Pumukli
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Uric acid from urine
I'm curious how many SM members have tried to precipitate uric acid from well, yes, urine!?
It is around the 20th anniversary of my such experiment and I still have the original product in a small medicine vial somewhere. :-)
The process I used was simple: peed into a bigger beaker, added some fairly concentrated (household 25-30%) HCl, swirled around to mix (he-he, I told
you use a bigger beaker, I used a 1000ml one), and let the beaker sit in a cool, well ventillated space (outdoor wc).
The crystalls formed fairly quickly and settled. Then a few hours later (practically before one would top up the reaction mixture again) decant it.
Then repeat the process as many times as you wish. :-)
Well, the temperature may cause some "interference": I don't recommend doing it in the heat of the summer. No matter how carefully you decant it, it
will start to stink a bit after a few days. (I'm still puzzled what causes this because I doubt any polyamines would volatilize from such a strongly
acidic solution.)
Anyway, I think an average man can produce about 1 g uric acid daily. It is also interesting to compare the effects of consumed food on the produced
quantity! If you eat mostly plant matter, then you produce visibly less than if you eat lots of meat! (Who has gout probably knows this already.)
I admit the procedure has a bit of kinkiness involved, but after you stop the "accumulation phase" and transfer the crude uric acid crystalls (which
resemble sand) to recrystallisation it becomes just another compound which is waiting for working up. I used probably hot water for recryst, but I'm
not sure. I used some medicinal charcoal to decolorize it though, what I could not fully remove thereafter by filtration so my old sample has some
black "dots" mixed in. But I still love it, because it is that old now and makes me remember that crazy summer when I look at that not perfect work of
mine in that small vial. :-)
I would warmly recommend this experiment to anyone who is interested in organic chemistry, biology, biochemistry, etc. because it is easy, practically
not dangerous if you can handle acids, interesting and really has educational potential!
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kecskesajt
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Tip:Eat more meat to obtain more amines.
I made Tetramethylenediperoxidedicarbamide from my urine 
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PHILOU Zrealone
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Welcome to The Club...I made urea nitrate from it and HNO3.
Uric acid is not urea (carbamide)!
There are some structural relation on a molecular level (two urea units but a propane unit to link all in a bicyclic compound).
[Edited on 13-8-2015 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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unionised
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Quote: Originally posted by PHILOU Zrealone  |
Welcome to The Club...I made urea nitrate from it and HNO3.
Uric acid is not urea (carbamide)!
There are some structural relation on a molecular level (two urea units but a propane unit to link all in a bicyclic compound).
[Edited on 13-8-2015 by PHILOU Zrealone] |
I rather suspect that the structural relationship wasn't considered as relevant as the source.
I just wonder if uric acid is the only compound that would drop out of solution from acidified urine or if there are other things that would
contaminate the uric acid.
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Pumukli
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Unionised: there certainly are other things as well. The crude uric acid crystalls look like sand, i.e. they are not white but brownish.
After recrystallysation what I got is a nice, silky white powder.
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aga
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Now THIS is an experiment i can do in volume.
Edit:
Cool !
The same Pee is now in two conical flasks, one with 200ml Pee, 100ml 20% HCl, the other is about 150ml pee with around 1.5g of NaOH.
The HCl liquid is slowly going brown.
The basic one already has a cloudy white precipitate, and is frothier.
For those acronym obsessed, Pee isn't Petroleum Ether Extract, it's pee, wee, urine, wazz, widdle whatever you call it.
Further Edit :
The HCl mix smells oddly familiar, yet not like wee, stale or otheriwse.
The NaOH one smells distinctly of ammonia.
[Edited on 15-8-2015 by aga]
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Pumukli
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That's it, man! :-)
Yes, now I remember that the acidic mixture gets darker with time, gets brownish orange color.
Although 100 ml fairly concentrated HCl is overkill to 200 ml wee, maybe 10-20 ml should be enough. By now you should be able to see the formed
crystals on the bottom of the flask.
And yes, it has a "familiar smell", with time this smell gets stronger unfortunately. :-)
The urea in the NaOH mixed sample slowly gets hydrolized so ammonia stench is not surprising.
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aga
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The HCl one is already going a dark brown colour.
Maybe the HCl overdose is speeding it up.
No crystals though.
The 'familiar smell' is unlike wee or anything else i've smelt.
It's a bit like the first time i smelt chloroform - i kind of have a vague clue what it is, but cannot pinpoint it.
Then again, i have done hardly any OC and do not regularly sniff pee.
[Edited on 15-8-2015 by aga]
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aga
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This is about after an hour.
Pee + HCl to the Left, Piddle & NaOH to the right.
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aga
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11 hours later and no precipitate in the HCl version.
More raw material has made itself available, so will try again.
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Pumukli
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Sometimes I hardly got any crystals from a "batch", sometimes I got plenty.
I think it depends on (at least) your diet, had you made physical exercise in the previus few hours or not, sweating a lot or not, drinking too much
hence diluting it, etc, etc.
Keep trying! :-) If you fail I might try it again just to show you (and others) how to do it. :-)
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aga
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No precipitate on attempt #2.
No precipitate at all, just a darker brown/orange colour and the rancid reek of stale urine.
I tend to eat mostly vegetarian, so perhaps i'm pissing in the wind.
[Edited on 16-8-2015 by aga]
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Pumukli
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Your failure refuelled my interest in this experiment.
Yesterday I tried it: 120 ml wee, 15ml battery acid (37% sulfuric acid) into an Erlenmeyer (not the best choice, too small mouth opening), room
temperature, darkness.
After an hour or so: the color was almost exactly as yours (orange brownish). But there were no crystals! So my original remark about quick
crystallization is not true (or maybe true only if there already are some crystal seeds in the Nth refill.)
But after 12hours: bingo! There is some "sand" visible, I'd guess 50 - 100 mg, maybe less.
I ate meat yesterday for breakfast and lunch too.
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aga
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Hmm.
So you used Sulphuric acid and it worked.
I used HCl for some reason and it did not.
| Quote: Originally posted by Pumukli | | The process I used was simple: peed into a bigger beaker, added some fairly concentrated (household 25-30%) HCl |
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aga
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Just tried this again with conc SULPHURIC ACID (ahem) and the reaction appears to be much faster than was observed with HCl.
Stirring also increases the reaction rate, as seen by the rate of evolution of bubbles.
It appears to be exothermic as the temperature rises when stirred vigorously (never had my stirrer on full whack before !).
After less than 10 minutes there are small white grains appearing, although the number of grains is less than 10, so the reaction mix will be left
overnight as suggested.
[Edited on 19-8-2015 by aga]
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Pumukli
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I'm fairly sure I used HCl in those days simply because 1, I did not have sulphuric acid and 2, I hated sulphuric acid because it ruined too much of
my clothes (those familiar tiny holes) when I had tinkered with it in the past.
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aga
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Nope.
The attempt with H2SO4 hasn't worked either (yet).
The few grains i saw were probably bits of ring-pulls, kebab wrappers or something.
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Boffis
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@ Pumulki, check out the uric acid from bird shit thread. I can get about 17% uric acid from this stuff, much better source!
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Steph
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Can someone explain the actual process? Or give me a link to an explanation? I am interested in basics. How does the reaction take place? I am just
starting organic chemistry and aromathic hc are very unfamiliar to me. If I am talking s*it, let me know. Please explain like I'm 5, it would be very
helpful. 
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Pumukli
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The actual process is something like this:
You are a living "thing" and in your cells lots of parallel biochemical reactions are taking place. One of them is centered around purin based
compounds. These purin compounds are synthesized and absorbed from the food you eat. Surplus purin compounds (adenine and guanine) are oxidized to
various compounds, uric acid being their final stage in humans (and in several other animal species) before excretion from your body.
Uric acid dissolves fairly well in a high pH environment, dissolves a bit around pH 7 and dissolves very poorly under pH 7 or so. Your wee contains
the dissolved uric acid (and lots of other things). Wee is around pH 7 or slightly less. When you acidify the wee with strong acids (HCl,
H2SO4, etc) the solubility of uric acid becomes very low in that acidic environment and starts to form crystalls and drops out
from solution.
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aga
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Oh.
So you have to be Human for this to work ?
You should have mentioned that earlier.
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Pumukli
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It doesn't hurt, but e.g. dogs would be in trouble because in their body the final stage of oxydation of purin compounds is kynurenic acid. At least
this is I was told.
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aga
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Didn't work for me in 3 attempts, so i'll call it quits, because :-
#1 i don't have an immediate need for any uric acid.
#2 it stinks like an alcoholic tramps' gusset at 20 paces.
The fermenting urine from about 6 'deposits' (with no added acid) after about 3 days surprisingly smelt quite different : sweeter somehow, and very
unlike the acid-treated urine.
No Precipitate seen in either case.
"If you're not part of the Solution, you're part of the Precipitate."
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