Thứ Sáu, 30 tháng 11, 2018

Waching daily Dec 1 2018

My name is Miranda Wang

and I am one of the 2018 Young Champions of the Earth

representing North America.

With me today is Mr Erik Solheim who is an executive director

of UN Environment.

And also here we have Miss Dia Mirza.

You're the crush of everybody in India!

So it's really my honour to be here.

What got you excited about the environment

and become an environmentalist?

My mother never used plastics. I can't think back to a time

when we used any kind of container for food or water

that was made of plastic.

School had a lot to do with understanding that

we were citizens of this planet.

What is the good work that is going on in the world right now?

Not Dia and myself alone - a huge amount of people,

we brought in some of the gurus, the Hindu advice men,

cricket players, the COs of the big companies of India,

all into a movement to stop the enormous use

of one-use plastic in India.

The Prime Minister of India, a very brave man, Mr Modi, saying

"We will phase out all one-use plastic from India by 2022."

[Applause]

The most complicated place on planet Earth, very soon passing

China to be the most populated nation in the world.

If it can happen in India

it can happen absolutely everywhere else.

Now more than ever before people understand how useless

single-use plastics are and how dangerous they are

to the environment.

What would you say is the role of youth in these campaigns

that led to their successes?

I think mothers play a very important part in the success

of these campaigns because I think they identify and they see

the correlation between the health of environment

and their children's health. And the moment that happens

they get up and they do what needs to be done.

The most incredible thing about children and young people

is that they are forming the solution. Like you.

You saw a big problem and you said, "Hey, one second."

"This bothers me. This is not right. I have to fix it."

"And I'm going to fix it" And I think that's the power

of the youth, and we're seeing it the world over.

The question I get most often from particularly young people

is does it matter what I do? Can I change the world?

And I always reply, "Who else?"

"Is there anyone else who will change the world for you?"

You need to be the change you want to see in this world.

That applies to business, it applies to governments,

and it applies to citizens.

Two sisters, 14 and 16 years old, they started the biggest

beach clean-up ever in Bali.

When they did it, then the beministers came, then thei.

When they did it, then the ministers came, then the

business came. But they started it.

Yeah, they're friends of mine. We have a very good community.

Respond to what makes you feel the most despair.

It doesn't matter what our vocation in life is, but we can

use what we do to make a difference.

It's when we learn to care for the environment that we

understand how important it is for us to protect it.

If you move from coal to solar energy: fantastic for the

much better for the health of the people, and creating many

more jobs. There's five times more jobs in this nation

in solar industry than there is in coal.

We've invented a chemical technology by using a catalyst.

We're the first ever to achieve being able to break down

polyethylene plastics, whether it's low-density or high-density

into a variety of valuable chemicals.

And these chemicals can be used to make all sorts of products

around us. So our vision is to take the trash

out of plastic waste,

For more infomation >> Miranda Wang and the Fight for a Healthy Planet - Duration: 3:52.

-------------------------------------------

The Big Plans WWE Has Set for Dolph Ziggler and Drew Mcintyre Split Up - Duration: 1:51.

Hi Friends Wellcome To C 4 E Wrestling News The Big Plans WWE Has Set for Dolph Ziggler

and Drew Mcintyre Split Up Drew McIntyre came up to the main roster to stand by Dolph Ziggler's

side but it was very soon made clear that WWE had big plans for Drew as well He is being

positioned as one of the top faces of the company as a menacing heel but in recent weeks

McIntyre has acted apart from Ziggler Dolph suffered a slight foot injury that kept him

off of television for one week but he came back last week on RAW and answered Seth Rollins

IC Title Open Challenge Mike Johnson noted that Drew and Dolph acted in their own stories

during PW Insider Elite audio and speculated that they might be drifted apart while noting

that we will have to wait and see WWE can change their direction on an hourly basis

after all If that is the case then Ziggler and McIntyre just won't have much to do

with each other in the upcoming weeks But as heels on such a tiny roster they are likely

to see each other again in one form or fashion unless they trade one of them to SmackDown

If the former RAW Tag Team Champions are indeed no longer a team it might have been done for

a couple very good reasons but perhaps WWE just didn't want to spoil the surprise of

Ziggler answering Seth Rollins' big challenge on RAW this week Friends what are your thought

about this Have your say in the comments section below

For more infomation >> The Big Plans WWE Has Set for Dolph Ziggler and Drew Mcintyre Split Up - Duration: 1:51.

-------------------------------------------

Lab Notes - Fundamental Mechanistic Insight and New Catalysts for Making Sodium - Nov 30th 2018 - Duration: 33:10.

Greetings fellow nerds.

As you know i've been making sodium these past several months using the alcohol catalyzed magnesium reduction approach.

We had a lot of problems and we solved every single one.

Including trying to find a workable solvent, reaction times, processing methods in dioxane, preventing glassware destruction,

trying to dry the reagents using easy to obtain drying agents like sodium and aluminum metal.

And most recently we found two off-the-shelf catalysts for the reaction including 4-terpineol which is easy to get but needs to be fractionally distilled from tea tree oil before use.

And tetrahydrolinalool which can be used directly from the bottle but is somewhat harder to find and buy.

In fact, very recently as of this video one of the very few online suppliers for it actually stopped selling it to new customers.

So it's clear that tetrahydrolinalool is not very amateur accessible.

Fortunately after an exhaustive search I found another perfume and fragrance chemical that can be used.

2,6-dimethyl-2-heptanol, also known under the trade name of dimetol.

I tested dimetol and it works just as well as tetrahydrolinalool, finishing in 20 hours and providing a similar 95% yield.

While it's not easy to find and buy, the more viable off-the-shelf alcohols we have, the more likely it is the amatuer chemist can find at least one.

So i decided at this point to put everything together and make the final synthesis video.

I washed my glassware and got out my old lab notes and started writing the scripts and experimental procedures.

Eventually i started updating the reaction mechanism to reflect the things we've learned and observed so far.

In the original mechanism i presented water was a key intermediate for some of the steps.

But now we know that even a tiny amount of water destroys glassware and we were able to stop that by eliminating water.

So the primary sodium production mechanism probably doesn't have much water in it.

I thus rewrote the mechanism this time using alcohol as the primary proton transfer reagent in addition to its original function as the metal transfer reagent.

Now the old mechanism might still be correct at high temperatures especially when there is no sodium jumpstart.

But it eventually transfers over to the new mechanism as water is completely depleted and there is available sodium to use in the new mechanism.

Anyway, I wrote in water up here for the sodium hydroxide drying step but this not part of the main reaction.

So don't worry about it, it's just there for completeness.

What happens is first sodium metal reacts with the alcohol present to make sodium alkoxide and hydrogen gas.

The sodium alkoxide then reacts with water to make alcohol again and sodium hydroxide.

Overall this dries the water out of the reaction by destroying it with sodium and using alcohol as the catalyst.

You might be wondering why i wrote it out this way and not simply have sodium react with water directly.

This direct reaction does happen but it's slower.

This is because most of the water is absorbed into the sodium hydroxide itself.

So the sodium metal has to wait for the water to diffuse back out.

The alcohol, being much less polar than water diffuses much better in non-polar solvents so this alcohol catalyzed drying reaction is much faster.

This trick of using a mobile transfer reagent is used a lot in chemistry.

Especially when dealing with mixtures of solids or heterogeneous reagents.

A transfer reagent that moves easily between two chemicals greatly speeds up the process.

Anyway, as said before, I put this here for completeness.

It's not actually important.

Once all the water is depleted it is no longer relevant or even part of the reaction.

It's these next three steps that are important.

I'm also going to write in step numbers for easy reference and to emphasize how important they are.

We start with sodium metal reacting with free alcohol to make sodium alkoxide and hydrogen gas.

Then we move on to reacting magnesium metal and sodium alkoxide to make sodium metal and magnesium alkoxide.

This is the actual sodium production step.

Finally we have the magnesium release step where the magnesium alkoxide reacts with sodium hydroxide to make magnesium oxide, alcohol and sodium alkoxide.

The cycle then repeats.

Now just because i can write down a mechanism doesn't make it true.

I can similarly write down a mechanism involving tiny little elves moving things around and that would also work.

So i'm going to try and justify as many steps as i can.

The easiest step to find evidence for is actually the second step.

Magnesium reacting with sodium alkoxide to make sodium and magnesium alkoxide.

We actually directly observed this way back in our theory testing experiment in May of this year.

In that experiment we first dissolved sodium metal in 7-hexyl-7-tridecanol to make the sodium alkoxide version of that alcohol.

Then we dropped in magnesium metal and just before we dropped in sodium hydroxide we could observe what appear to be tiny little spheres of sodium forming.

They were very tiny but they formed before we had added the sodium hydroxide.

The sodium had to have come from a reaction with the sodium alkoxide already present.

So this validates the second step.

Now validating the first step requires a bit more work.

This reaction in itself is already well known and happens everyday in labs around the world when they dry alcohols with sodium.

In fact we ourselves performed the exact same reaction in the theory testing experiment we were just talking about.

We react sodium and 7-hexyl-7-tridecanol and clearly it's producing hydrogen and making the alkoxide.

So we're certain it can happen.

But i say it's the harder step to justify because the real question is whether this step is the primary hydrogen generator in the actual alcohol catalyzed magnesium reduction reaction for making sodium.

I would argue yes.

The best alternative mechanism is for magnesium to react and form the alkoxide.

While this can happen, it happens at higher temperatures.

In fact our whole glassware destruction problem occurred because we needed higher temperatures to get the reaction going on magnesium alone without sodium jumpstarts.

Temperatures that were also high enough to damage the glassware.

But as soon as we used sodium jumpstarts we not only avoided glassware destruction, but the whole production reaction proceeded at much lower temperatures.

So i think sodium reacting with alcohol is where most of the hydrogen formation is occurring.

But i could be wrong.

Maybe it's some sort of sodium magnesium alloy that truly operates under these conditions or even a weird zero valent solvated magnesium atom.

I don't know.

But i have no reason at this point to consider alternatives since the theory testing experiment works on a similar set of steps.

Now the last step is the hardest one to justify.

Not because it can't work or is hard to perform, but just because i don't have a easy way of testing it directly in this system.

Some sort of magnesium release reaction has to happen.

But how it happens is up for debate.

There is this reaction as i've written here, but there can also be a two step reaction where we have a magnesium oxyhydroxide and alkoxide intermediate.

This reaction is actually equivalent overall to the last one.

But i don't have clear evidence for one or the other.

There might even be surface effects.

Like if this 2 step reaction occurs, maybe the magnesium oxide release step only occurs on the surface of larger magnesium oxide particles.

And this might be how the magnesium oxide particles grow in solution.

This gets into the realm of solid state chemistry, and surface chemistry, and possibly nanochemistry.

As you can see, things can get really complicated really fast even in very simple systems.

I'm going to invoke occam's razor and just go with the single step magnesium release mechanism.

But i won't challenge anyone who comes up with evidence for an alternative mechanism that fits the data.

Now to help us see the catalytic cycle better i'm going to write out our mechanism as a diagram.

Yeah it looks more complicated than NFL play breakdown analysis but it's actually quite straightforward once you know what you're looking at.

Here we have the first step in our reaction with sodium reacting with alcohol to produce sodium alkoxide and hydrogen gas.

The sodium alkoxide reacts with magnesium to create sodium metal and magnesium alkoxide.

Finally the magnesium alkoxide reacts with sodium hydroxide to produce alcohol, magnesium oxide and sodium alkoxide again.

It your wondering where water gets dried out then that's not part of the main reaction but we can draw that in a seperate reaction if desired.

I'm going to leave it out for now just to keep things simple.

At this point you're asking why I just wasted 5 minutes even describing this to you and why this is important.

When you have nice and reasonably accurate mechanism built,

you can start considering alternative chemistry and use your mechanism not as a description, but as a tool to create new reactions.

Having a stepwise mechanism and a diagram helps to better see issues and possible avenues for research.

You know, i should frame this and hang it up on my wall.

It's one of the very first amateur constructed reaction mechanisms here on youtube.

Anyway let's move forward and see if we can use our mechanism as a tool to find better and faster catalysts.

Examining the mechanism closely it looks like steric bulk on the alcohol should affect the reaction.

In chemistry, whenever we see two atoms or groups of atoms bumping against each other,

but not directly bonded or reacting, we call that a steric interaction.

If this affects the reaction somehow, like blocking reactivity, then we call that a steric effect.

That's what i think is happening here.

In case you're wondering the first step isn't an issue for any alcohol since the change in steric bulk is very little.

Sodium and hydrogen are both singly charged, and we're not really forcing together two bulky alcohols.

Each alcohol bonds to its own sodium so everyone is happy.

It's the second and third step where things get interesting.

The tertiary alcohols are very large and bulky and interact with each other near the magnesium.

Think of it like two T-Rexes fighting over a steak.

Although i'm not sure if steaks existed back in the jurassic period.

Anyway, they're so big that it's really hard for both of them to hold onto the steak at the same time.

This is analogous to our tertiary alcohols.

So steric bulk should play a role in how easy the reactions go.

In the second step, steric bulk is increasing.

Two separate alcohols must bond with a one magnesium so they're both bumping into each other.

This step should be slower if we're using very big bulky alcohols.

It won't stop though.

This is a single displacement redox reaction and redox reactions tend to have very high equilibrium constants.

But the rate should be affected.

The third step is what i call the magnesium release reaction.

The sodium hydroxide enters the catalytic cycle and reacts with magnesium alkoxide to release magnesium oxide and produce the various alcohol and alkoxide species.

In this step the steric bulk is decreasing.

We're going from two alcohols bonded to one atom, to two alcohols bonded to separate atoms.

Now i know we're still unsure if this step is correct or if it even proceeds in one step.

But we do know that overall we have to go from magnesium alkoxide to magnesium oxide.

And release to separate alcoholic species.

So overall the steric bulk around the magnesium has to go down.

So steric bulk is favorable in this reaction as the relief of steric bulk drives it forward.

This might actually explain why primary alcohols don't work, since they have no steric bulk they can't release the magnesium.

But i would need to run some specialized experiments to prove or disprove that.

Anyway, looking at the mechanism we can see that if we use less and less bulky alcohols, we should improve the speed of the second step.

And using bulkier and bulkier alcohols we should improve the speed of the third step.

So which one is more important? It looks like our direct experimentation has shown that using less bulky alcohols is more important.

Going from 3-ethyl-3-pentanol to tetrahydrolinalool improved the reaction times from around 30 to 40 hours down to 20 hours.

Now i know that we didn't need a mechanism to tell us that less bulky alcohols would be better,

but having a mechanism lets us rationalize our observations.

At this point some of you might be screaming at the screen that tetrahydrolinalool looks bigger than 3-ethyl-3-pentanol.

So why am I calling it the less bulky alcohol.

The answer is that the interesting chemistry is happening around the alcohol group.

That's where the magnesium is bonding and that's also where steric interactions with other alcohols are highest,

so the immediate environment around there is most important.

This tail on the tetrahydrolinalool is far away from the action so it doesn't really interact.

The reduction of an ethyl group to a methyl group has a far greater steric effect in this situation than extending an ethyl to a long chain.

So tetrahydrolinalool is therefore called the less bulky alcohol despite actually having more atoms than 3-ethyl-3-pentanol.

Anyway, bottom line, tetrahydrolinalool is less bulky and proceeds faster than 3-ethyl-3-pentanol.

So can we do even better and faster? Unfortunately it looks like we're at our limit.

Going from tetrahydrolinalool to dimetol didn't improve things much.

We could go even smaller to t-amyl alcohol and t-butanol

but it was hard to accurately measure the rate as one of the problems I ran into is that they're volatile and boil out as the reaction runs.

I needed a condenser to keep them back in

but this introduces a further complication in that now we have to worry about equilibrium vapor concentrations in the headspace of the flask.

Another problem with t-butanol is that it actually freezes in the condenser since it's melting point is higher than the cold water i'm using for coolant.

So accurately measuring them let alone taking advantage of their performance is difficult.

In any case, neither alcohol is directly amateur accessible.

We already knew they work, but they're not good candidates for amateur friendly high speed alcohols.

Are we at a dead end? What if we go, even less sterically bulky, what if we go with secondary alcohols?

We might use ones that are bigger in terms of mass, but the steric bulk around the alcohol group can be smaller, even smaller than t-butanol.

Unfortunately, as we've seen in our earlier experiments, secondary alcohols don't give very good yields.

Interestingly enough, if we check our mechanism, there is something very big and very important missing.

It doesn't explain exactly why secondary alcohols work badly.

According to our mechanism, if an alcohol doesn't work, it should stop completely.

It would get completely stuck on one of the steps because it binds to magnesium too strongly or not strong enough.

If it does work, then it should work completely.

It might be slow, it might take days.

But eventually it will run through and all alcohols should give us 80-90% yields at best.

Tertiary alcohols behave consistently giving high yields even if they have radically different reaction times.

Primary alcohols also behave consistently, completely failing to produce sodium.

Secondary alcohols only partially work, our mechanism doesn't account for that.

We have relatively pure samples of secondary alcohols so they should be working without interference.

Unlike our experiments with raw tea tree oil or patchouli oil.

Maybe for secondary alcohols there is some sort of side reaction.

A side reaction is a reaction that happens with your reagents but is not part of the main reaction under study.

In that case the side reaction destroys or alters your reagents and removes them from the main reaction.

But the main reaction itself is still working fine.

We already saw this with 4-terpineol being destroyed and requiring extra catalyst to be used, maybe that's happening here.

Now you're probably wondering why i'm bothering to pursue secondary alcohols.

While our mechanism doesn't explain why secondary alcohols fail as catalyst,

it does say that if we can get the catalyst to stay in the cycle, it should work completely.

We just have to fix whatever the side reaction is.

We would have a very different approach if the secondary alcohols didn't work at all originally.

Then it wouldn't matter if we fixed whatever side reaction there was because the main reaction is broken.

So i tried perusing the literature and finding every sort of reaction i could involving secondary alcohols

or similar organic reactions that could explain what was happening.

I looked at Oppenauer oxidations but i couldn't figure out what the hydrogen acceptor was.

I looked at E2 eliminations but i couldn't reconcile why tertiary alcohols didn't suffer the same fate.

I looked at alpha eliminations but couldn't quite find a similar example to our conditions

and I went on and on for several weeks, going through dozens of reactions and hunting down all the literature i could and i realized something.

I am a moron. And i actually mean it.

i'm a moron in that i don't know everything.

I'm trying to figure out what's going on but I simply don't know enough organic chemistry to do so.

Maybe the perfect mechanism that describes exactly what's happening is somewhere in the literature, but i don't know it.

I'm not that smart.

What i really should be doing is acknowledging i'm a moron and working within that constraint.

I should be looking for categories of catalyst mechanisms and trying to figure out experiments to distinguish them.

The number of actual possible mechanisms is unlimited, but the number of categories is quite limited.

So while it would help to know what the side reaction is, it's more important that i stop it.

So let's see what we can do.

There are deprotonation decay pathways.

Once you remove a hydrogen using a strong base, the resulting carboanion is very reactive.

Maybe we're doing that to the alpha hydrogen.

Unfortunately there is no simple way to stop this other than using a tertiary alcohol which defeats the purpose.

So we move on and hope that isn't it.

A catalyst loss mechanism that's not often talked about but still well-known is physical loss into the product.

We're making a heterogenous side product, magnesium oxide.

It's not hard to conceive of the catalyst getting stuck inside.

Looking back at the mechanism, in the magnesium release step what if the release is only partial.

Overtime we're making a non-stoichiometric magnesium oxy alkoxide.

But if we don't get the catalyst back out, it's lost.

What's interesting about this loss mechanism is that the alcohol isn't actually being destroyed, it's just lost.

So all we have to do is stop the loss.

Fortunately, we can do that by simply making it not fit onto the magnesium oxide lattice.

Tertiary alcohols do this by being too bulky right at the alcohol group by the alpha carbon.

We might be able to achieve the same effect further away by adding steric bulk on the beta carbon.

Our failure with norlimbanol shows that we can't be too far away with steric bulk so we'll need to be closer.

So let's put that in the idea pile for now.

Moving on, what if there is a free-radical decay mechanism.

Maybe we're making free radicals at the alpha carbon and that's leading to unwanted side reactions.

Most ways of suppressing free radicals is to add a radical scavenger.

Something that itself reacts with free radicals preferable to the target reaction.

But i'm worried that those substances would introduce unwanted reactivity.

So for now i'm not going to try and stop it.

But if nothing else works, we can come back to this and start adding in radical scavengers.

Okay next catalyst side reaction candidate is some sort of rotationally relevant reaction.

There are some reactions in organic chemistry that only work if you can rotate the two carbon atoms involved and their substituents so they align.

If you allow free rotation then the reactions happen.

If you block rotation you can stop the reaction, if you prealign the substituents you can encourage the exact reaction you want and block others.

One of the most well-known of these classes of reactions is the E2 elimination reaction.

Now i'm skeptical about E2 eliminations happening under our particular reaction conditions.

Especially since our tertiary alcohols should have also decayed.

But if there is some sort of rotationally relevant reaction then the solution to block it is to use a rigid alcohol that restricts rotation.

So let's put that in the idea pile for now.

Our next candidate is maybe some sort of metal and single molecule reaction.

For example a hydride transfer reaction.

There is unfortunately very little that can be done about this other than using tertiary alcohols or different metals.

Both of these options defeat the purpose.

So we'll just have to cross our fingers and hope for the best.

The next candidate is instead, a metal and multimolecular reaction.

An example of this is the Oppenauer oxidation where you need two organic molecules coordinated to the same metal atom to react.

While i don't think the Oppenauer oxidation is happening here exactly, maybe the two alcohols bound to the magnesium are doing something.

Blocking such a reaction is very hard but we can slow it down by again increasing steric bulk

and rigidity to make it difficult for the alcohols to align properly and do whatever weird and freaky things they are doing.

Basically we want to block any chemistry between them by making them really fat and unattractive to do so.

Now at this point, since we're repeating criteria, i think we can start looking for alcohols that fit them.

This doesn't mean there isn't more reactivity to look for.

For example there might be acidity issues that can be adjusted with different substituents.

But now that we have enough ideas we should start proving or disproving them to narrow down our search.

Maybe we'll get lucky and have already stumbled on the critical catalyst removal mechanism.

Anyway, what sort of secondary alcohols fit our criteria.

The first and easiest to get candidate is menthol.

It looks just like our original 4-terpineol but fully hydrogenated and with the alcohol group moved over one carbon.

In this position it's a secondary alcohol.

This is why it was originally rejected earlier on.

But now that we have a possible reason why it should work it's back on the table.

The isopropyl group here makes it very sterically bulky around the alcohol.

So hopefully this will reduce any physical loss mechanisms by making to very hard for the menthol to get stuck in the magnesium oxide lattice.

The ring structure severely restricts rotation.

While the molecule can still bend and flex into different conformations,

hopefully we've blocked enough that we can shutdown whatever decomposition mechanisms is dependent on them.

Alternatively, if we get total destruction, we'll know that we somehow favored that reaction and we'll be able to engineer an alternative.

So i ran the test with menthol.

20g of sodium hydroxide, 15g of magnesium metal, 150mL of mineral oil, 3g of sodium metal jumpstart and 2g of menthol.

And after about 30 hours, it worked.

I ran the usual processing with dioxane and got 13.5g of sodium metal.

As usual our 3g of sodium metal jumpstart means we really got 10.5g of sodium and our yield was 91%.

This a major improvement for this process.

Menthol is extremely ubiquitous.

While not as ubiquitous as tea tree oil, it is still nonetheless sold by so many suppliers around the world that finding it is pretty much a non-issue for the amateur.

It is directly useable and doesn't require any sort of processing like tea tree oil.

So while tetrahydrolinalool and dimetol might be better performing, menthol is the more reliably sourced catalyst.

I think menthol is going to be the main catalyst i feature in my videos.

On the theoretical side we've also been able to validate our reaction models.

Granted, we still don't know exactly what the issue is causing secondary alcohols to work badly.

But we nonetheless have a working solution to prevent it.

And this wasn't some accidental discovery, we made a theoretical prediction and tested it.

All of this work starting to assemble into an actual publishable scientific theory.

Now something interesting about menthol.

It took about 30 hours to run, it looks like we went too far and used too much steric bulk.

We can probably improve our reaction rate by dialing the steric bulk back a little.

But we have to be careful about running into one of our catalyst removal side reactions.

If it turns out the hypothesis steric bulk preventing catalyst lost into the magnesium oxide lattice is true, then reduction of stertic bulk would be a problem.

Fortunately, we got incredibly lucky and there is another off-the-self catalyst that has the features we want, endo-1,7,7-Trimethyl- bicyclo[2.2.1]heptan-2-ol, better known as borneol.

Let me explain the structure a bit.

It has a more complex 3D structure than menthol.

It has a six membered ring just like menthol and bridging over ontop is are these three carbons.

What's important is to focus on this alcohol and the fact that the substituent next to it is this methyl group.

This is much less bulky than the isopropyl group that was beside the alcohol in menthol.

So this should react faster, as magnesium atoms and sodium atoms can easily access the alcohol group.

The short range steric bulk is reduced.

Interestingly enough this bridging structure makes this whole face with the alcohol rigid and bulky enough that it can't get lost into the magnesium oxide lattice.

The long range steric bulk increased.

Borneol manages to improve long range steric bulk while decreasing short range steric bulk.

It's also extremely rigid like menthol so if rotationally relevant reactions are the issue then they should still be blocked.

Okay this all sounds good on paper but let's test it.

So i ran the reaction using borneol now.

20g of sodium hydroxide, 15g of magnesium, 150mL of mineral oil, 3g of sodium jumpstart and 1.4g of borneol.

And it worked, slowing to a crawl in just 10 hours.

It's the fastest catalyst we've ever had.

I processed the reaction in dioxane to get a yield of 13.1g, our actual yield is 10.1g or 87%.

This is impressive, menthol took 30 hours to work but with careful catalyst selection and looking for exactly the features we wanted, we were able to get that down to 10 with borneol.

Unfortunately borneol is like tetrahydrolinalool, it's not as common as we'd like for a reliable and amateur accessible reaction.

Nonetheless, for you highly resourceful amateurs, borneol would probably be the catalyst of choice unless we find a better one.

I planned in earlier videos to hydrogenate tea tree oil or lavender oil to make our catalysts.

But now that we have menthol and borneol I think it's no longer a pressing issue.

If we really want to make a high speed catalyst then our efforts are better spent making borneol by the reduction of camphor.

This is actually an easier reaction for the amateur since it doesn't use annoying to handle hydrogen gas.

Overall, it looks like we have our final catalyst, menthol.

It's directly useable without the need for any purification or processing and doesn't suffer the decomposition problems like 4-terpineol from tea tree oil.

While it doesn't seem to perform as fast as tetrahydrolinalool or borneol,

taking about 30-40 hours to work as opposed to tetrahydrolinalool's 20 hours, or borneol's 10.

I still think the wide availability makes it the better choice.

You know, when i started this project i thought the best catalysts would remain tertiary alcohols.

But it appears we might have two secondary alcohols as our top catalysts.

Menthol especially is amazing in how conveniently accessible it is.

Anyway, this video has been a tremendous two steps forward.

To summarize what i'm sure was a very information dense and extremely technical and confusing topic.

We've gathered all our observations so far and rewrote our mechanism to incorporate our new understanding.

We verified a few steps to be certain we weren't completely wrong.

We realized there was a major gap in our understanding regarding secondary alcohols.

We used our understanding to categorize what we didn't know

and make broad but testable hypotheses about what sort of criteria we needed to make secondary alcohols work.

Finally we tested a couple of off-the-shelf secondary alcohols that met our criteria and found they successfully gave high yields of sodium.

In doing so they validated our our selection criteria.

Not only that but we also made a tremendous improvement in reaction speed, cutting our best time of 20 hours down to 10.

I think this shows the importance of research, understanding what we're doing and building theories around it.

Earlier on we were just testing things empirically and spent months making slow and steady progress trying everything we could find.

But now that we have a reasonably working model we were able to peer into the inner workings of the process and even engineer our reactions to some extent.

Over the course of just one video we solved why secondary alcohols didn't work, why it was worthwhile to get them to work.

Finally suppressed what was making them fail and prove they did indeed work.

Then we went further and made them even better than our best tertiary alccohols.

This sort of research before took months of trial and error.

That's what real scientific insight gives you.

In fact i'll be honest, making and editing the video itself took longer than doing the experiments.

I think it's also important to mention that we still don't know exactly why secondary alcohols fail.

Being unable to use a problem based approach as we didn't know what the problem was,

we instead approached it from a solution based perspective and tested solutions that could fix multiple problems.

In real research you often don't know a great deal of what's going on.

But you can still apply overarching rules and conditions to leverage what you do know and still perform useful experiments that encompass them.

Anyway, at this point you might be asking where do we go from here.

On the theoretical side we still don't know exactly what the secondary alcohol catalyst removal mechanism is.

We know it might have something to do with steric bulk or structural rigidity.

The most informative experiment would be for me to test cyclohexanol as a catalyst.

It has structural rigidity, but no additional steric bulk compared to something like norlimbanol.

If it works badly, or fails, then the removal mechanism has something to do with steric bulk.

but if it succeeds with high yield, then we know the mechanism is a structural issue.

Unfortunately i can't get cyclohexanol so this experiment may remain unfinished.

But that's not a problem for us,

this information is only important on a theoretical level and only necessary if i want to publish my findings in a peer reviewed journal.

Us amateurs however are more concerned with practical improvements.

So on the practical side I'm not really sure where to go next actually.

I can keep looking for catalysts but i'll be honest, i'm not sure i can find something even more accessible than menthol.

But knowing that secondary alcohols are back on the table opens up a huge array of possible candidates.

Who knows, maybe a primary alcohol can work.

I said before the cetyl alcohol experiments nailed the coffin shut on primary alcohols.

Now i think i might be wrong.

Maybe there exists out there a special primary alcohol with particular structural features to work for this reaction.

I don't know, but that's what makes research exciting.

Another thing i could link into is alternative solvents.

Now nothing will beat mineral oil in how easy it is to get.

But there might be solvents that work much faster or have other useful properties.

Anyway, i keep saying the final video will be out soon.

And i keep pushing it back due to these annoying rashes of new discoveries.

I just want to say I'm sorry for the delays.

I thank you all for your patience.

I will get to it, hopefully i don't make some other discovery in the meantime.

Thanks for watching.

Anyway.

This video was a lot of work.

Probably my longest video yet that isn't a compilation of topics.

I really appreciate all my patrons on patreon for supporting me and donating to the cause.

I probably never would have gotten this far and made this sort of breakthrough without you.

Hopefully i can keep them coming.

And if you aren't a patron right now, i hope this video shows a little more of what we can do together.

So please consider donating.

For more infomation >> Lab Notes - Fundamental Mechanistic Insight and New Catalysts for Making Sodium - Nov 30th 2018 - Duration: 33:10.

-------------------------------------------

WATCH LIVE: The National for November 30, 2018 — Alaska Earthquake, 'New NAFTA' Signed, Pop Panel - Duration: 1:04:43.

For more infomation >> WATCH LIVE: The National for November 30, 2018 — Alaska Earthquake, 'New NAFTA' Signed, Pop Panel - Duration: 1:04:43.

-------------------------------------------

Meghan kicks up a stink: Bride wanted air fresheners for 'musty' 15th-century St George's Chapel - Duration: 5:46.

Meghan kicks up a stink: 'Dictatorial' bride wanted air fresheners for 'musty' 15th-century St George's Chapel

Like all brides she wanted every aspect of her wedding to be perfect, not least the venue.

St George's Chapel at Windsor Castle couldn't have been more to Meghan Markle's liking – historic and picturesque with long family ties. it had it all. The only problem was, apparently, the smell.

According to well-placed royal sources, the musty odour of the 15th century chapel did not find favour with the soon to be Duchess of Sussex, who asked for air fresheners to be deployed before her guests arrived.

The same insiders report that Meghan's request to use the atomisers did not find favour with Buckingham Palace, which swiftly pointed out that the chapel was a regular place of worship for the Queen – as it had been for successive monarchs since 1475 – and if it was good enough for them, it would be good enough for her.

The fascinating vignette about the royal wedding on May 19 comes amid speculation about Meghan's friendship with her sister-in-law the Duchess of Cambridge – which is not believed to be close – after it was announced that Meghan and Prince Harry are to move out of Kensington Palace to live in Frogmore Cottage, Windsor, early next year.

There have also been suggestions that Meghan and Harry are proving unpopular with royal staff, and can be difficult and 'dictatorial'.

Recent reports have suggested that despite Harry telling staff 'What Meghan wants, Meghan gets', they also clashed with the Queen's household over which tiara Meghan could wear, until the Queen stepped in.

She was also said to have warned her grandson about their behaviour.

It is understood that the request to use the atomisers – hand-held devices for spraying water or perfume – to create a pleasant aroma for guests at St George's Chapel specifically came from Meghan's office at Kensington Palace.

Although she and Harry organised the wedding themselves with an in-house team, anything to do with the chapel – the venue for several royal marriages including Queen Victoria's and burial place of ten monarchs – is a matter for the Queen, who had to give them permission to use it.

That meant all of the arrangements needed to be passed by the Lord Chamberlain's Office at Buckingham Palace, which is in charge of ceremonial matters such as state visits and garden parties.

And when the request to use the atomisers was raised, the response was, well, a little sniffy.

The source said: 'Apparently Meghan didn't like the smell of the chapel, which, as you would expect, is a little musty. It's not unpleasant at all, though.

'It just smells how you would expect an old building to smell. And that's something the Royal Family are particularly used to.

Meghan wanted staff to go around with these atomisers, like spritzer guns, and spray the chapel with scent before anyone arrived.

'Royal Household staff stepped in and told her office politely, but firmly, that this was the Queen's Chapel and it simply wasn't appropriate.

'I don't believe they said no because they thought it could affect the chapel in any way. It was simply the principle of the thing.

'This is a place that has held royal weddings, funerals and even contains the Royal Vault. I don't believe a request of that nature had been made before.'.

The source stressed there had been 'no falling out' between the two households, but that there was a certain amount of surprise at the request. 'Frankly it was all a bit ridiculous and rather over the top,' they said.

A second source, while also confirming that atomisers had been requested, said: 'The two households worked very well together. I don't believe they [the atomisers] caused concern.'.

St George's Chapel was built by successive monarchs starting with Edward IV in 1475 and completed by Henry VIII in 1528. Kensington Palace declined to comment last night.

For more infomation >> Meghan kicks up a stink: Bride wanted air fresheners for 'musty' 15th-century St George's Chapel - Duration: 5:46.

-------------------------------------------

Safety Tips for the McAllen Holiday Parade - Duration: 1:57.

For more infomation >> Safety Tips for the McAllen Holiday Parade - Duration: 1:57.

-------------------------------------------

Desperate search for missing toddler - Duration: 0:52.

For more infomation >> Desperate search for missing toddler - Duration: 0:52.

-------------------------------------------

PREVIEW 3: Fresno State faces off against Boise State for Mountain West Championship title - Duration: 2:02.

For more infomation >> PREVIEW 3: Fresno State faces off against Boise State for Mountain West Championship title - Duration: 2:02.

-------------------------------------------

Noel Acadian Au Village opens for the holidays, shining a light on LARC - Duration: 2:17.

For more infomation >> Noel Acadian Au Village opens for the holidays, shining a light on LARC - Duration: 2:17.

-------------------------------------------

Preparations underway for Stockton's annual lighted boat parade - Duration: 1:38.

For more infomation >> Preparations underway for Stockton's annual lighted boat parade - Duration: 1:38.

-------------------------------------------

#HandKnottedCarpets for Sale - Duration: 0:39.

Welcome do business with YILONG. With YILONG, your money in safe, your business in safe.

Không có nhận xét nào:

Đăng nhận xét