Greetings fellow nerds.
We're in the final stretch of our project to make sodium by the alcohol catalyzed magnesium reduction process.
If you haven't been keeping up with my channel for the past couple of months then you might be a bit lost but that's okay.
Briefly i've been trying to make sodium by reacting magnesium metal and sodium hydroxide, in mineral oil with a tertiary alcohol catalyst.
There have been lots of issues that i've documented in past lab note videos including trying to find a workable solvent,
reaction times, processing methods in dioxane, preventing glassware destruction
and trying to dry the reagents using easy to obtain drying agents like aluminum and lithium metal.
Recently i've been trying to find alternatives for the most critical part of the process, the tertiary alcohol catalyst.
The existing catalysts that were made earlier this year are excellent and work exceedingly well.
But take a lot of work to make so an easy off-the-shelf catalyst would be preferable even if lesser but still reasonable performance can be obtained.
After some tests without catalysts, and using some longer chain primary alcohols.
It was concluded that tertiary alcohols were necessary.
The most promising domestically available tertiary alcohol was tea tree oil.
Although it gives low yield and the sodium produced comes out in tiny spheres which reduces yield even further as some of it passes through the sieve.
Now i ordered a liter of tea tree oil online so i can try and purify it but while i wait for delivery i wanted to run a few more experiments to make best use of my time.
First i wanted to do a practice run using lithium as the starter and do everything at once in one pot.
But it turned out that 40g of sodium hydroxide and 30g of magnesium was simply too much to stir.
The reason why i was able to use so much reagents in prior videos was because i did the drying step separately
and that actually ground down the sodium hydroxide into a powder so i could subsequently add magnesium without clogging the system.
So if want to do everything at once i should use smaller amounts.
So i setup a new run this time at half scale using just 20g of sodium hydroxide with 15g of magnesium and a single lithium battery as the starter.
I also wanted to test out unpurified tea tree oil some more since a single experiment doesn't necessarily prove tea tree oil is unworkable.
So i started heating and went through the drying process where we heat to 125 celsius for a few hours
and then we went to the sodium production temperature at 200 celsius andů ohhh crap.
*sigh* Well f*** you too.
So after i cleared the fly out i started all over again.
20g of sodium hydroxide, 15g of magnesium metal, 150mL of mineral oil and 1.2mL of straight tea tree oil.
This time i stuffed some paper towel in the bubbler to keep out suicidal flies.
They'll need to find some other amateur chemist to end their existence.
As usual i heated up to 125 celsius and held for a few hours to dry out the sodium hydroxide and protect the glassware.
Then i raised up to operating temperature at 200 celsius and held for 36 hours to produce sodium metal.
Pouring through the sieve this time it still has the coalescence problem as in my previous video and produced small sodium spheres.
So it's not a one time error, tea tree oil might have sodium coalescence problems.
Anyway, i poured the sodium back in the flask and performed the dioxane separation process to try and get a sodium yield.
Recovering the sodium this is all we got.
I measured the mass to be about 4g out of an expected 11.5g for about 34% .
So tea tree oil does work, just not very well.
34% is just barely acceptable though being somewhat worse than our 40% for the thermochemical dioxane process.
Now i suspect we lost most of our yield through the sieve during the original filtration if the sodium was too small to collect.
So i poured some of the slurry into water to see if there was sodium level reactivity.
And it looks like there is.
So we might have indeed higher yield.
But something about tea tree oil makes it hard for the sodium to coalesce together.
Now i know what you're thinking.
What about the lithium jumpstart.
This is the first time i'm using lithium in a full production run so maybe it's causing the bad sodium coalescence.
This is not a bad idea, we did see lithium interfering with sodium coalescence in earlier experiments so maybe it's the lithium.
So i ran a new experiment this time with a sodium jumpstart.
3.5g of sodium metal in addition to our current set of 20g sodium hydroxide, 15g magnesium, 150ml mineral oil and 1.2mL tea tree oil.
Once again we go through the start up procedure of drying at 125 celsius for a few hours before ramping to 200 and letting it run.
Interestingly this time we got backflow at just 11 hours indicating the reaction had stopped.
I'm not sure if this is a good sign.
Pouring off the slurry this time the sodium coalescence is much better.
Most of the sodium stuck together as desired and remained in the flask.
So maybe the lithium is really is the problem.
I then ran the dioxane separation process as usual and obtained sodium.
Weighing it this time we get about 7.6g.
But keep in mind we started with 3.5g of sodium in the jumpstart reaction.
So our actual yield is about 4.1g.
We haven't done much better than earlier with lithium.
So overall this tea tree oil just isn't doing well.
I definitely think the next step is refining it somehow.
Unfortunately i can't do that until my shipment arrives.
So i'm going to do another unrelated experiment i've been meaning to do but haven't had the time for, a substoichiometric run.
So far almost all of my experiments have been using a stoichiometric excess of magnesium to sodium hydroxide.
I did this primarily for consistency purposes to overcome depleting factors like excess water in the sodium hydroxide, oxygen in the air destroying our yield,
the fact that alcohol also depletes a small quantity of reductant and so on.
But having an excess of magnesium means we always needed a dioxane separation step.
It would be awesome if we could avoid that and just have pure sodium produced directly.
Magnesium is also the more expensive reagent compared to sodium hydroxide.
Saving it would be more cost effective.
So i setup a new run consisting of 20g of sodium hydroxide and just 10g of magnesium metal which is lower than the stoichiometric equivalent of 12.15g.
I also had 3.5g of sodium metal jumpstart and the usual tertiary alcohol of 3-ethyl-3-pentanol along with 150mL of mineral oil.
I'm not using tea tree oil for our catalyst in this experiment as i want to keep this run comparable to our other high yielding runs.
Interestingly enough something very strange happened, the reaction never stopped.
It kept producing hydrogen but got slower and slower and slower.
Eventually it would take ten minutes between hydrogen bubbles but never stopped and back flowed like all my other runs.
After 3 days i refused to spend more time and stopped the reaction.
I processed it like usual pouring off the slurry and boiling with dioxane to purify the sodium.
So far it looks good, this is a respectable sodium yield.
Now keep in mind we had a 3.5g sodium jumpstart so our actual yield is 9.2g.
Our expected yield is 9.45 so we're doing pretty good at 97% yield based on magnesium limiting reagent.
This is consistent with our other runs that also had high yield.
Checking in the dioxane was can see there is leftover magnesium.
Unfortunately this is not what we wanted.
If this worked and all the magnesium was used up then there shouldn't be any leftover magnesium.
The point of this experiment was to use up all the magnesium so we wouldn't need a dioxane separation step.
But it seems this will never be the case.
What i think is happening is that as the quantity of the magnesium gets smaller and smaller the rate of reaction gets smaller and smaller as well.
This makes sense because the magnesium surface area is reduced.
But as such it'll take an extremely long time to consume every last bit of magnesium.
It also took us 3 days to get this far.
Rather than saving time we ended up taking more time.
But i suppose if you can accept magnesium contamination then this isn't that bad.
You can avoid the dioxane separation step and use your sodium for more forgiving purposes like storing and drying solvents
or performing robust reactions that don't require high purity sodium.
For my future experiments I'm going to continue using an excess of magnesium so things finish faster.
But at least we learned that using a substoichiometric amount is acceptable if you accept either lower yields, or longer reaction times.
Now you might wondering, if a substoichiometric amount of magnesium ran very slowly, would a super stoichiometric excess run super fast?
Since i had nothing better to do with my time while i waited for me tea tree oil shipment i indeed ran that experiment.
This time i used an equal amount of magnesium to sodium hydroxide at 20g each, much higher than all previous runs.
Unfortunately it still took about two days which is consistent with my other runs.
This is likely because alcohol concentration and other factors also put limits on the rate so there is no one variable we can improve to substantially increase it.
Oh well. At least we know that throwing more magnesium at it would be a waste.
Okay, that's it for lab notes for now.
Hopefully my tea tree oil will arrive soon and we can go through the process of purification to get something better.
Now moving on.
I'd like to announce a giveaway of some molecular model kits.
For those of you that don't know, molecular model kits are used by chemistry professors to extort money from chemistry students.
They also have a lesser known use to build molecules for demonstrating molecular structures.
Now i know you're going to say there are hundreds of model kits out there and they're really easy to buy online.
Heck if you were really stingy you could make your own models from gumdrops and toothpicks.
What's so special about these kits that i'm giving away.
These particular ones have magnets inside so they stick together.
It's always fun to play with magnets.
And the magnets have been strategically placed so they enforce the geometry.
Let me demonstrate by making ethane.
And there we go, that's ethane, and as you can see, we have sp3 hybridized carbons with their associated tetrahedral geometry.
We even have free rotation about the carbons.
Interestingly the surfaces have been further engineered to enforce geometry of double bonds.
Let me do a basic dehydrogenation reaction of removing these hydrogens.
Now if we reconnect the carbons we have ethylene with the correct planar geometry.
But more importantly the texture on the surface of the carbons makes this hard to rotate.
You'll actually break the bond if you try.
This matches with the actual molecule that doesn't allow rotation for sp2 hybridized carbons like this.
Now granted, most well-designed model kits enforce geometry.
But i like this one since it's more fun and intuitive to do it with magnets than just plastic sticks for bonds.
And for other model kits, you have to use different carbon atoms for sp3, sp2 and sp hybridizations.
Here the same carbon atom has functionality to do it all like you find in nature.
Now i know some of you are going to accuse me of being paid for this plug.
But unlike all the other times i've been a greedy money grabbing bastard, this time i'm not.
I am getting no compensation whatsoever for this.
I just happen to know the makers of these kits and i was able to procure a bunch at a discount.
I got about twenty kits and i'll be giving out half to my top patreon contributors, a quarter to random contributors, and a quarter to random youtube subscribers.
The only thing you have to do to participate in this giveaway is to be a patron or be a subscriber and comment on this video.
You have more chances if your are patron though due to smaller sample size.
I'll announce the lucky winners in my next vlog.
If you like these kits and want to buy your own directly you can visit the website of the creators at realatoms.com, I've also included link in the video description.