plante1999
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urea to ammonia to nitrate
I have read that urea + sodium hydroxide make sodium carbonate and ammonia , but i have a question , how can i convert the ammonia to nitrate ion.
I said this because already last month i can buy ammonium nitrate from instan cold pack but now i can only buy urea as a source of nitrogen.
[Edited on 14-5-2011 by plante1999]
I never asked for this.
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hyperkinetic
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Are you thinking of the Ostwald process?
http://en.wikipedia.org/wiki/Ostwald_process
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plante1999
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Yes , but for the catalisor does any other than Pt work ,i was thinking of new ceramic catalisor like Cr2O3, does anyone have tried the process?
I never asked for this.
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redox
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Are you asking how to convert ammonia to ammonium nitrate? Or are you asking how to convert ammonia gas to nitrate ion?
If it is the first, simply bubble ammonia into nitric acid.
If it is the second, the Ostwalt process could suffice. Burn ammonia in oxygen over platinum and rhodium catalysts, yielding nitric oxide and water.
The nitric oxide is further oxidized to nitrogen dioxide, which is dissolved in water or hydrogen peroxide. This then produces nitric acid, albeit
weak.
Distillation will concentrate to the 70% (?) azeotrope.
My quite small but growing Youtube Channel: http://www.youtube.com/user/RealChemLabs
Newest video: Synthesis of Chloroform
The difference between chemists and chemical engineers: Chemists use test tubes, chemical engineers use buckets. |
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hyperkinetic
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Google says:
"The kinetics of ammonia oxidation over oxides of manganese, cobalt, copper, iron and vanadium have been studied. The proposed reaction mechanism
involves oxygen adsorption (oxidation of the catalyst surface) and reduction of the surface with ammonia to form the reaction products. The latter
step consists of several stages involving the intermediate formation of nitroxyl and imide species. The interaction of imide with nitroxyl leads to
nitrogen while the reaction between two nitroxyls results in nitrous oxide. For this model rate equations have been deduced which describe the overall
process and the parallel reactions of the formation of N2 and N2O. These equations are shown to be in accordance with the experimental data obtained.
It has been found that the selectivity in mild oxidation (N2 formation) decreases and the selectivity in deep oxidation (N2O formation) grows with an
increase in the surface coverage with oxygen θ. The values of θ increase with the ratio of partial pressures of O2 to NH3 (PO2/PNH3) in the
reaction mixture. The governing role of θ has been supported by experiments in which catalysts were reduced with ammonia in the absence of O2 in
the gas phase.
The reaction mechanism involving the formation of N2, N2O and NO is also considered. The corresponding rate equations have been derived, and the
expected dependence of specificity on the reaction mixture composition and temperature has been examined."
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi...
That should be about as easy as purifying magnesium with a fractional still. 
Edit: There are threads on urea to Nitrate attempts
http://www.sciencemadness.org/talk/viewthread.php?tid=3986#p...
http://www.sciencemadness.org/talk/viewthread.php?tid=133#pi...
[Edited on 14-5-2011 by hyperkinetic]
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mnick12
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There are some species of nitro and nitrosobacter which are able to use urea directly as their nitrogen source instead of ammonia. I use a pet store
brand of aquarium microorganisms to make yummy nitrate water from ammonia and molasses for my hydroponic system. It is really simple the only thing
you have to take into account is the size of your system, the PH ( usually around 7.5-8.5) and ammonia %. Then all you do is add an airstone and a
couple ml of bacteria solution and in about a day all the ammonia is converted into nitrate.
bacteria rule!
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Melgar
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Yeah, I did this once with bacteria scraped from the bottom of my trash can and pee. Crude potassium nitrate, for way too much effort! Also, I got a
platinum/rhodium thermocouple wire from omega.com, and heated it up, then put it above a really concentrated ammonia solution. It glowed red for a
few minutes and converted a bunch of the ammonia to nitrate. I evaporated the solution and got a little bit of ammonium nitrate, again for way too
much effort. Gas-phase reactions blow. 
Later, I wised up and just bought a couple pounds of KNO3 off eBay, then mixed it with H2SO4 from a hardware store (the drain opener that is
double-sealed in jug inside a plastic bag) and distilled off the nitric acid.
[Edited on 5/17/11 by Melgar]
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AJKOER
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I found a recent paper that discusses the oxidation of urea to nitrates using KMnO4:
"A NOVEL METHOD FOR SYNTHESIS OF Cr2O3, MnO2, MoO3 AND WO3"
by Maomen S. Refat, Sadeek and Sadr
ABSTRACT:
"Cr2O3, MnO2, MoO3 and WO3 oxides were synthesized by a new reaction of urea with (K2CrO4 or K2Cr2O7),
KMnO4, Na2MoO4 and Na2WO4, respectively, in an aqueous media at ~ 85 oC. Infrared spectra, X-ray powder diffraction,
and microanalysis of the solid products, indicate the absence of urea, and the presence of oxides. A general
mechanism describing the formation of oxides and decomposition of urea is suggested."
A basic reaction of possible interest in our case is:
2KMnO4 + CH4N2O --> K2CO3 + 2MnO2 + NH3 + NO2 + 1/2H2
See threads on preparing KMnO4.
Again more work than necessary, but at least educational.
Attachment: NH3OXISNO2BYK2CR2O7.pdf (252kB)
This file has been downloaded 1389 times
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pesco
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I know it is an old thread, but I believe the interest is still out there.
If you don't need the nitrate ions immediately and can wait couple days to maybe couple weeks for large amount then use bacteria.
It can be done in number of ways. Best is a box with porous substrate for bacteria to have surface to live on and pump the urea mix through the bed.
I have done it in two ways depending on what I had at hand :
1) large(ish) container to hold solution, cut soda bottle to hold some media, airline tube run to the bottom of the soda bottle and pump air. Adjust
it in a way, that some liquid is expelled with air at the top, so you know there is flow thourgh the system
2) same as above, but aquarium pump instead of airpump and pump water on the top of the soda bottle with media. As the liquid splashes the O2
dissolves in it
Important is to provide cations for the NO3- to react with. I usually do it by dropping chunks of chalk of which I have
unlimited amount where I live.
Have accomplished transformation of 25kg bag of urea into nitrates in less than 2 weeks. Most of the urea didn't want to dissolve at once due to
liquid saturation, but it vanished in couple of days. Can be even faster if needed.
Speed depends on:
- volume of "reaction vessel"
- rate of air/water being pumped through it
- quality and amount of media - important is surface area, I use alfagrog/leca/keramzyt depending on which I have unused at the time
- temperature
- how mature and large is the population of Nitrosomonas and Nitrobacter in the reactor
- if you provide some food/energy for bacteria - sugar is OK, molasses even better, kitchen scraps are also great, but boiled/mashed better than
whole chunks, point is for them to decompose and provide feed in timely manner. Works without feeding bacteria, but with little feed the process is
way faster. Really tiny bit is need, around a teaspoon per 100L of solution.
Important is to prevent formation of anaerobic spots as denitrifying bacteria could find a habitat and they are pretty efficient of turning nitrate
into N2 what would reduce/ruin your yield.
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fx-991ex
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Good and very interesting.
Cody's lab use charcoal as porous material if my memory serve me well.
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Alkoholvergiftung
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Here is an script after Muntz und Laine it seems after ww1 they used in some countrys there process of making nitrates. Oh and better than peat would
be "natural pozzulana earth in cherry size grains."
oh and an CO2 rich athmosphere is good for the bacterias too. they can only assimilate carbon from co2. An chinese paper stated an atmosphre of 30%
oxygen ond 70% CO2 would be the best for nitrification. Not useful for us but not bad to know. 
Pesco: they thell small pumps for indoor plants for days when you not at home some have an chamber for fertilizer and you put an hoss in an bucket of
water. That would indeal if you like to put nutriens for the bacterias.
Attachment: SaltpeterBac.pdf (139kB)
This file has been downloaded 10 times
[Edited on 23-12-2024 by Alkoholvergiftung]
[Edited on 23-12-2024 by Alkoholvergiftung]
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pesco
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Charcoal will do. Most of the time I use alfagrog since I do have bunch of aquariums and aquaponic system in which I use alfagrog and leca and keramzyt in filters as
nitrification/denitrification beds.
Ammonia and nitrites are poisonous to fish, but luckily the nitrification of ammonia and nitrite to much less harmful nitrate is very efficient once
you provide substrate for bacteria to live on and lots of oxygen.
To get rid of nitrates from aquariums/ponds once can replace water, but I always opposed as plain waste of water. Instead I am using denitrification
system. The setup is exactly the same as nitrification beds with one difference - it is anoxic. In anoxic environment different bacteria convert
nitrates to N2.
When I had no urea available I used urine and I placer container full of charcoal on top of the nitrate production setup. That eliminated and aroma,
there was not even a hint of a smell.
For the reason above if you make contraption for nitrates production make sure not to have any anoxic spots in the setup or you will loose your
product.
The bacteria do not need a lot of food. to be honest what is already in tap/pond water should be more than enough. I do occasionally add a bit of
sugar, crushed slice of sweet fruit or even handful of dirt or muck from aquarium filter. Mostly for good measure rather than due to desperate need
There is absolutely no need for any store bought "seeder packs" of bacteria. The bacteria are everywhere including air. when starting new setup it is
good to add pinch of dirt/filter much as it provides some nutrients and speeds up colonization by bacteria.
The nitrates produced I use for nitric acid production when needed for experimentation, silver refining etc. and for fertilizing veggie plots or
hydroponic beds when fish do not produce enough goodies for plants
Chemical means for nitrate production are fun, on test tube scale, but for production of larger amounts of nitrates nothing beats the bacteria in
terms of efficiency, easiness and cost.
The whole setup is old fashioned "nitre bed" on steroids
[Edited on 23-12-2024 by pesco]
[Edited on 23-12-2024 by pesco]
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Sir_Gawain
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Codyslab recently posted a video where he builds a bioreactor to convert urea to nitrate. Sort of like a fancy nitre bed.
“Alchemy is trying to turn things yellow; chemistry is trying to avoid things turning yellow.” -Tom deP.
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pesco
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Just watched.
Excellent video.
Exactly such thing I am running for more than 20 years now
When spring comes I'll take some photos and do a writeup. Might be handy for some people. Maybe a video ?
Based on experience few adjustments of Cody's setup:
- you can fill the barrel with substrate. Cody is using charcoal, I am using different stuff. I never fill the barrel with substrate, but make a tray
with it if pumping water or bottle/pipe if submerged and pumping air. If you fill the barrel with substrate then in case of power loss and it goes
anoxic you wont lose any nitrifying bacteria (they will just go dormant), but you are running a risk of loosing a lot of product if the substrate gets
colonised by denitrifying bacteria.
- I drop a little of limestone into the barrel. Bottom not even covered. Most of my limestone is mixed with the substrate. That way there is no anoxic
environment on the bottom of the barrel in between chunks of limestone.
- the nitrifying bacteria are most efficient at pH around 8 and limestone buffers to that level with ease if its mixed with substrate in a bed. If you
just drop some limestone to the barrel you might struggle to keep the pH at optimum level
- optimum temperature is around 30°C. I keep it in a greenhouse. No thermostat and temperature is within 20-30°C depending on time of the year.
Also, as side benefit, large container with liquid is great temperature buffer for the greenhouse
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Alkoholvergiftung
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You can also add some Gyps it is an good buffer free ammonium will get bound as sulfate in ph dosnt rise, and no ammonium loses to evaporation into
the air.
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