darkflame89
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possible chemical formula of fertiliser
As I can't find any ammonia solution anywhere down here in Singapore, I have decided to produce some of it from ammonium salts and sodium
hydroxide. Ah, but unfortunately, the fertilisers that are sold do not state their chemical formulas. All I see is the content of specific
nutrients(like nitrogen, phosphorus, blah, blah).
There is one type of fertiliser in my house that says gives nitrogen to the plants. Now, is it save to conclude that the fertiliser is probably
ammonium nitrate?
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chemoleo
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Well, if you are not sure, you might just as well try it. Add NaOH to the fertiliser, and drop in water. YOu should notice the ammonia smell
immediately.
In principle you could then distill this, and collect the NH3/H2O vapours in an icecool flask by bubbling it thru water. I dont know how well NH3
vapours dissolve though, so be prepared to use good ventilation. Un-dissolved NH3 could be absorbed in another collector flask in *dilute* acid.
[Edited on 8-3-2004 by chemoleo]
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Turel
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No
It is not safe to assume that the fertillizer contains pure ammonium nitrate. But it will contain ammonium sulfate and or phosphate, with near 100%
certainty on this one.
It likely contains some KNO3 in it, and disodium phosphate as well. Adding NaOH will evolve ammonia gas, and it will be quite strong, so don't
inhale strongly. The majority of the fertillizer cation is evenly split between potassium and ammonium ions in most cases.
-T
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axehandle
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If you're really deperate, and don't mind working with high voltages, try the Haber-Bosch process in a small scale.
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Turel
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Pressure
Haber processes use high pressure and heat to combine H2 and N2, not electricity. N2 reacts with H2 under heat and pressure, and O2 under potential.
At high pressure and temperature, H radicals exist, and readily attack the nitrogen lone pairs in N2, resulting in bond reduction. Once HN=NH is
produced, the next reactions occur very rapidly, reducing to hydrazine and then ammonia. Hydrazine is a byproduct of the Haber process.
Is Haber-Bosch the variation employing metal catalysis, forming intermediate nitrides for the H2 to attack?
In oxidation, potential is used due to nitrogen's inherent electronegativity. It is easy for several thousand volts to strip an electron off of
N2, leaving it open to attack O2 diradicals. The process evolves much heat because N2+ has shorter bond lengths than N2, emitting energy in the form
of heat in addition to the electrical charge generated heat.
N2O is a byproduct of this process, from N+ attack on NO, but this easily decomposes at the high temps to O and N2.
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Polverone
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another possibility
Urea may be a component of these fertilizers. This too will liberate NH3 with NaOH, but the reaction isn't as rapid as with an ammonium salt.
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Organikum
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Anyways, ammonia will be liberated and if the reaction flask is connected by an plastictube to a second flask containing water and both flasks are
rather airtight the ammonia will be sucked up by the water rapidly and almost no smell will evolve.
The extreme affinity of ammonia to water is wellknown, so this seems to me a favorable and easy way to get aqueous ammonia solution without too much
hassle and - more important here - by keeping the obnoxious smell down as far as any possible.
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hodges
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| Quote: | Originally posted by Organikum
Anyways, ammonia will be liberated and if the reaction flask is connected by an plastictube to a second flask containing water and both flasks are
rather airtight the ammonia will be sucked up by the water rapidly and almost no smell will evolve.
The extreme affinity of ammonia to water is wellknown, so this seems to me a favorable and easy way to get aqueous ammonia solution without too much
hassle and - more important here - by keeping the obnoxious smell down as far as any possible. |
Unless there's a one-way valve, won't water get sucked from the second flask back into the first flask? I'm assuming the outlet tube
is under the water.
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Organikum
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Your assumption is wrong.
The outlet tube is NOT under water as the affinity of ammonia to water is so strong that this would generate suckback.
Sorry - I forgot to mention this explicitely, my bad, I apologize.
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Marvin
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Arc process for nitric oxide is best thought of as a thermal equilibrium process, rather than one involving excited states. Thousands of volts are
certainly not required, just a good way to get 3000 kelvin.
Haber Bosch process is the usual N2/H2/Activated Fe ammonia process. High pressure drives the equilibrium far enough toward completion to be worth
the while (at 200atm to 1kbar), the heat is purely for kinetic reasons. High heat actually drives the reaction backwards. Haber made it work on a
small scale, but it took an international effort to solve the technical problems of getting it to work industrially. High pressure, high temperature
and hydrogen gas arnt easy to work with in combination.
Edit - forgot the suggestion that made me reply in the first place. If you make a note of the NPK values for the fertilisers you can get, you can
usually guess correctly what they are made of, and which ones to simply avoid. Try listing the values here.
[Edited on 9-3-2004 by Marvin]
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darkflame89
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Ah, ok, i might as well state my overall purpose for the ammonia. OK, i want to obtain this solution in which there are copper tetraamine(II) ions.
This is so that i can dissolve paper in it. This 'syrup'can then be passed thru dilute sulphuric acid so that i can produce a strip of
rayon, which is a polymer of cellulose
Ignis ubique latet, naturam amplectitur omnem.
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