Greetings fellow nerds.
I need a source of guanidine for my series on making pyrimethamine.
This is because guanidine is actually a key part of the structure of pyrimethamine as you can see here.
At first i tried making it from urea and sulfamic acid but that didn't turn out too well.
Now other amateurs have been wildly successful so it's probably really easy and i'm just really lazy.
Nonetheless i did find another source of guanidine.
It's actually a component of hair relaxants.
People with stiff curly hair that want to straighten it out use these hair relaxant products.
It's strongly alkaline and softens the hair so it can be combed out.
Once in the desired shape it's neutralized and then holds the new shape.
Most products use sodium hydroxide as a base base but consumers have asked for alternatives so this no-lye version uses guanidine instead as the strong base.
To be sure, check on the ingredients list and somewhere one of the components should be guanidine, usually in the form of guanidine carbonate.
Now this also has plenty of other ingredients like dyes, surfactants, perfumes and other oils.
So we're going to have to run a few purification steps to get our guanidine.
Anyway, let's unbox our hair relaxant.
There is actually a lot of extra products like activators, shampoos and washes but we want just the component that has our guanidine.
And here it is, the liquid activator as it's called.
Doesn't look like much, let's see what we can get out of it.
Pour all of the liquid activator into a beaker.
The guanidine is all dissolved in solution so to precipitate it out we add six times its volume of acetone.
Since the starting volume was 50mL i'm using 300 mL of acetone.
In going with the theme of using stuff from the drug store i'm using a bottle of nail polish remover.
As we add it with stirring the guanidine carbonate precipitates out as it's insoluble in acetone.
Now i'd like to say my selection of six times the volume was some thorough scientific calculation with deep seated theoretical underpinnings.
But in reality i just selected that amount because the bottles of nail polish remover are sold in that size.
You'd be amazed, and probably mortified, at how much top level research is just eyeballed by the researchers.
Anyway, now we simply vacuum filter our guanidine carbonate.
Be sure to wash out the guanidine carbonate with some more acetone to remove as much of the additives as possible.
And that's it, guanidine carbonate.
Now a lot of the additives are in the filtrate but some precipitated out and are stuck to the guanidine carbonate.
So we're going to need to get those out aswell.
Change out the filtering flask since we're going to be collecting our guanidine in it.
Now to the guanidine carbonate on the filter, add hydrochloric acid until it dissolves.
I used about 50mL of 30% concentration although looking back this was probably far too much.
This converts the guanidine carbonate to guanidine hydrochloride which is highly soluble.
It's also known as guanidinium chloride.
The bubbles you're seeing are carbon dioxide.
Today is a very humid day in my lab so the hydrochloric acid is misting up like this.
Anyway once everything is dissolved, turn on the vacuum and filter the solution through.
Now we have our solution of guanidinium chloride.
I wanted to precipitate it back out with more acetone but it turns out it's extremely soluble even in a mixture of acetone water.
Nonetheless the acetone does help us remove more additives because some of them will congeal into some type of slime as seen here.
I'm not exactly certain which additive it is, but whatever it is, i don't want it in my guanidinium chloride.
So we filter it back out again to get our purified solution.
Now we vacuum distill the solution to get dry guanidinium chloride.
My vacuum source is the aspirator pump i showed in a previous video.
I'm using vacuum distillation because it's faster than regular distillation and it's gentler in that you can use lower temperatures.
Also guanidinium hydrochloride is notoriously hygroscopic so simple heating requires very high temperatures to render it dry.
We're going to need it as dry as possible for our synthesis of pyrimethamine.
I set my hotplate to about 130 celsius and also enclosed the boiling flask in a foil shroud to keep the heat in.
After the last drop comes over, let it run for another hour to ensure the guanidinium chloride is as dry as possible.
Then quickly transfer it to an airtight container.
And there it is, guanidinium chloride.
The total mass is 15g.
This is a ludicrously expensive source for this chemical for this amount and i should probably figure out how to make it for cheaper.
But for now I can move on to my pyrimethamine synthesis as this the last precursor.
There is nothing left to do now except make pyrimethamine or fail trying.
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