Urine's produced by the kidneys and it's a way for the body to get rid of excess water and
water-soluble waste. The exact composition of urine varies from person to person,
but in general, this is what it contains
Not counting water, the largest component is urea,
which mostly comes from the metabolism of food proteins
However, some of it's also generated naturally as the body degrades and recycles its own proteins
For this video, I've decided to continue this month's apparent theme of urine chemistry, and I'll be isolating some urea from my own pee
Then in some future videos,
I'll be using the urea to make an old now banned artificial sweetener as well as an anti-seizure medication
Using something that was once part of me to make new chemicals is
honestly kind of weird, but I also think it's pretty cool
I should make it clear though that unless you're living in some sort of post-apocalyptic world,
this is probably the worst way to get urea.
It's way easier and cheaper to just buy it or to get it from some instant cold packs
I'm just doing it to explore the science and despite it being honestly pretty gross, I think it might be fun.
Anyway to get the project going I had to start saving all my pee in a container which was not super enjoyable.
It took about three days to collect a little over three liters of the nice golden liquid.
Most of it's just water though, which I'll need to get rid of before trying to isolate the urea.
Unfortunately the best way to do this is by evaporation, which is really stinky.
Because I didn't really want my house to permanently smell like pee, this step had to be done outside.
I picked up a large pot from Walmart, added all the pee, and then heated it up on a small electric burner.
I also set up a fan off-camera to continually blow on it and speed things up.
As the pee is heated, proteins and minerals will start to fall out of solution,
causing it to become opaque. The urea is extremely water-soluble though and will remain dissolved.
The goal here is to get rid of almost all the water until I get to a volume around
150 to 200 millilitres.
Surprisingly, at the beginning it really wasn't that smelly but it slowly got worse and worse.
By the time that it was done, it absolutely reeked and was very unpleasant.
While holding my breath, I quickly took it off the burner and poured it all into a beaker.
I then covered it with some plastic wrap and brought it inside to cool.
This wasn't the greatest idea though because even with the plastic, the smell was easily able to pass through.
It didn't stink up the whole room, but it was definitely a little gross in the area around my workbench.
When it eventually cooled to room temperature, I vacuum-filtered off the solid stuff.
As I mentioned before,
this is a mixture of proteins, minerals, and other pee components.
I waited for everything to pass through and then I washed the beaker and the filter with a little bit of water.
In the flask below, I have all the liquid that passed through the filter,
which is extremely dark and nearly black.
This extremely concentrated pee contains all the urea, and to get it out
I'm gonna have to chemically process it.
To do this, I transfer it all to a beaker and start adding concentrated nitric acid.
This reaction produces a lot of heat and it can easily get out of control,
so the acid has to be added slowly, with a lot of mixing in between.
The nitric acid quickly reacts with any urea that's present to produce urea nitrate,
which is not very soluble in water.
The pure form of urea nitrate is white, but unfortunately as it precipitates it picks up a lot of colored impurities
so it ends up being a dirty brown color instead.
It also puffs up a little and makes some nice and appetizing pee foam.
This is probably the major thing to look out for with this reaction,
because if it ends up overflowing, it's not going to be very fun.
Besides the foaming, the reaction was relatively tame
but it did warm up quite a bit. So to precipitate as much urea nitrate as possible it needs to be cooled.
I continue mixing it for a few minutes, then cover it with some plastic and put it in the fridge for a couple hours.
At this point it still really stinks though,
so I tried triple bagging it to save my fridge. The smell still leaked out a little, but it wasn't too horrible.
A few hours later, I took it out and the whole mixture had solidified.
What I need to do next is filter it, so I quickly break it up using a glass rod.
Then all of the gross brown goo is added to a vacuum filter.
I turn on my pump, and most of the dark concentrated pee is pulled out.
It's all collected in the flask below, and thankfully it can now be discarded.
This is where all the stink is coming from, so from this point on things are gonna be a lot more pleasant.
I left the pump on for several minutes just to dry it up as much as possible, and then I transferred it to a beaker.
Although the urea nitrate doesn't stink that much anymore,
it's still super brown and gross so I'm gonna clean it up a little.
The easiest way to do this is to recrystallize it from hot dilute nitric acid. So I turn on the heat
and I just keep adding the acid until everything dissolves.
Then I take it off the hot plate and remove the stir bar.
As the solution cools to room temperature, the solubility of the urea nitrate will decrease and it'll start to crystallize out.
To fully crystallize everything, I again put it in the fridge for a few hours
then I take it out, break it into smaller pieces, and filter it off.
The crystals here still aren't perfectly white, but it's definitely a lot better than before.
When everything's been pulled through, I wash the beaker and the crystals a couple times with some ice-cold dilute nitric acid
then I leave the pump on for several minutes to dry things up as much as possible.
What's really nice is that from this point on,
the prep is much more pleasant because the urea nitrate I have here is practically odorless.
Anyway now that I've separated and purified the urea nitrate from the gross urine,
I need to change it back into urea.
To do this, I dump it all into a beaker, and I suspend it in a small amount of water
Then I slowly start adding a concentrated solution of potassium carbonate.
It reacts with the urea nitrate to regenerate urea,
but it also forms potassium nitrate and carbon dioxide gas as side products.
So immediately, a whole bunch of bubbling occurs,
and I realise that doing this in such a small container is a horrible idea.
To prevent a disaster, I quickly transfer it to a larger one and continue the addition.
The goal here is to just keep adding the potassium carbonate until all of the solid urea nitrate disappears.
The urea that forms quickly dissolves, and I'm eventually left with a nice and clear solution.
It's still really discolored though, so I tried seeing if activated charcoal would help.
It usually works pretty well so I mixed in a small amount.
Then to get rid of the charcoal I filtered it through some cotton and celite.
Unfortunately it turned out to be a total waste of time though,
because there was no noticeable color difference.
In any case, I now need to evaporate all of the water.
So I quickly set up a hot water bath and a fan like before.
It's really important to not heat it up too much here and definitely not to boiling,
otherwise some urea might start to degrade.
The process took a few hours, and I was eventually left with a thick syrup.
As soon as it was taken out of the water bath, it quickly started to solidify.
I let it sit there for another 20 or 30 minutes, and it became a solid chunk.
What I have here is a mixture of potassium nitrate and urea, which I'll have to separate.
To do this, I'll exploit their differences in solubilities,
where urea is very soluble in hot ethanol, but potassium nitrate is practically insoluble.
So, by adding boiling hot ethanol
I should be able to pull out the urea, but leave the potassium nitrate behind.
I add a small amount and mix it around to break up all the large chunks.
It looked pretty good after a few minutes,
and I was gonna go ahead and filter it. However at the last second, I decided to add more ethanol.
I added a random amount that I felt was appropriate,
mixed it around for about 30 seconds and then filtered it.
By the time I was done, a lot of solid had formed which I initially assumed was urea.
I figured that because the ethanol was cooling down,
the solubility of urea decreased and some of it fell out of solution.
The next step is to heat things up and evaporate off the ethanol, and if this is urea, it should redissolve.
However, even when it got to the boiling point, it was still really cloudy so this is probably potassium nitrate.
I get rid of it by just quickly filtering it through some cotton and the difference is pretty significant.
Anyway, I continue evaporating off the ethanol and when it gets to a hundred milliliters,
I transfer it to a smaller beaker.
Then, I evaporate further another 20 mils or so so the total volume is around 80 milliliters.
At this point, I take it off the heating remove the stir bar and wait for it to cool.
The crystals that form first are very needle-like,
and I think it's actually potassium nitrate.
As it cools more though, we start to see some lighter and fluffier crystals, which I think is the urea.
When it eventually got to room temperature, I put it in the freezer and cooled it overnight.
Then just like we've seen before I break everything up and filter it off.
After everything is pulled through,
I wash it a couple times with some ice-cold ethanol to try to get rid of the color.
It seemed to get rid of some of it, but it was still quite yellow which I didn't really like.
This yellow color is mostly due to a pigment called urochrome,
which comes from the breakdown of haemoglobin.
It's generated pretty consistently by the body, and it's the reason why pee is yellow.
Anyway, to get rid of the urochrome and any potassium nitrate that still might remain,
I just need to recrystallize it a few more times from a mixture of water and ethanol.
On the last run nothing crystallized even when I put it in the freezer which kind of scared me.
This does happen sometimes though,
and crystallization just needs to be induced by scraping the wall a little.
To finalize the crystallization, I put it back in the freezer for a couple hours.
Then as usual I broke it up into pieces and filtered it off.
I turned on the vacuum pump, and I was really happy to see that most of the yellow color quickly disappeared.
Then I did a couple washings with some ice-cold ethanol.
The final crystals are still slightly yellow, but it's definitely way better than before.
I let it dry overnight and the final mass was about 7.8 grams.
I have no idea how much urea I actually had in my pee, but I imagined
this is a really low recovery.
From my research, it seems like there should be at least 9 g/L
so minimally I should have gotten around 27 grams.
It is possible that I have some sort of condition or disease that makes me make really low amounts of urea
But I choose to believe that it's because of all the recrystallizations.
Some product is lost with each or crystallization,
so it's kind of a trade-off between recovery and purity.
In my case I'm using it for synthesis, so it has to be reasonably pure, and I didn't really have a choice here.
If you recall from earlier, I filtered off some pee protein and minerals, and I decided to keep them.
I let them sit out for a few days to dry and this is what I was left with.
I have no idea what I can actually use it for though,
so if you guys have any ideas I'd love to hear them in the comments.
Anyway, one final thing that I did was test the purity of the urea.
To do this I measured its melting point and I got a range of 120 - 135 °C
This is kind of close to the melting point of pure urea,
but the range is much wider, which tells me that mine is still quite contaminated.
This is fine for my future videos though and the reason I know this is because I've already filmed them.
Both of them should be posted later this month, and if you're interested in seeing them
you should definitely subscribe and turn on notifications
Some of you might have noticed that a lot of the glassware that I use is
branded with my channel name NileRed.
All of this branded glassware can actually be purchased from my website
which has the cool URL of just www.nile.red
Personally my favorite things that I sell are my beaker mugs and my beaker shot glasses.
If you're at all interested in picking this up for yourself, or as a gift you should definitely check out my website,
and I'll put a link in the description
In the spirit of the holiday season though I've decided to give away
five sets of a beaker mug and two little shot glasses.
If you want to participate, the link for it will also be in the description.
To enter it's completely free and I'll also cover the shipping for all the winners.
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