because the exiting gas has more and more nitrogen dioxide in it as the decomposition proceeds. I've made a recrystalized product, so there were not many earth alkali nitrates inside, but nevertheless you can smell some NO2. It smells nice because the concentration is very low.

The products are calcium oxide and nitrogen dioxide. Calcium oxide is even worse with the whole residue caking and heat conduction issue and gives the mixture a milky appearance.

I tried to boil down several small amounts to see what will happen. Very small amounts boil off and you're left with a calcium nitrate (with oxide impurity) white residue which heats up quickly and decomposes violently to oxide and nitrogen dioxide (some oxide dust included).
The larger the sample, the more violent it is, and we're talking about 1 g, more or less. It's like a crackling puff.

Someone would want to try doing this with 100 g. Or would pack half of a kilogram in a vessel. Now imagine how violent that "puff" would be.

uzaymaymunu - 5-12-2012 at 17:37

Quote: Originally posted by Fleaker  
Isn't it just easier to make N2O from sulfamic acid and nitric acid and be left with pure sulfuric acid? It's like $2.50/kg of N2O.

We use sulfamic to destroy nitric acid residues in aqua regia, and because N2O is a gas, it's favored. Heck of a lot faster than boiling it down!


2.5$, really? I think it is more expensive than 2.5$
i will ask a chemical seller tomorrow.
Do anyone know any easy way to make sulfamic acid?
(easy to find reactives)
Quote: Originally posted by woelen  
You can also buy N2O for cream. It is sold OTC in metal ampoules, which easily can be ruptured. Each ampoule holds 8 grams of N2O and the gas can be released into a balloon. You only have to be very careful not to touch the ampoule immediately after release of the gas. The ampoule is cold, very cold and you certainly will have nasty frostbite when you touch it.

You could have a look for N2O ampoules in your area. I'm not sure about the situation in Turkey, but in many countries this stuff is easy to get your hands on. I can buy 50 of these ampoules for appr. EUR 10.


No one use this ampoules in turkey; i have never heard or seen. but i find only an online shop in turkey and it's so expensive 20€ ;)

shannon dove - 6-12-2012 at 04:55

It seems that Endimion17 is using self proclaimed superior intelligence to insult me. A lot of people on here do that. I suppose that nerdy science kids get picked on so much in school that they end up with a bad attitude.
anyway I was just trying to discuss the details of how ammonium nitrate can detonate from heat, I thought this has the potential to be a very interesting discussion.
And I do appreciate your information on the topic Endimion17, I just don't like the insults.

Poppy - 6-12-2012 at 15:31

Heating impure ammonium nitrate, the dirtiest you can get, from the reaction of calcium nitrate and ammonium sulphate, would not explode even pouring oil in. A flame emerged only when the torch was applied directly at the bottom of the container.
But closed containers are another insult...

ScienceSquirrel - 6-12-2012 at 18:30

It is not easy to say how any amount of ammonium nitrate will react when heated.
Small amounts, several grams, can decompose quite smoothly if heated steadily.
The reaction can be calmed by heating a mixture of ammonium sulphate and sodium or potassium nitrate or by heating ammonium nitrate and sand.
Kilo amounts of ammonium nitrate can run away, the heat of reaction is sufficient to cause yet more decomposition and if contained it can explode.
Amounts of about 25kg, particularly if soaked in diesel and stuck in a milk can with a couple of sticks of gelignite to provoke it will result in a big bang.
In tonne quantities, fire alone can result in transition from a violent fire to an explosion
http://en.wikipedia.org/wiki/Ammonium_nitrate_disasters

Poppy - 7-12-2012 at 05:05

From the exerts of Laser physics, a major outrun occurs when the stimulated emission surpasses the loss of the ressonator cavity. That is, at some point those vibrations destructive to chemical bonds will be predominant and etc...
That shoudn't happen specially with mixtures of diesel and AN because diesel dissipates rotational vibration energy. It needs a primary in other words, to detonate, or in some cases heating and applying a hard shock, might work, but temperature alone shouldn't raise such ressonance as to initiate DDT.

[Edited on 12-7-2012 by Poppy]

shannon dove - 7-12-2012 at 05:20

Is it possible to get a bridge wire to detonate ammonium nitrate the way it does petn? Maybe a long wire coiled in a mass of anfo? Maybe hitting the wire with more wattage than the bridge wire detonaters use?

ScienceSquirrel - 8-12-2012 at 17:25

Quote: Originally posted by Endimion17  
Here's a relatively old thing I did for YouTube.
<iframe sandbox width="420" height="315" src="http://www.youtube.com/embed/OUHOjpbkAPY" frameborder="0" allowfullscreen></iframe>

It's one of those things that suffer greatly depending on the geometry of the reactants in the vessel, and the temperature distribution. The consequences can be disastrous, and were throughout the history of chemical plants.
I recommend only analytical purity ammonium nitrate in small batches, 5 g, more or less. Never let full decomposition take place in a test tube or similar vessel.

Eye protection is a must, and if you have a face shield, use it.

I did it with a recrystalized compound from a fertilizer, so it contained earth alkali nitrates which precipitate and can form a hotspot, so I was extremely careful. Such mixtures should never be heated even near full decomposition because a hotspot-initiated detonation is likely to occur. Don't even try, it's not funny at all. If you must use impure AN for making nitrous oxide, watch for the precipitate. As soon things start to go milky, stop.

And for the love of god, never use these as a heating device.


It has become increasingly common to see people on YouTube using these torches for heating glassware. It's EXTREMELY STUPID and can cause a disaster.

What happened with simple alcohol burners?
It's the "I want it NOW NOW NOW" attitude of kids today, that's what it is. I hate painfully slow experiments that require constant tending, too, but some things are not meant to be rushed that much.


You can use a micro lamp as a heat source.
It has a collar like a Bunsen burner that allows you to throttle it back to produce softer flames.
I did a lot of chemistry with gas burners before electric heater, stirrers became generally available.
I still use one for general heating.
Keep your burner close and your fire extinguisher closer! -)

AndersHoveland - 9-12-2012 at 05:20

Quote: Originally posted by garage chemist  
This was extremely dangerous because the oil of the compressor will form an explosive combination with the compressed N2O. It didn't explode because N2O needs quite a high temperature to start decomposing and oxidise combustible substances (around 600°C), which is not reached in the compressor during normal operation.


From what I have read, these pressurised mixes can be shock-sensitive.
http://pubs.acs.org/doi/abs/10.1021/ac00069a028

Localised adiabatic pressure from fast moving contact points within the compressor can provide the necessary heating to initiate detonation.

uzaymaymunu - 12-12-2012 at 10:36

i bought sulfamic acid.
Quote:

Nitrous oxide can be made by heating a solution of sulfamic acid and nitric acid.
HNO3 + NH2SO3H → N2O + H2SO4 + H2O


how i can get N2O with this reaction ( temperature and steps) ?


EDIT!:

İ have just tried with home made nitric acid ( 2KNO3 + H2SO4 ---> HNO3 + K2SO4 ) i could not see any bubbles. Then I heated the mixture and it began to bubble up but it's not looking like effervescence. (i think just nitric acid boiled. isn't it?)

I washed the occuring gas with NaOH solution and clean gas collected in a balloon.

Finally i smelled gas but it was no smell. And i've tried to inhale but nothing happen.

Please tell me is there anyone tried this? And Where is the problem?

[Edited on 13-12-2012 by uzaymaymunu]

shannon dove - 13-12-2012 at 14:41

I would make absolutely, 100% for sure it is what you think it is before inhaling a mysterious gas.
Buy a mouse from a pet store, put him in a jar and see if the unknown gas makes him sick.
I thought it was supposed to use sulfamic acid instead of sulphuric acid?
Oh, I see you was just using sulphuric to make nitric acid.
I'm just learning how to edit.


[Edited on 13-12-2012 by shannon dove]

uzaymaymunu - 13-12-2012 at 16:04

Here a photo from yesterday...

kristofvagyok - 13-12-2012 at 16:11

Just an idea: but if the lye or that liquid what is in that gas washer sucks back to the boiling ammonium nitrate you will get really surprised. Go get something, maybe an empty bottle between the two other.

uzaymaymunu - 13-12-2012 at 16:36

Quote: Originally posted by kristofvagyok  
Just an idea: but if the lye or that liquid what is in that gas washer sucks back to the boiling ammonium nitrate you will get really surprised. Go get something, maybe an empty bottle between the two other.



That was not ammonium nitrate. Please read my previous message. I used sulfamic acid.

[Edited on 14-12-2012 by uzaymaymunu]

kristofvagyok - 13-12-2012 at 16:51

Quote: Originally posted by uzaymaymunu  

That was not ammonium nitrate. Please read my previous message. I used sulfamic acid.

Sorry for my quote.

But in this case I would say it again: use a buffer flask.

chemrox - 13-12-2012 at 21:51

Quote: Originally posted by Fleaker  
Isn't it just easier to make N2O from sulfamic acid and nitric acid and be left with pure sulfuric acid? It's like $2.50/kg of N2O.

We use sulfamic to destroy nitric acid residues in aqua regia, and because N2O is a gas, it's favored. Heck of a lot faster than boiling it down!


so what do you do? mix equivalents of the two? would you have to wash the N2O?

Are we talking about N2O or nitrous oxide?

uzaymaymunu - 14-12-2012 at 15:16

"Heating 4 g. NH2SO3H with 10 cc. previously boiled 73% HNO3 over a small flame produces approx. 1 l. of pure N2O with 100% yield. HNO3 of higher concn. causes violent development of N2O."

I think the key is "previously boiled"

[Edited on 14-12-2012 by uzaymaymunu]

AJKOER - 25-6-2013 at 06:05

Quote: Originally posted by uzaymaymunu  
@kristofvagyok, i will heat ammonium nitrate in erlenmayer bulb. and forming gases (nh3+ nitrogen oxides + N2O + nh4no3 vapour ) will go gas washing solutions. Finally the pure N2O will fill in plastic balloon :)
All of these will be in atmospheric pressure. So it will never get overpresured.


In my opinion, the potential significant danger of someone intentionally upon washing or accidentally inhaling the raw gas mix (as described above) is not from solely the NO gas and its formation of NO2. The latter acid gas may quickly produce a burning sensation that may adequately forewarn one to quickly stop inhaling.

My concern is a bit more subtle as NH3 + NO + NO2 (from O2 and NO) could form a fine smoke of NH4NO2. Source: Per Wikipedia (http://en.wikipedia.org/wiki/Ammonium_nitrite ): "Ammonium nitrite forms naturally in the air and can be prepared by the absorption of equal parts nitrogen dioxide and nitric oxide upon aqueous ammonia.[2]". In the case of dry NH3, the reaction has been given as follows:

NO2 + NO + 2 NH3 --> NH4NO2 + H2O + N2

Of importance, Ammonium nitrite is considered 'acutely toxic' (same source) upon ingestion, which could include inhalation of the dry powder.

Upon washing the NH4NO2 fine dust with aqueous Ferrous sulfate, one may simply produce a layer of the powder floating on the liquid. Bubbles of your 'pure' N2O could then be contaminated by the NH4NO2, or not, but my uncertainty suggests find another path like the previously discussed preparation via sulfamic acid and nitric acid.
-----------------------------------------------------------

Here is an alternate preparation that suffers also from the nitrite problem as well. To quote (see http://www.transtutors.com/chemistry-homework-help/s-and-p-b... ):

" i) Very active metals such as Mn, Mg, Ca, etc. give H2 on treatment with very dilute HNO3 (2%).

(ii) Less active metals like Cu, Hg, Ag, Pb etc. give NO with dil. HNO3 . Zinc, however, gives N2O with dil HNO3 and NH4NO3 with very dilute HNO3.

Zn + 10HNO3 ( dilute ) → 4Zn(NO3)2 + N2O + 5H2O "

Now, nitrate salts in the presence of Zinc (see http://www.microbelibrary.org/library/laboratory-test/3660-n... ) and perhaps just NO as well (see http://www.cee.mtu.edu/~reh/papers/pubs/non_Honrath/fischer9... ) may also introduce some nitrites. So this preparation route does not solve the potential nitrite contamination issue discussed above.

Also, the above reaction is not clean as varying concentrations of Nitric acid can produce varying products. For example:

Zn + 4 HNO3 (Conc) --> Zn(NO3)2 + 2 NO2 + 2 H2O

Now, for the record, I may be over stating the potential threat of Ammonium nitrite poisoning in these N2O preparations, but, at least, I won't both be dead and wrong.


[Edited on 25-6-2013 by AJKOER]