Sciencemadness Discussion Board

How to separate AN and urea?

testimento - 11-7-2013 at 01:34

Ive got a solution of mostly urea and ammonium nitrate, how could they be separated? Their solubility is similar to water and most solvents. I'd need them both as they are, so reacting them with ex. NaOH wouldn't be what Im looking for.

I read that AN wont go into acetone but urea will. Is this true, gonna test it?

<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: merged sequential posts]

[Edited on 7/12/13 by bfesser]

madcedar - 12-7-2013 at 03:05

Try methanol, ammonium nitrate is slightly soluble in it:
http://www.sciencelab.com/msds.php?msdsId=9927336

Urea is soluble at about 160 g/l (I guess at room temperature)
http://www.sigmaaldrich.com/etc/medialib/docs/Sigma/Product_Information_Sheet/1/u5378pis.Par.0001.File.tmp/u5378pis.pdf

Manifest - 13-7-2013 at 03:15

Quote: Originally posted by madcedar  


Urea is soluble at about 160 g/l (I guess at room temperature)



In water?

Dariusrussell - 13-7-2013 at 13:34

madcedar means the Urea is soluble in the methanol, while the ammonium nitrate is only slightly soluble in methanol.

testimento - 13-7-2013 at 22:48

Yes I've heard that too from couple of sources, so I've got to try it. But I also have heard that the solubility difference is quite a little, so this is why i'm a little sceptic about it.

testimento - 16-7-2013 at 11:43

I cooked off the water from the fertilizer, totaling 20 liters of liquid. A cake crystallized out of the liquid when half was boiled off, and I sand filtered it on top of a cloth at 99C temperature to obtain a potful of some crystals, I suspect they are phosphates, maybe some urea and some other gunk. A browny liquid was put over burner again to obtain dark brown liquid, which was let for cooling and a mass of white stuff crystallized out, probably containing mostly AN and urea. I'll dry them carefully with oven and find out the acetone and methanol separation methods soon and let you know what I've got.

Sand filters are quite awesome separating all kind of turbid and dirty liquids. I got a bucket of glue-like paste from the filter, and only crystal clear, little yellowish liquid came through, no suspensic or colloid any at all. Just by a single pass through only 5cm layer of fine sand.

testimento - 30-7-2013 at 14:18

Couple of routes (NOT BALANCED):

Urea + AN + NaOH = NH3 + CO2 + NaNO3 + H2O

NaNO3 + H2SO4 = HNO3

HNO3 + NH3 = NH4NO3

____


I'd prefer the first since it's supposed to decrease the amount of H2SO4 wasted in the process and leads to mostly full recover of NH3 as a gas from the mixture.

This would, of course, need a large supply of sulfuric acid because it's tragically wasted in this process.

Glycerin will absorb as much as 500g/l of urea, but IDK about the AN solubility. The separation of glycerin from urea will be PITA though.

Another method would be, of course, to recycle the batch with HNO3:

Urea + AN + HNO3 = UNAN

UNAN + H2SO4 = HNO3 + NH3

>>>

This would have only the outcome that the whole batch is turned into nitrates which could be used for nitration process or an energetic compound as self.

The only major problem in this is that I dont actually need nitrates but ammonia and urea.. :D

testimento's Second Warning

bfesser - 30-7-2013 at 15:51

<strong>testimento</strong>, please, edit your post to balance those equations, and try using the subscript button (<img src="./images/xpblue/bb_subscript.gif" />;) for the numbers in chemical formul&aelig; (e.g. NH<sub>3</sub>;). "AN" is <em>not</em> ammonium nitrate in a reaction equation, and = is not a substitute for --> or &rarr;. <em>This is a science forum; notation is important.</em> There's no excuse for the level of laziness and disregard for scientific conventions that you've repeatedly demonstrated. <u>Consider this another warning.</u> (Your second, by my count.) If you continue to be a k3wl who's only interested in non-scientific industrial scale production of explosives, there will likely be consequences. Perhaps another website would be a better fit for you&hellip;

madcedar - 3-10-2013 at 04:05

Quote: Originally posted by testimento  
... I read that AN wont go into acetone but urea will. Is this true, gonna test it?


Searching MSDS's on the Internet gives conflicting information regarding the solubility of ammonium nitrate in acetone. Some say that it's soluble and others say that it's insoluble. I decided to test this myself with about 1 g of ammonium nitrate and 20 ml of acetone. I confirmed the ammonium nitrate is insoluble in acetone.

Then I dissolved 1 g of ammonium nitrate in about 1 ml of water and then added about 20 ml of acetone. The ammonium nitrate immediately fell out of solution.

I'm pretty sure urea is soluble in acetone but you'll have to test/search this out for yourself.

[Edited on 3-10-2013 by madcedar]

Endo - 3-10-2013 at 06:16

http://en.wikipedia.org/wiki/Hydrogen_peroxide_-_urea

Fantasma4500 - 3-10-2013 at 07:58

urea and H2O2 might be the idea.. if this is for energetic purposes i'd say surely that you just go with adding some HNO3 to the whole thing.. (:
UN is excellent for the purpose.. excellent..

testimento - 25-10-2013 at 19:48

The H2O2 method is far too expensive and H2O2 is not available for me at all in this country. I have thought the idea of UN, but this is not going for energetic but a reagent use. The purpose is to acquire ammonia gas and calcium nitrate.

I haven't been even yet able to find a method to separate the stuffs. My original idea was to react the ammonium nitrate - alongside with the urea - with calcium hydroxide in order to make calcium nitrate and acquire the ammonia gas from it.

I haven't been neither able to find any data however, how will the calcium hydroxide react with the urea? The residual calcium nitrate should be heated up to 650C to get the NO2 off from it, so, the urea and it's decomposition products(biuret, triuret, cyanuric acid, melamine) will all decompose within good time before that temp (360C highest decomp. for cyanuric acid), so they could be theoretically driven off with raw heat, although, would the calcium nitrate cause some problems at that temp with those items? I wouldn'd want it to deflagrate or detonate by any means..

The urea is quite an irritating compound.

CO(NH2)2 + Ca(OH)2 + H2O = ??? (Speculation(wish): CaCO3 + 2 NH3 + or would there be reaction at all?)

This looks absolutely too simple to carry out actually this way and one oxygen will lack the reaction as whole, so....

I cannot find any information what urea will do when mixed with alkali, so I expect it won't do anything. So, if there will be calcium nitrate and urea, they could be heated up to 175C which will release ammonia as gas and form cyanuric acid, which could be filtered out from calcium nitrate.

Hmm..
Quote:
If you add sodium hydroxide solution to an unknown organic compound, and it gives off ammonia on heating (but not immediately in the cold), then it is an amide.


[Edited on 26-10-2013 by testimento]

vulture - 26-10-2013 at 04:51

Quote:

I cannot find any information what urea will do when mixed with alkali, so I expect it won't do anything.


You would be wrong: http://www.sciencemadness.org/talk/viewthread.php?tid=19575

Please perform some research before posting, this link was found in a 10s google search.

bismuthate - 26-10-2013 at 08:56

Well you could just heat the solid mixture until decomposition.
Also
http://www.sciencemadness.org/talk/viewthread.php?tid=14525

[Edited on 26-10-2013 by bismuthate]

[Edited on 26-10-2013 by bismuthate]

[Edited on 26-10-2013 by bismuthate]

testimento - 26-10-2013 at 10:55

That was my original plan, since after calcium hydroxide application there will be calcium hydroxide, calcium nitrate and what is left of urea, and urea will decompose through cyanuric acid to isocyanide and other stuff, if it's not consumed by the hydroxide on the way. Only risk is that will urea, cyanuric acid, melamine and isocyanic acid react with calcium nitrate.

Sulfuric acid method would be nice, as long as I'd have some available.