Bromine
Harmless
Posts: 45
Registered: 7-9-2006
Location: Slovenija
Member Is Offline
Mood: good
|
|
NH4NO2
Can be ammonium nitrite prepared by oxidizig concentrated ammonia solution by 30% hydrogen peroxide? This information i found somewere, i can't
remember right now.
|
|
|
woelen
Super Administrator
Posts: 7977
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
Ammonium nitrite is unstable. If you add NaNO2 to a solution of NH4Cl, then bubbles of N2 are produced, especially when the liquid is heated a little.
So, I expect the solid to be very unstable.
I expect that if you add concentrated H2O2 to concentrated ammonia solution, that the H2O2 will decompose quickly and that hardly any oxidation of
ammonia occurs. Some oxidation may occur, but if this happens, then I expect haseous N2 and/or N2O to escape, or maybe some nitrate remains in
solution, but I have strong doubts about all this.
|
|
|
guy
National Hazard
Posts: 982
Registered: 14-4-2004
Location: California, USA
Member Is Offline
Mood: Catalytic!
|
|
I read you can do it with NH3 and O3.
|
|
|
AJKOER
Radically Dubious
Posts: 3026
Registered: 7-5-2011
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by Bromine  | | Can be ammonium nitrite prepared by oxidizig concentrated ammonia solution by 30% hydrogen peroxide? This information i found somewere, i can't
remember right now. |
Yes, Ammonium nitrite can be prepared by oxidizing an ammonia solution with hydrogen peroxide.
On an old thread on Sciencemadness no less (see http://sciencemadness.org/talk/viewthread.php?tid=11781 author: Formatik), apparently the required catalyst include any of NaOH, Na2CO3, Zn dust,
Pt or Pd-H2.
Upon boiling (NH4OH + H2O2 + catalyst) the creation of NH4NO2 is apparently accomplished (a given reference is completely in German however). One can
perform a demo by adding a mineral acid which results in the evolution of NO and NO2.
2 NH4NO2 + H2SO4 --> (NH4)2SO4 + 2 HNO2
2 HNO2 --> NO + NO2 + H2O
Note, NH4NO2 is unstable (a two hour half-life, decomposes 60 to70 C) and is considered a high explosive (solutions are also sensitive) with limited
applications due to thermal and shock sensitivity.
Note, NH4NO2 is also considered to be acutely toxic.
Here is the complete quote by Formatik:
"The Ber. ref. from Hoppe-Seyler describes it. Namely, strong solutions of H2O2 with a few drops of NH4OH or solutions of ammonium carbonate (with or
without NaOH or Na2CO3) can be let to stand 24 hours without any nitrite formation occurring. But upon longer standing, even with a small amount of
hydroxide then nitrite forms. Nitrite also forms when a dilute solution of H2O2 is mixed with NH4OH and a little Na2CO3 and is evaporated over pure
conc. H2SO4 with a bell jar.
H2O2 forms (even in very dilute solutions) nitrite very rapidly, if the H2O2 solution is mixed with a few drops of NH4OH and a little NaOH or Na2CO3,
and this then boiled in a retort to a very small volume. They suggest this nitrite formation as a demonstration experiment because it is very quick to
do, and then after acidification of the colorless liquid with H2SO4, the HNO2 can be nicely be proven to be present."
CAUTION: The reader may note that the suggested preparation of NH4NO2, and the MSDS described thermal detonation properties of NH4NO2 (if applicable
to solutions also) appear to overlap. Hence, possible detonation may occur on following the described preparation route.
[Edited on 20-11-2011 by AJKOER]
[Edited on 20-11-2011 by AJKOER]
|
|
|
AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
see:
http://sciencemadness.org/talk/viewthread.php?tid=11781
| Quote: |
an interesting reaction from the literature of Marcellin Berthelot, dry ammonia gas reacts with the nitrogen dioxide and nitric oxide, at room
temperature,
(2)NO2 + (2)NO + (4)NH3 --> (2)NH4NO2 + (2)H2O + (2)N2
Solid ammonium nitrite inside a tube explodes if heated on a water bath to between 60-70degC. And the substance gradually decomposes at room
temperature, slower if cold, or faster in aqueous solutions, forming nitrogen gas.
|
| Quote: |
strong solutions of H2O2 with a few drops of NH4OH or solutions of ammonium carbonate (with or without NaOH or Na2CO3) can be let to stand 24 hours
without any nitrite formation occurring. But upon longer standing, even with a small amount of hydroxide then nitrite forms. Nitrite also forms when a
dilute solution of H2O2 is mixed with NH4OH and a little Na2CO3 and is evaporated over pure conc. H2SO4 with a bell jar.
H2O2 forms (even in very dilute solutions) nitrite very rapidly, if the H2O2 solution is mixed with a few drops of NH4OH and a little NaOH or Na2CO3,
and this then boiled in a retort to a very small volume. They suggest this nitrite formation as a demonstration experiment because it is very quick to
do, and then after acidification of the colorless liquid with H2SO4, the HNO2 can be nicely be proven to be present.
|
|
|
|
Formatik
National Hazard
Posts: 927
Registered: 25-3-2008
Member Is Offline
Mood: equilibrium
|
|
| Quote: Originally posted by AJKOER | | CAUTION: The reader may note that the suggested preparation of NH4NO2, and the MSDS described thermal detonation properties of NH4NO2 (if applicable
to solutions also) appear to overlap. Hence, possible detonation may occur on following the described preparation route. |
Ammonium nitrite in the aqueous phase is not thermally stable enough to survive being entirely boiled down. In fact, its decomposition in the aqueous
boiling state by mixing aq. nitrite with an ammonium salt is an old method of preparing nitrogen gas.
Those were some good finds on forming it from hydrogen peroxide, but unfortunately I've not seen these qualitative experiments transformed into a
workable synthesis. If I remember right, Gmelin has some good information references on its preparation using sodium nitrite as the starting point.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
