Sciencemadness Discussion Board

Isolation of urea from urine!

chemoleo - 11-8-2004 at 15:33

No, I am not kidding!

I have always been interested in the chemicals the body produces/excretes, and urea is one of them!
Of course, urea is mostly easily available, but not everywhere. So there are ways of obtaining it yourself, from a chemical synthesiser called your own body ;)

Urea is of course an ancient, well studied chemical, in fact it was discovered over 230 years ago, and Friedrich Woehler determined that urea could also be synthesised from inorganic chemicals, i.e. by the reaction of potassium cyanate with ammonium sulfate (1828).

The original discovery of urea was by Hilaire Marin Rouelle in 1773, who obtained it by boiling urea dry and obtaining a white residue (which later proved to be identical with Woehlers reaction products - disproving the idea that the chemistry of the living is radically different from inanimate matter)

Unfortunately, simply boiling down urine doesnt quite satisfy anyone, as it still contains certain quantities of salt, creatine, ureic acid, proteins etc.

Per day, about 1.5 - 2 litres are excreted, consisting of 95% of water. The rest (in grams per day consists of)

# 25 g urea
# 1 g uric acid (metabolic endproduct of purines from DNA)
# 1.5 g creatinine (derived from creatine phosphate, the muscle booster)
# 10 g of salts, mainly NaCl
# 3 g of phosphates, citric acid, oxalic acid,
# milligrams of proteins, and urochromen, which is the compound giving rise to the yellow colour of urine.

Now, looking at this information, what could be the best way of isolating urea from it?

How about this:

1. Collect urine for about a week, one should get about 10 litres. Needless to say, urine is STERILE to start off with. Preferably though, after each urine addition, the solution should be simply boiled to keep it sterile. Otherwise, just literally pee into a sterile pot with lid, and keep it at 4 deg C for the rest of the week. I dont think bacterial contamination should be a problem then (unless your have a medical condition, where bacteria are excreted through your urinary tracts)
2. AFter a week, boil down the urine, until a solid mass is obtained (from the above table, it should way about 300 grams. Do this outside, unless you want 10 litres of water condensing on your windows
3. That's when things become interesting. You want to get rid of salts (primarily), and phosphates. At this point there is no easy way to get rid of the creatinine, and the ureic acid. Proteins aren't much to worry about anyway, as conc. are very low.
So - I checked - urea is soluble in ethanol, at 50 g / l, @ 20 degC . Probably a lot more is soluble at higher temperatures. In water, it dissolves at >1500 g/litre, so very highly soluble. I'd try to dissolve the urine residue in an excess of cheap industrial ethanol (doesnt matter if it contains other things), which would mean, around 3 litres, if you heat the ethanol up a little (no open flames ok). All the inorganic stuff (salts etc) are barely soluble in ehtanol, so they should remain precipitated.
4. Filter off the remainder, and boil of the ethanolic solution of urea (with a small amount of creatinine potentially) down to a few hundred ml's, or even to dryness. If you distill, you can obviously recycle the ethanol, although it may prove to be a pain to recycle such large amounts, considering that ethanol is cheap anyhow.
5. Alternatively, once you boiled down the ethanolic solution of urea to a few hundred ml, you could add HCl (conc) or H2SO4, and precipitate urea as the respective salt (which is surely insoluble in ethanol). The salt can be turned back into urea with the appropriate amount of NaOH.

What do you think? Sure this is a very simple way of purifying urea, and of course if you had all the reagents, one could get extremely high purities.
At least, this way, one gets about 200 g of urea, straight from urine, with the only expense of 3 litres of industrial ethanol.


[Edited on 10-1-2010 by chemoleo]

Polverone - 11-8-2004 at 17:13

I'm pretty sure that the "established" method of isolating urea from urine is to boil down the urine to concentrate the solution, then add nitric acid. Urea nitrate is relatively insoluble and precipitates. I think Megalomania's chem lab had a more exact procedure for this. Then you can take that small amount of solid and treat it with NaOH and ethanol to get the urea back.

I like this method because it should sharply separate urea from not-urea, and may require less energy (less forced evaporation). Urea oxalate is also fairly insoluble and can be precipitated from an aqueous solution containing urea.

Edit: sodium oxalate is isn't very soluble either, so I suppose HNO3 is the way to go.

[Edited on 8-12-2004 by Polverone]

I am a fish - 12-8-2004 at 07:06

I know this forum advocates mad science, but isn't collecting urine going a bit too far? Amateur chemistry is a hard enough hobby to justify already, without having jars of urine to explain.

Then again, there are worse things you can do with it...

chemoleo - 12-8-2004 at 08:18

To be honest, I don't think it goes too far at all.

Let me remind you that many diseases are diagnosed by analysing urine. Which means the person concerned has to fill a cup with it, and pass it on to the laboratory, who analyses it down to the last molecule. People are handling it every day and don't complain it goes to far. Oh, you may argue they do it because it's necessary, while purifying urea from urine isn't. Is that how you define 'going too far', however? Whether something is necessary or not?

By the way, in practical biochemistry classes, we analysed our very own urine for vitamin C content - which wasn't strictly necessary - and yet noone complained doing it.

Also, let me remind you that in biochemistry, urine is routinely used to purify certain enzymes. In fact, I worked with enzymes directly isolated from my own urine. So what? It's natural, and by no means sick, disgusting or dirty. Your blood is equally dirty (indeed your lymph fluids consist of less concentrated urinal fluids).
How is it different to isolate urea from urine, or glycogen from liver, cysteine from wool, or oxalic acid from rhubarb? The only difference that these are excretions - but it's still as natural or unnatural as anything else. What's the big deal?

Hmm - am I lacking perspective or something?
I thought that the idea/philosophy behind this, in essence, is no different to a lot of other chemical problems/purifications - if you ignore this totally unreasonable 'disgust' factor - totally unreasonable because urine is sterile, contains about 200 compounds, und doesnt even smell, unlike pancreatic enzymes / bile and such - which have been analysed to death just as well.
Again - where's the big deal? And what's this to do with the link ?(pee drinking - what the hell) :(

[Edited on 12-8-2004 by chemoleo]

ziqquratu - 12-8-2004 at 14:37

I'd just like to say, urea is NOT inherently sterile even in healthy people. First of all, it is not that unusual for a few bacteria to be present in the bladder (although these are generally transient - if they colonise, you get an infection).

Secondly, urine is typically contaminated as it leaves the body, as bacteria are relatively common in the urethra, certainly towards the end.

That's why when you give a urine sample for disease testing the doctor will ask for a "mid-stream" sample - you will pee about a third of the contents of your bladder, stop, stick the cup under there, fill the cup and then finish off. THe first third is designed to (hopefully) wash away any transient bacteria.

Diagnosis of urinary tract infections is actually a statistical thing - if you detect a single live bacterium in the blood, for example, it is immediately considered an infection. But because of the relatively common contamination of urine, you have to have more than a cecrtain threshold level present in the sample to be considered an infection.

Thought somone might like to know this... trust me, nobody needs to work with semi=fermented urine samples (it's FAR from pleasant!!)

chemoleo - 12-8-2004 at 14:57

Of course, semi-fermented urine samples aren't pleasant. That's why I suggested boiling them.
But then, is the smell of ammonia pleasant? Surely not. Except, in the former case, ammonia is produced bacterially...

Anyway - the debate is not so much about the issue whether it's sterile or not (and I agree about your mid-stream sample), but simply whether this particular case is 'science that goes too far'.
And I just happened to disagree on that :) - if anything, I'd say, the making of highly toxic nerve gases is science that goes to far, at least for the amateur chemist!

Geomancer - 12-8-2004 at 17:02

Actually, I found the link somewhat interesting, although it failed to substantiate most of its positive claims. For example, I've always been taught that ingesting urine is counterproductive in preventing dehydration. They even intimate that "urine therapy" can be usefull in treating gout, a disease caused by excessive levels of uric acid!

S.C. Wack - 12-8-2004 at 17:04

US5659080 from the E&W archives:
In a 100 ml beaker was placed a solution of 50 grams of 33% diluted nitric acid, and to this solution was added 14 grams of urea in small portions while stirring vigorously. For this period of time, since the temperature does not show any rise practically, this reaction can be carried out in room temperature and is not necessary to be kept cool. Immediately urea nitrate resulted as crystals. Having been allowed to stand for 10 minutes, the mixture was filtered to collect the crystals. This crystals were washed with a little amount of water to remove the solution well and were then dried in a desiccator under vacuum. The yield resulted in 23.8 grams of urea nitrate (97% yield), whose melting point was measured to be 162.degree. C.

Urea and uric acid extraction from urine was good enough for Wieland's revision of Gattermann. It was isolated using colorless 70% HNO3. All the other old refs use the conc. acid as well. And all use BaCO3, K2CO3, or KHCO3 to give the metal nitrate.

The oxalate was made with hot satd soln of oxalic acid and syrupy urine. Like the nitrate it is not very soluble in excess of the acid. The oxalate is decomposed with CaCO3 suspension. This has the advantage of forming insoluble Ca oxalate, and the aqueous solution is filtered and evaporated.

Decolorizing was done with charcoal or boiling H2O2.

chloric1 - 30-11-2008 at 17:18

Using nitric acid to separate urea is quite a waste of HNO3.
Quote:

Edit: sodium oxalate is isn't very soluble either, so I suppose HNO3 is the way to go.


Yes but potassium oxalate is soluble and oxalic acid is more readily available and cheap. The potassium oxalate is a usefull byproduct for other syntheses.

Did some looking around and it appears that most of the sources state that the urea oxalate would best be hydrolysized by calcium carbonate effecting the precipitation of calcium oxalate leaving the urea in solution. Urea is a really weak base so I see little difficulty here. Will try sometime but I am leaving the country for two months so experimental results will be delayed.

[Edited on 12/1/2008 by chloric1]

Mr. Wizard - 1-12-2008 at 07:43

Urine was used for many things in past times. Aged urine even had a name: lant.

Vogelzang - 19-4-2009 at 19:16

Have you considered using the urine to make red phosphorus?

hissingnoise - 20-4-2009 at 05:19

Whew! Boiling down large volumes of malodorous liquid---great way to "piss" off the neighbours. . .
And large volumes would surely be needed.

Increasing the yield:

U235 - 8-5-2009 at 07:55

BTW, you can increase the amount of urea excreted: by eating more protein for a few days. The daily need is quite constant except when you have wounds or infections, or while training of muscles---about one gram per kg body mass. Any more than this is made to urea (in the urea cycle) and excreted.

That doesn't mean *any amount more than 1g/kg is excreted as urea. Huge amounts are probably not even digested and pass with the stool (or is then rather eaten by intestinal bacteria).

I would also put in a slight caveat on too much protein over long time periods: it's a risk factor for getting struvit kidney stones.

hissingnoise - 8-5-2009 at 08:26

I'm on a diet of greens---need some KNO3. . .

ScienceSquirrel - 18-5-2009 at 09:29

Technical grade urea ca 98% is readily available as a fertiliser almost everywhere.
A couple of recrystallisations would result in very high purity material.
There are a few interesting derivatives that can be prepared eg the nitrate, oxalate etc and you can make acetamide, benzamide etc using it.
Isolating urea from urine might be interesting on a small scale but it would use large amounts of reagents that would cost more than the urea if scaled up.

grndpndr - 1-9-2009 at 06:04

$12.95 17# 46-0-0 . the ancients used human urine to brush thier teeth and whiten them,yum yum.Of course the ammonia used to whiten the teeth removed the hard outer
layer of dentine.One would think cat urine with its ammonia content would work well to promote severe dental decay.:D
I believ ammonia(in a more palatable form) was used for this purpose until the 19th century until 'modern dentistyry discovered the damage inherent. Sorry so OT it is interesting no?Bye the bye vthe majority of users were royals or the rich deserving of what they got IMHO.LOL:D
Fertlizer grade urea is often laden with foriegn materials trash etc easily removed with water solubility /filtering. which could easily make up the 2% of the fertilizers ive seen.

[Edited on 1-9-2009 by grndpndr]

Various - 3-10-2009 at 03:19

Quote: Originally posted by grndpndr  
$12.95 17# 46-0-0 . the ancients used human urine to brush thier teeth and whiten them,yum yum.Of course the ammonia used to whiten the teeth removed the hard outer
layer of dentine.
[Edited on 1-9-2009 by grndpndr]


What's your source of that information?

It is believed that in Pompeii they collected urine to use part of it as a bleach, I guess the ammonia.

Mr. Wizard - 3-10-2009 at 04:28

I don't have a source either but it's common knowledge it was used to brush teeth and bleach hair. A quick Google found many references. I even read once where it can be used to wash cobra venom from your eyes. and to keep entrails moist in the event of an evisceration. It's not always sterile, but it is approximately normal saline and probably cleaner than any other liquid quickly at hand. It can even put out a campfire.

In times of war in the black powder era, it was zealously collected to make niter.

hissingnoise - 3-10-2009 at 06:00

Quote: Originally posted by Mr. Wizard  
and to keep entrails moist in the event of an evisceration.

There goes my day. . .

Formatik - 8-1-2010 at 15:48

I was reading in Beilstein and came upon N,N-dichloro-urea, which has solubility of 4g per 100g H2O at 0º (Chattaway, Am. 41, 91). So I was thinking maybe it is possible to form it from a cold conc. clear urine solution, and thereby precipitate in a similar way as oxalate and nitrate, hoping no other troublesome compounds would form.

The compound is covered in Chem. News. 1908, 166, Chattaway (just go read it), and it certainly has its dangers but according to the latter it seems it can be handled at least for a short time and at lower temps and with the right precautions without too much risk. Dichlorourea is also a simple way to near quantitative hydrazine sulfate (Chattaway).

But I don't know how one would be able to reduce the N-substituted compound safely into the urea form without too much exertion. So I'm open to ideas on how to get to urea itself.

hissingnoise - 8-1-2010 at 16:19

Can you buy fertiliser-grade urea in your area - if you can, it usually works out dirt cheap.


DJF90 - 8-1-2010 at 17:47

Formatik: Do you have that paper as an electronic file? I cant find it online...

Formatik - 8-1-2010 at 18:33

Here you go. It's attached below.

I know urea can be bought very cheaply, it gets harder to find nowadays. But I'm also interested in the chemistry.

Attachment: Chem. News, 1908, 166 Chattaway.pdf (107kB)
This file has been downloaded 1170 times


chemoleo - 8-1-2010 at 18:45

Very interesting - although dichloro urea is precipitated from a saturated (about 8 M!!!) solution of urea through which chlorine gas is fed.
There's no telling how well this would work in the presence of all the other things contained in urine....

Far more exciting I thought is the almost quantitative production of hydrazine from it - anyone who's ever boiled NaOCl with urea knows the terrible yields of hydrazine that are obtained - and here's a route that requires urea, chlorine gas, ammonia, and sulfuric acid only! Perhaps that warrants a post in the hydrazine thread!

[Edited on 9-1-2010 by chemoleo]

Formatik - 8-1-2010 at 19:02

At least monochlorourea has come up in the hydrazine thread. It was discussed on pg. 5 of that thread. Garage chemist on the following page also described his results with the method.

The question is indeed how extractable or even safe it would be to attempt to form the compound by the urine route. It is another precipitateable urea form.

From Wikipedia, concerning poison gas use of chlorine, using a damp rag with urine instead of water to protect the nose: "as it was known at the time that chlorine reacted readily with urea (present in urine) to form dichlorourea."

Any ammonia present in urine can react with Cl2 to form NCl3, this could be risky depending on its quantity presence. Any sign of dense yellow droplets resembling in appearance olive oil are indicative of NCl3 in any probe trials, it's also not untypical to see pale yellow murkyness when it forms chemically.

[Edited on 10-1-2010 by Formatik]

Formatik - 9-1-2010 at 19:32

Quote: Originally posted by Formatik  
(Chattaway, Am. 41, 91).


Reference from Beil. is Soc. 95, 466, the former was for chloroform.

Taoiseach - 11-1-2010 at 06:48

Paten DE164755 (Schestakow , Hydrazine by Urea Hypochlorite) describes hydrazine synthesis starting from urine, it has been linked here:

https://www.sciencemadness.org/whisper/viewthread.php?tid=11...

It is not isolated as sulphate but as a ketazine tough.

Another route of possible interest was mentioned here (bottom of page):

http://www.sciencemadness.org/talk/viewthread.php?tid=6729

Proposed route to hydrazine: urea-> biuret (yield ?) -> hydrazodicarbonamide (yield 95%) -> hydrazine (yield "almost theoretical")

It could be as easy as heating urea to form biuret (supposedly in the presence of a suitable catalyst), then reacting a slurry of biuret first with sodium hypochlorite and then with ammonia to form hydrazodicarbonamide. The latter would then be hydrolysed by boiling with sulfuric acid to form pure hydrazine sulphate. Sounds almost too good to be true.

http://www.patentstorm.us/patents/7422727/description.html

Formatik - 11-1-2010 at 13:41

Pity not more than at best 25% diurea was obtained from ammonolysis. The Organic Synthesis procedure using NH3 and NaClO gets 18.5% yield of N2H6SO4. In that second thread above hazards of not controlling pH during chlorination are pointed out, if lightly acid NCl3 will form, with more acidity its decomposition can set in and that could end up real ugly. Chattaway's Proceedings of the Royal Society of London paper mentioned in the thread (also attached below) doesn't make an attempt to control pH and it shows up as he noted NCl3 formation and worked only with small amounts and extra strong cooling. In the paper by Grove and Grillot, attached also in that thread they used either ZnO or CaO. But I'm not clear as to how to separate precipitated dichlorourea from those, or if they are supposed to convert entierly into soluble chlorides. Beilstein says the best yield is at -5º using 6g urea in 50 mL water and 10g ZnO (Chattaway, Soc. 95, 465).

Attachment: Chattaway, Proc. R. Soc. 81, 381.pdf (464kB)
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[Edited on 11-1-2010 by Formatik]

franklyn - 14-1-2010 at 23:13

Technical grade urea is by far preferable to agricultural fertilizer varieties.
My experience described in the first paragraph of this post here _
http://www.sciencemadness.org/talk/viewthread.php?tid=7553&a...
is warned about in the following reference.
A Course in Inorganic Preparations Henderson , page 4, 5
Before proceeding with the recrystallization of a given salt, look up its solubility
in tables or plotted curves, since the mode of procedure will depend to some
extent upon the rate at which solubility increases with the temperature. If the
increase is fast, it is clear that a solution saturated at its boiling point will
deposit crystals very rapidly as it cools and that as a result the crystals will be
very small and imperfect. In such a case, it is better to saturate the solution
at a lower temperature in order to secure slower cooling.
If the solubility of
the salt increases rather slowly with the temperature, the solution should be
saturated at a higher temperature near the boiling point.

If the difficulties do not dissuade you , a thorough study of the nuances of
purification is advised. References follow and patented methods are also
attached at bottom.

Purification of Laboratory Chemicals 4 ed, Armarego & Perrin , Page 355
Urea [57-13-61] MW 60.1, m 132.7-132.9O. Crystallized twice from conductivity water
using centrifugal drainage and keeping the temperature below 60 °C. The crystals were
dried under vacuum at 55 ºC for 6h.
[Levy and Margouls , JACS 84 1345 19621 ] prepared a 9M soln in conductivity water
( keeping the temperature below 25 ºC )and, after filtering through a medium-porosity
glass sinter, added an equal volume of absolute EtOH. The mixture was set aside at
- 27 ºC for 2-3 days and filtered cold. The precipitate was washed with a small amount
of EtOH and dried in air. Crystallization from 70% EtOH between 40 ºC and -9O ºC has
also been used. Ionic impurities such as ammonium isocyanate have been removed by
treating the concentrated aqueous solution at 50 ºC with Amberlite MB-I cation- and
anion-exchange resin, and allowing to crystallize. [ Benesch, Lardy and Benesch JBC
216 663 19551 ] Also Crystallized from MeOH or EtOH, and dried under vacuum at
room temperature.

Solubility charts
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1989001...

N O T E - Urea has much greater solubility in methyl alchohol than ethanol
100 grams of Methylol dissolves 21.8 grams Urea @ 19.5 ºC
35 gms per 100 gms MeOH @ ~ 40 ºC

__________________________________________________________

The one interesting point of the reference on chlorourea
Quote :
When ammonia in excess is added to an aqueous solution of dichlorourea, hydrolysis,
accompanied by liberation of nitrogen and formation of carbonate, occurs, but in
addition diurea, CO(NH)2:(NH)2CO , is produced, and separates in considerable
quantity as a sparingly soluble crystalline powder. // affords an exceedingly simple
synthesis of hydrazine. Diurea, when heated with excess of strong sulfuric acid to
a little above 100 ºC is easily hydrolysed, carbon dioxide escapes, and hydrazine
sulphate is produced. This crystallises out perfectly pure in almost theoretical
amount on cooling and adding a little water.

I had looked into this before relating to hydrazodicarbanimide.
The shortcoming is the low yield of Chlorourea.

In the preliminary investigations Chattaway noted that the yield of Dichlorourea
( in an an unbuffered preparation ) depends on the pH and speed of the preparation
to reduce hydrolysis and side reactions with Chloramines. My guess hypochlorite
further accelerates the decomposition of the product. ( Cl2 + H2O <=> HCl + HClO )
Only 25 % yield is claimed. See page 385 in the following : Attached below
The Action of Chlorine upon Urea Whereby a Dichloro Urea is Produced
F.D.Chattaway , Journal Proceedings of the Royal Society of London. Series A
Vol 81, Number 549 / December 22, 1908 , Pages 381-388

Better yield of Dichlorourea is achieved in a two step preparation by chlorination of
Monochlorourea obtained in ~ 65 % yield from the chlorination of urea.
See here bottom pg. 4232 ( Experimental - Preparation of the Chlorourea Products )
The article Reaction of Chlorinated Urea Products with Ammonia and Ethylamine
http://www.sciencemadness.org/talk/files.php?pid=76762&a...
cites this reference for the preparation as done by Chattaway ,
( not attached , can someone get and post it ? )
Journal of the Chemical Society 1909 Vol 95 / page 235

I made a note without a reference that acetic acid is added to the water solution
before chlorination , dichlorourea then precipitates as a white crystalline product.
Perhaps white vinegar may do as solvent.

len1 details here procedures for chlorine production TCCA + HCl
http://www.sciencemadness.org/talk/viewthread.php?tid=9713
I believe that dry distillation of TCCA with NaCl or CaCl2 would be cheaper
and more expedient. Cl3(NCO)3 + 3 NaCl -> Na3(NCO)3 + 3 Cl2
Another possibility would be , Ca(ClO)2 + CaCl2 -> 2 CaO + 2 Cl2
Rosco Bodine posted a patent on this done in solution _
http://www.sciencemadness.org/talk/files.php?pid=43927&a...


It occurs to me that perhaps a slurry of 3 mols urea and 2 mols TCCA in a chlorocarbon ,
with a catalytic amount of HCl provided by some Urea Hydrochloride should result in
Cyanuric acid and dichlorourea. TCCA s solvated in chlorocarbons.
- Urea Hydrochloride
White to pale-yellow deliquescent crystals.
Freely soluble in water and alcohol; moderately soluble in Chloroform

- Tetrachloroethylene is readily available,
See perchloroethylene - CRC 05089 " Brakleen " parts cleaner at automotive stores,
here on the left ~ $ 4.00
http://www.jcwhitney.com/jcwhitney/product/images/large/G_17...
google " brakleen brake parts cleaner "
http://www.crcindustries.com/faxdocs/msds/5089.pdf

.

Attachment: Urea Crystallization US2297034.pdf (90kB)
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Attachment: UREA CrystallizationCA649225.pdf (860kB)
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Attachment: UREA CrystallizationUS3124612.pdf (324kB)
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Attachment: The Action of Chlorine upon Urea Whereby a Dichloro Urea is Produced.pdf (1004kB)
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[Edited on 15-1-2010 by franklyn]

franklyn - 17-1-2010 at 00:04

correct spelling -> Hydrazodicarbonamide

Edenite - 13-1-2011 at 03:39

I wanted to try this experiment, and have boiled down a few liters outside over an open fire (quite high temp, flames all over the kettle).
I do not advise doing this procedure inside. Not even the slightest amount (such as the thin layer of conc. urine left in the kettle after content is emptied. I wanted to dry off the rest, took only few minutes, but the stench is hardly tolerable beyond those minutes)
For various reasons, I had to stop the process before done, so I poured the content in a mason jar, sealed it, and left it outside (where I live, temp ranges from -2C to -12C this time a year)

You can also extract phosphor from the urine, and the yields are supposedly higher when the urine is left to ferment a while.
Now ideally, I would like to gather both urea, and phosphor from the conc. urine, but as urea breaks down to ammonia over the course of a few days, im unsure if it is possible even when stored almost frozen.

Could the ammonia be extracted through fractional distillation? (guess the phosphor would precipitate in first container of water, whereas the ammonia in,,,?)
I've seen links referring to electrolysis of urea. Anyone has an opinon on that? Sounds like a simple method.



Sidenote: I've seen bunch of people on the net that swears to urine, and wood ash as a fertilizer, with the conviction that it is better than artificial fertilizer because its "organic". Fact is that there are too high concentrations of impurities (such as salts) in both materials, so for those who like to make fertilizer on their own (for whatever reason), this might be a way more hygenical method (maybe).

The WiZard is In - 13-1-2011 at 12:31

Quote: Originally posted by Edenite  

Sidenote: I've seen bunch of people on the net that swears to urine, and wood ash as a fertilizer, with the conviction that it is better than artificial fertilizer because its "organic". Fact is that there are too high concentrations of impurities (such as salts) in both materials, so for those who like to make fertilizer on their own (for whatever reason), this might be a way more hygenical method (maybe).




THE URINE OF MAN.


1. The urine of man.—Human urine consists, in 1000 parts of—

Water, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 932
Urea, and other organic matters containing nitrogen . . . . . . 49
Phosphates of ammonia soda, lime, and magnesia, . . . . . . . 6
Sulphates of soda and ammonia, . . . . . . . . . . . . . . . . . . . . . 7
Sal ammoniac, and common salt, . . . . . . . . . . . . . . . . . . . . . 6

1000 lb. of urine, therefore, contain 68 lb. of dry fertilising matter of the richest quality, worth, at the present rate of sell¬ing artificial manures in this country, at least 10s. a cwt. As each full grown man voids about 1000 lb. of urine in a year, the national waste incurred in this form amounts, at the above va¬luation, to 6s. a head. And if 5 tons of farmyard manure per acre, added year by year, will keep a farm in good heart, 4 cwt. of the solid matter of urine would probably have an equal effect; or the urine alone discharged into the rivers by a popu¬lation of 10,000 inhabitants would supply manure to a farm of 1500 acres, and would yield a return of 4500 quarters of corn, or an equivalent produce of other crops. MIr. Smith of Deans¬ton considered the urine of two men to be a sufficient manuring for an acre of land, and that when mixed with ashes, it would produce a fair crop of turnips. (Report of Committee on Metropolitan Sewerage.)

An important chemical distinction exists between the urine of man and that of the cow, the horse, and the sheep. It con¬tains, as is shown in the previous page, about 6 per cent of phosphates, while these compounds are entirely absent from the urine of the other animals. The presence of the phosphoric acid contained in these phosphates, adds very much to the ma¬nuring value of human urine.

If milk or lime be mixed with fermenting human urine, this phosphoric acid is precipitated with a portion of the animal matter. Dr. Stenhouse found a precipitate of this kind, when dried at 212o. F., to contain 40 per cent of phosphoric acid and of organic matter, including about 1 per cent of ammonia. By the use of this method, an important part of the fertilising ingredients of human urine may be separated in a solid state. It has recently been adopted with some success for the purpose of separating the fertilising matters contained in sewage water.

6. Sulphated urine.— A better method than that of using gypsum has been lately adopted by several manure manufactures. They mix much sulphuric acid with the urine as is sufficient to combine with and fix the whole of the ammonia which may be produced during the decomposition of the urine. The mixture is then evaporated to dryness, and is old and applied to the land in the state of a dry powder.

This sulphated urine, containing as it does all the saline sub¬stance of the liquid urine, with the addition of sulphuric acid, ought to prove a most valuable manure. If prepared from human urine, it will promote the growth of nearly all crops ; but, from the sulphuric acid it contains, it may exercise a special influence on beans, peas, and clovers. As a top dressing it may be applied alone ; but when used for root crops, it ought to be mixed with and to take the place of not more than one half of the farmyard manure usually applied. Used in this way, at a cost of £2 an acre, Mr. Finnie of Swanston obtained, in 1843, four tons of turnips per imperial acre more than from an equal cost of guano.

As a top dressing for wheat, and probably also for other corn crops, this sulphated urine may be advantageously mixed with an equal weight of sulphate of soda or of common salt, with at least as much wood ashes, if they can be had, and with half its weight of dissolved bones. The soda salts are especially desir¬able where the land lies remote from the sea.

7. Ammoniaco magnesian phosphate. Boussingault fixes the ammonia and phosphoric acid of human urine by adding to it, after it has acquired an ammoniacal odor, a solution of sul¬phate or muriate of magnesia, when the double phosphate of magnesia and ammonia falls to the bottom of the liquid. About 7 lb. of this salt are obtained from 100 lb. of urine ; and it has been ascertained to possess powerful fertilising pro¬perties.*

* In reference to liquid manures, I strongly recommend to my readers, the " Minutes of Information collected on the Practical Application of Sewer Water, and Town Manures, to Agricultural Purposes," published by the General Board of Health

Elements of Agricultural Chemistry and Geology
James F. W. Johnston
C. M. Saxton New York 1855


----
Here we have some progress , this being the only British City
[Glasgow], as far as I know, in which the public urinals are
utilized for the production of ammonia.
ED. C. Stanford, Esq.
Inaugural Address by the Chairman,
The Society of Chemical Industry, Glasgow and West Scotland Section.
The Journal of the Society of Chemical Industry. 3 [3] 149-156. 1884.

---
Trivia — Whom do the Scott's call a gentleman?

The man who takes the cap off a bottle and throws it away.

Edenite - 15-1-2011 at 11:04

Cool, thanks for the reply!

Unfortunatly sulphuric acid is rather hard to come by where I live.

Actually, phosphor is not really a big problem. From what I have read, it can be extracted from charred bones (with higher yields, and less stench).

Can I get the ammonia from the urine through distillation, similar to how I can get phosphor?

Formatik - 15-1-2011 at 11:28

You need to hydrolyze the urea with a base (Ca(OH)2, K2CO3, etc) in solution to get any significant amount of ammonia out of it.

bbartlog - 15-1-2011 at 15:12

Fermentation will eventually release the ammonia as well, even with no acid or base added. Over time standing urine becomes basic:

(NH2)2CO + H2O -> 2NH3 + CO2

Some of this ammonia is dissolved as ammonium carbonate, but as you can see from the above there is not enough CO2 being produced to bind all the ammonia. In a week a bucket of urine left standing at RT will get to about pH 9. Not sure where it tops out. In medieval times fermented urine (lant) was used as a cleaner.
However, getting pure ammonia out of this rather dilute and messy solution would be a project. Best bet might be heat the lant to drive out ammonia and connect the vessel to another one containing a smaller quantity of ice cold water, which would absorb the ammonia as it was driven off; but I expect many other smelly and volatile substances would also make the transit, so that your concentrated ammonia would still require further purification.

Edenite - 17-1-2011 at 15:38

Wow, thats pretty cool science!

@Formatik:
I came over a site (http://www.eco-trees.org/urine-broken-down-into-hydrogen-usi... ) which revolved around the electrolysis of urine as a source of hydrogen.
Does it solidify at the anode? How would it work with KOH (or that is what I think it was the first hours, boiled dry from potash, but not boiled dry), or a strong mixture of KOH and NaOH?

@bbartlog:
I boil this near the wilderness (in snowy winter) on a porous(sp? "airy") mineralblock, shrouding it in flames. Since I have almost free firewood available, I can engulf it in flames for hours, with the only effort being to refill (from a bottle) in the kettle, and add firewood every 30-50min. The really good thing was that I/we never smelled anything, besides burning wood :).
I saw a vid (which I can't find atm), showing the phosphorous in urine loosely solidifying when distilled through water. Would the same happen to the ammonia? Far as I've read, they say the phosphorous remains relativly pure.
Would the result then be ammoniumphosphate?


BTW all, the lant has been in an airtight container (mason jar), being only one night&morning in open air.
My plan is to replace the cap with a modified cap equipped with nickel electrodes, and a exit hose to a second container. I was thinking a smaller jar with same conceptual modifications, except no electrodes, and the hose going deep enough to reach water.
The pressure from the initial container (being lant) will add force for the gases to pass the second container (which hopefully is mostly ammonia and/or phosphor), and finally through the 3rd.
It's gonna be tested outside. If the first bubbles are odorless, I might consider having this in a ventilated storage room.

Does it look like I might be getting this to work? Only thing Im somewhat uncertain of is if the heat being generated through electrolysis will be enough to get the gases through the 3 containers, or if I'll be left with 2 jars of pure water, and 1 being a nasty failure.

[edit] I havent tested PH of the solution. Its been roughly 5-6weeks in an airtight container, so chances are high of it being lant.

[Edited on 13-01-11 by Edenite]

bbartlog - 18-1-2011 at 14:40

Phosphorus is driven off at a much higher temperature than ammonia (as in, at red heat long after all the water is gone). I think you would need to view ammonia and phosphorus as separate projects.
If you've already boiled the urine for a while you may already have lost much of the ammonia, as both ammonia and ammonium carbonate will be driven off at such temperatures. If you're after ammonia I recommend a fresh batch and a setup that lets you absorb the volatiles with cold water.

Quote:
My plan is to replace the cap with a modified cap equipped with nickel electrodes


Now I'm further confused. What were you trying to do, again? Three things at once? Hydrogen? Ammonia? Phosphorus?

Formatik - 18-1-2011 at 16:04

@Edenite:
Any base will work fine, you just boil it in solution. Something with hydroxide, like NaOH or Ca(OH)2 is probably preferable to breakdown ammonium salts better. I've also reported my own results of boiling CO3(2-) or OH(-) with just aq. urea in the "primordial chemicals" thread.

not_important - 18-1-2011 at 16:55

Quote: Originally posted by Edenite  
I wanted to try this experiment, and have boiled down a few liters...

You can also extract phosphor from the urine, and the yields are supposedly higher when the urine is left to ferment a while.
Now ideally, I would like to gather both urea, and phosphor from the conc. urine, but as urea breaks down to ammonia over the course of a few days, im unsure if it is possible even when stored almost frozen.

And hot urea solution hydrolise to NH3 and CO2, although slowly if catalysts are absent.


Quote:
...
I've seen links referring to electrolysis of urea. Anyone has an opinon on that? Sounds like a simple method

....


I came over a site ( http://www.eco-trees.org/urine-broken-down-into-hydrogen-usi... ) which revolved around the electrolysis of urine as a source of hydrogen.
Does it solidify at the anode? How would it work with KOH (or that is what I think it was the first hours, boiled dry from potash, but not boiled dry), or a strong mixture of KOH and NaOH?


.


http://pubs.rsc.org/en/Content/ArticleLanding/2009/CC/b90597...

You get H2, N2, and K2CO3 out, no NH3 to speak of - and that is a primary point of the process. I assume they may add KOH as the potassium level in normal urine is too low to full combine with all the CO2 from the urea content by almost an order of magnitude.

Phosphorous will remain in the liquid as phosphates salts, if the pH goes high enough it may precipitate as Ca or Mg phosphates, or just possibly as magnesium ammonium phosphate although I think that is unlikely. Remember that urine is a fairly dilute solution, and that electrolysis is working on plain urine.

As already said, getting elemental phosphorous out involves high temperatures - orange heat or hotter - with protection from air; the phosphorous is formed by reducing the phosphates or more properly P4O10 formed by the reaction of an acid with the phosphates; the acid can beH2SO4 added to calcium phosphate to form solid CaSO4 and a solution of acid phosphates, or as SiO2 added to solid phosphates and then melted by the high temperature.

Quote:
Sidenote: I've seen bunch of people on the net that swears to urine, and wood ash as a fertilizer, with the conviction that it is better than artificial fertilizer because its "organic". Fact is that there are too high concentrations of impurities (such as salts) in both materials, so for those who like to make fertilizer on their own (for whatever reason), this might be a way more hygenical method (maybe).


The chloride and sodium levels are high enough that problems may arise in drier climates. Wet seasons along with the Ca, K, and sulfate content of wood ash flush the Cl and Na from the soil. Irrigation with low sodium content water serves the same purpose, but in some areas the content of Na and salts in general can lead to buildups that hurt soil fertility.


Edenite - 20-1-2011 at 07:26

@ ALL:

Had a individual response to all, but I pressed the wrong button, so excuse me if this response is somewhat short.

@not important: That sounds alot more complicated than I thought. What do you think of this link?
http://www.ehow.com/how_4524329_make-phosphorus.html

So if I electrolyte the urea, will the N2 solidify along with the K2CO3 without any Na?

Do you know if I can reach the sufficient boiling temp. with a mason jar in oil bath (without enflaming the oil ofc)?

@bbartlog: So it would be better to distill ammonia while refilling with fresh urine, and (as its refilled) with the conc. solution go for phosphorus?
Electrolysis was more for the sake of hydrolyzing the the urea, but it serves little purpose if I boil it I guess.

[edit] Although these methods are not completly on topic, it seems to me that much higher yields and purity are achieved, than boiling it dry?
I don't remember where I read it, but Urea with alcohol is used to make a compound in the production of plastic ("polyurethane" or similar I think)


[Edited on 13-01-11 by Edenite]

bbartlog - 20-1-2011 at 17:45

Quote:
So it would be better to distill ammonia while refilling with fresh urine


Well, with something that hasn't been boiled for hours. But as noted you need either long standing or else the addition of fairly strong base to hydrolyze the urea to ammonia. On the other hand, not_important mentions that heat will do it too... maybe just boiling for hours will do the trick after all.

piss on the paper

The WiZard is In - 21-1-2011 at 10:45

A Cabinet of Curiosities — Ferment Paper


FERMENT PAPER
UREA = Brown
Synonym Musculus’ Paper

Preparation : Ferment paper is prepared by filtering decomposing
urine through white filtering-paper, then washing the latter, and
coloring it with turmeric.

Application : Ferment paper is applied for the detection of urea,
with which it yields a brown color, due to the decomposition of the
urea induced by the ferment In the paper, ammonium carbonate
being one of the products of the decomposition and affording the
reaction with the turmeric.

--------------------------------
Alfred I. Cohn Ph. G.

Indicators and Test-Papers : Their Source, Preparation,
Application and Tests for Sensitiveness

A Résumé of the Current Facts regarding the Action and
Applications of the Indicators and Test-papers which have been
Proposed from Time to Time, and are in Present Use in Chemical
Manipulations with a Tabular Summary of the Application of
Indicators. Assigned for the Use of Chemists, Pharmacists, and
Students.

First Edition
First Thousand
John Wiley & Sons, New York. 1899

not_important - 21-1-2011 at 15:29

Quote: Originally posted by Edenite  
...
@not important: That sounds alot more complicated than I thought. What do you think of this link?
http://www.ehow.com/how_4524329_make-phosphorus.html

Do you know if I can reach the sufficient boiling temp. with a mason jar in oil bath (without enflaming the oil ofc)?


Boiling point of (white) phosphorous = 280.5 C, and you have to heat it hotter than that; too hot for an oil bath. That reference is to an old alchemical style method, yields are rather small to nil.

Quote:
So if I electrolyte the urea, will the N2 solidify along with the K2CO3 without any Na?

Nitrogen - N2, the main gas making up air. MP -210 C (63K), BP -195.79 C (77.36 K). I confess full and utter confusion as to why you think N2 would "solidify". And the term is "electrolyse" (or "electrolyze" ), "electrolyte" means a substance - stuff - containing mobile ions.

Quote:
So it would be better to distill ammonia while refilling with fresh urine, and (as its refilled) with the conc. solution go for phosphorus?


I have a late 19th/early 20th century book on industrial ammonia production. A major method was the treating of raw sewage with steam and line - Ca(OH)2 - to hydrolise the uera and displace the ammonia from that and formed by bacterial decomposition of proteins. Typically the ammonia was captured in an acid, weak H2SO4 was common, from which the ammonium salt was recovered by careful evaporation (many ammonium salts lose ammonia on boiling a solution of them).

Urine is a rather dilute source of NH3, it was most efficient to drive if off from the un-concentrated material and collected as a salt that could be isolated as a solid. Making phosphorous takes a solid dry compound of phosphorous, so you do need to evaporate the urine, you could combine these two steps by adding lime and catching the distillate in a container that had some H2SO4 or HCl in it.

Quote:

I don't remember where I read it, but Urea with alcohol is used to make a compound in the production of plastic ("polyurethane" or similar I think)



Urea-formaldehyde resins as commonly used as glues and for riged insulating foams. Made by reacting urea (or a substituted urea) with formaldehyde.

Urethanes AKA carbamates are related to urea, with one amide (H2N-) group replaced by an alcohol -OR group. The compound ethyl carbamate has the trivial name of urethane.

Polyurethane is made from the reaction of polyisocyanates with polyols (polyalcohols) Polyurea is made similarly, with a polyamine replacing the polyol. See Wikipedia for more.


Edenite - 23-1-2011 at 10:10

@bartlog:
Right? If it isnt hydrolyzed, it should remain in the solution as urea. As it hydrolyzes, it can be distilled without the salt, and over time (as the boiler is refilled) it becomes a fairly concentrated solution that ought to yield either a decent amount of ammonia, or urea.

@Wizard is in:
That sounds a a very energy effective method, no forced evaporation etc... but it also sounds quite unpleasant. "poor mans urea extraction" :P

@not important:
Right, sorry for the typo. English isn¨t my mother tongue.
There is a definite uncertainty whether or not H2SO4 is available for me to buy. I know its possible to charge an old car-battery, and gather the acid which would range around 20-36% H2SO4. Although this might be strong enough to gather ammonia, Im a little skeptical to working with acids of that strength, as I lack safety gear. My goal is to avoid using too toxic methods, though there is no denial that H2SO4 will enable a wide range of fun experiments for a budding hobby-chemist :P
Although there is a lower (much lower?) yield in using the "old method", would you consider it safer? Should I be aware of possible ignition/explosion hazards?

A far-fetched amateur guess: Is it the carbon in cinnamon/charcoal that binds with the high O-content of P4O10 that makes it possible to gather by distillation (old method, see link)?

How high conc. of ammonia do you guys think I¨ll be able to "saturate" a cold-water container? 10%? 15%? ,,,

Edenite - 24-5-2011 at 06:33

Ok, the solution got thrown away due to new adress, but something notable happened to the conc. solution over the course of few months:

1: Coloration blackened until it was virtually impossible for sunlight to get through.

2: I noticed when brightning the solution (sunlight again), that the bottom was covered with grayish precipitates.

Now Im thinking that since the solution was non-transparent, Im quite unsure what would [all] be in the precipitated stuff. Im assuming that all the urea had hydrolyzed as it blackened [don't know if there is a connection though], but being in a sealed container, I find it strange that the ammonia would escape.

There might have been some phosphorus precipitated since the alkalinity in solution was likely to be relatily high, but as mentioned, there might be too little potassium, or others to gather notable yields.

As circumstances have made it more difficult to apply heat/fire to process the urine, the precipitation observed in last attempted experiment did prompt the question if this could be done without boiling down the solution. [suggestions so far are merely untried]

I my first renewed attempt was to freeze the urine as I filled a 5l bottle. This way, no spill, no smell, all swell (note: I did swell. I intentionally avoided sealing the cap completly when freezing/defrosting. I suggest the same)
When the bottle was defrosted, voila, same results, just in a bigger vessel. Also, you could clearly see that the content in top of bottle was clearer, yellowing further down.

,,, what happened? Can it be possible to simply decant a defrosted solution, then refill&refreeze, and eventually extract a greater yield from the sediments? [Could freezing in conjunction with PH manipulation be a better alternative to heat (and odors)]?

[Edited on 13-01-11 by Edenite]

bbartlog - 25-5-2011 at 13:30

We don't even know what you're trying to do, so it's hard to answer the question of whether you could 'eventually extract a greater yield from the sediments'. Urea, at least, is not going to precipitate; nor I think ammonia; so any precipitate is likely either complex biological goo or perhaps phosphates. So are you talking phosphorus?
Anyway, while ammonia from urine seems doable enough, I think phosphorus is a pretty tall order, unless all you're after is a few milligrams to say you did it. Remember, Hennig Brandt used some 6600 liters of urine to produce phosphorus for the first time (granted his process was far from yield-maximizing).

Romix - 1-8-2015 at 09:44

Quote: Originally posted by chemoleo  
No, I am not kidding!

I have always been interested in the chemicals the body produces/excretes, and urea is one of them!
Of course, urea is mostly easily available, but not everywhere. So there are ways of obtaining it yourself, from a chemical synthesiser called your own body ;)

Urea is of course an ancient, well studied chemical, in fact it was discovered over 230 years ago, and Friedrich Woehler determined that urea could also be synthesised from inorganic chemicals, i.e. by the reaction of potassium cyanate with ammonium sulfate (1828).

The original discovery of urea was by Hilaire Marin Rouelle in 1773, who obtained it by boiling urea dry and obtaining a white residue (which later proved to be identical with Woehlers reaction products - disproving the idea that the chemistry of the living is radically different from inanimate matter)

Unfortunately, simply boiling down urine doesnt quite satisfy anyone, as it still contains certain quantities of salt, creatine, ureic acid, proteins etc.

Per day, about 1.5 - 2 litres are excreted, consisting of 95% of water. The rest (in grams per day consists of)

# 25 g urea
# 1 g uric acid (metabolic endproduct of purines from DNA)
# 1.5 g creatinine (derived from creatine phosphate, the muscle booster)
# 10 g of salts, mainly NaCl
# 3 g of phosphates, citric acid, oxalic acid,
# milligrams of proteins, and urochromen, which is the compound giving rise to the yellow colour of urine.

Now, looking at this information, what could be the best way of isolating urea from it?

How about this:

1. Collect urine for about a week, one should get about 10 litres. Needless to say, urine is STERILE to start off with. Preferably though, after each urine addition, the solution should be simply boiled to keep it sterile. Otherwise, just literally pee into a sterile pot with lid, and keep it at 4 deg C for the rest of the week. I dont think bacterial contamination should be a problem then (unless your have a medical condition, where bacteria are excreted through your urinary tracts)
2. AFter a week, boil down the urine, until a solid mass is obtained (from the above table, it should way about 300 grams. Do this outside, unless you want 10 litres of water condensing on your windows
3. That's when things become interesting. You want to get rid of salts (primarily), and phosphates. At this point there is no easy way to get rid of the creatinine, and the ureic acid. Proteins aren't much to worry about anyway, as conc. are very low.
So - I checked - urea is soluble in ethanol, at 50 g / l, @ 20 degC . Probably a lot more is soluble at higher temperatures. In water, it dissolves at >1500 g/litre, so very highly soluble. I'd try to dissolve the urine residue in an excess of cheap industrial ethanol (doesnt matter if it contains other things), which would mean, around 3 litres, if you heat the ethanol up a little (no open flames ok). All the inorganic stuff (salts etc) are barely soluble in ehtanol, so they should remain precipitated.
4. Filter off the remainder, and boil of the ethanolic solution of urea (with a small amount of creatinine potentially) down to a few hundred ml's, or even to dryness. If you distill, you can obviously recycle the ethanol, although it may prove to be a pain to recycle such large amounts, considering that ethanol is cheap anyhow.
5. Alternatively, once you boiled down the ethanolic solution of urea to a few hundred ml, you could add HCl (conc) or H2SO4, and precipitate urea as the respective salt (which is surely insoluble in ethanol). The salt can be turned back into urea with the appropriate amount of NaOH.

What do you think? Sure this is a very simple way of purifying urea, and of course if you had all the reagents, one could get extremely high purities.
At least, this way, one gets about 200 g of urea, straight from urine, with the only expense of 3 litres of industrial ethanol.


[Edited on 10-1-2010 by chemoleo]


It'll be a lot, easier to frizze this 10 littre of urine.
You'll be left with a litre of concentrate, and a lot of dirty ice.
Then evap.

[Edited on 1-8-2015 by Romix]

[Edited on 1-8-2015 by Romix]

Romix - 1-8-2015 at 13:54

You tried it? Proteins and urochromes are insoluble in ethanol? Can 2-propanol be used instead?
2,6 (20 °C);

[Edited on 1-8-2015 by Romix]

Romix - 2-8-2015 at 01:34

Urea reacts with ethanol to form urethane!
Melting point 46 to 50 °C (115 to 122 °F; 319 to 323 K)


Urea extraction

nelsonB - 4-2-2016 at 20:33

If urea oxalate have low solubility in water,
i don't see why not urea carbonate to have a low solubility too,
just lowering the quantity of water in the urine,
then put some carbone dioxide in it to make carbonic acid,
and lower the temperature until its precipitate.


[Edited on 5-2-2016 by nelsonB]

PHILOU Zrealone - 5-2-2016 at 05:20

Quote: Originally posted by nelsonB  
If urea oxalate have low solubility in water,
i don't see why not urea carbonate to have a low solubility too,
just lowering the quantity of water in the urine,
then put some carbone dioxide in it to make carbonic acid,
and lower the temperature until its precipitate.


[Edited on 5-2-2016 by nelsonB]

Hint...it has to do with the low basicity of urea and with the low acidity and volatility of H2CO3...
HNO3 and oxalic acid are sufficiently acidic to form a urea salt, both can be used for precipitation of urea...

jon albert - 9-9-2016 at 03:15

Quote: Originally posted by chemoleo  
Of course, semi-fermented urine samples aren't pleasant. That's why I suggested boiling them.
But then, is the smell of ammonia pleasant? Surely not. Except, in the former case, ammonia is produced bacterially...

Anyway - the debate is not so much about the issue whether it's sterile or not (and I agree about your mid-stream sample), but simply whether this particular case is 'science that goes too far'. InfantigoTragus
Rx drugs
And I just happened to disagree on that :) - if anything, I'd say, the making of highly toxic nerve gases is science that goes to far, at least for the amateur chemist!


That makes a good sense!

[Edited on 9-9-2016 by jon albert]

FranklinNewhart - 8-2-2017 at 10:16

Quote: Originally posted by hissingnoise  
Whew! Boiling down large volumes of malodorous liquid---great way to "piss" off the neighbours. . .
And large volumes would surely be needed.


During the Civil War the South had the ladies donate their pee to be used as nitrate for gun powder. It had to be boiled down to use it and when it was made into Gunpowder it really pissed of the neighbours to the North.