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
|
|
N2O5 from UV-light on NO2
Dinitrogen pentoxide is a powerful nitrating agent, which exists as an unstable explosive crystalline substance that gradually and spontaneously
decomposes at room temperature after around two days. As dinitrogen pentoxide is the acid anhydride of nitric acid, it is a much stronger
dehydrating agent than even 100% concentrated nitric acid. Indeed, dinitrogen pentoxide could be added to 98% nitric acid to raise it to 100%
concentration if desired.
Two articles mention that N2O5 can be formed from nitrogen dioxide exposed to 300-400nm.
The beam of UV light should pass through the vessel of nitrogen dioxide as a beam, so that the solid N2O5 that forms can collect below, and not be
exposed to more UV light that would cause it to decompose back.
The nitrogen dioxide appears to photolyse according to the following equation:
4 NO2 + uv --> N2O + N2O5
This should really not be surprising, because it is also known that electric discharge through air can create traces of N2O5, first by forming NO2,
then by forming ozone from the oxygen, and finally by the spontaneous oxidation of the NO2 by the ozone which has already been produced.
2 NO2 + O3 --> N2O5 + O2
Ozone can alternatively be produced by exposing oxygen to UV light shorter than 200nm. The highest ozone concentration that can be produced by 185-nm
UV lamp is 0.2 percent by weight. Corona electric discharge can produce concentrations up to 2 percent.
"Photolysis of nitrogen dioxide to produce transient atomic oxygen, nitrogen trioxide (NO3), and dinitrogen pentoxide (N2O5)"
Alan B. Harker, H. S. Johnston
J. Phys. Chem., 1973, 77 (9), pp 1153–1156
"Disproportionation of nitric oxide at high pressure"
Stephan F. Agnew, B. I. Swanson, L. H. Jones, R. L. Mills
J. Phys. Chem., 1985, 89 (9), pp 1678–1682
Not really sure how practical this route would be for preparing nitric acid, as I suspect that the quantities of N2O5 produced from these methods are
not very much.
Some investigation has been carried out using N2O5 dissolved in pressurised liquid CO2 as a nitrating agent. It is quite feasible for an amateur
hobbyist to liquify carbon dioxide: http://www.sciencemadness.org/talk/viewthread.php?tid=17500
|
|
|
Ral123
National Hazard
Posts: 735
Registered: 31-12-2011
Member Is Offline
Mood: No Mood
|
|
I see most of the use of N2O5 for rdx, for other things the sulfiric acid is enriched with SO3. If there's a way to to dehydrate HNO3 and recycle
P2O5?
|
|
|
Adas
National Hazard
Posts: 711
Registered: 21-9-2011
Location: Slovakia
Member Is Offline
Mood: Sensitive to shock and friction
|
|
Quote: Originally posted by Ral123  | | I see most of the use of N2O5 for rdx, for other things the sulfiric acid is enriched with SO3. If there's a way to to dehydrate HNO3 and recycle
P2O5? |
You can not recycle P2O5 unless you form salt of phosphoric acid and distill it with carbon (high temps)
Rest In Pieces!
|
|
|
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
|
|
| Quote: |
It has been demonstrated that a dielectric packed pellet-bed plasma reactor operating on a mixture of NO2 in air at atmospheric pressure can be used
as an efficient method for the synthesis of dinitrogen pentoxide, N2O5. The reactor is packed with glass beads and operates at high frequency (10-13
kHz) and high voltage (peak <30 kV). Typically, the energy density is 38 J per liter and 45 ppm of NO2 is converted into 53 ppm of N2O5. The
synthesis of N2O5 is found to be plasma-assisted in the sense that sources of nitrogen in addition to the initial NO2 are converted into N2O5 by the
plasma. There is an energy cost of roughly 180 eV for every molecule of N2O5 produced. The possible role played by surface and heterogeneous effects
in the pellet bed reactor is considered. |
|
|
|
caterpillar
Hazard to Others
Posts: 472
Registered: 8-1-2012
Member Is Offline
Mood: No Mood
|
|
Yeah, but what does it means for us? There are much things, that can be realized in a big plant, but not in a poorly equipped lab (or in a kitchen).
Do you really think, that dinitrogen pentoxide can explode? I rather doubt about it. The last chapter in the nice book, written by Jai Prakash Agraval
and Robert Hodgson is named "A dinitrogen pentoxide- an eco-friendly nitrating agent".
Women are more perilous sometimes, than any hi explosive.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
