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Author: Subject: Synthesis of longer chain tertiary alcohols
blogfast25
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[*] posted on 31-8-2016 at 06:53


@CuReUS:

We don't need a diol. We need a 2,2-dimethyl something-2-ol.

@aga:

Limonene has been considered. Buy it pure on eBay, cheap as chips. Just about every toilet cleaner/oven cleaner/bathroom cleaner/etc contains it, it gives these concoctions its 'natural' (LOL) citrussy odour.

Will revisit the possibility of turning this into a 2,2-dimethyl something-2-ol. Hydration of limonene leads to a mixture of terpineol isomer though. Hard to separate.

Memory lane:

Here's the original post in which I proposed an OC research project for aga:

http://www.sciencemadness.org/talk/viewthread.php?tid=62973&...

Halcyon days...
<hr>

Having said all that I'm now inclined to 'cut out the middleman' and purchase the alpha-terpineol:

https://shop.perfumersapprentice.com/p-6228-terpineol-alpha.... (thanks Alice!)

And play with that.

* Characterise
* Attempt to hydrogenate (Pd/C + ammonium formate)
* Attempt to isomerise to tetrahydro myrcenol (2,6-dimethyloctan-2-ol)


[Edited on 31-8-2016 by blogfast25]




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[*] posted on 31-8-2016 at 07:21


Quote: Originally posted by blogfast25  
Personally I very much like the idea of a 2-methyl-2-alkanol with total chain length around C10. These could be Grignarded with MeMgBr on linear long chain alkanoates, with ‘alka ≈ C10’. They would have the same ‘active site’ (2-methyl-2ol) as t-butanol but a medium-long paraffinic tail for solubility in alkanes/napthenics.
Not sure if this is still relevant as I haven't read every page of this thread, but I have the materials to make such an alcohol, 2-methyl-2-octanol, by the Grignard reaction of 2-octanone (which I made previously) and methylmagnesium iodide. Longer chain options that aren't 2-methyl-2-ols but could be prepared just as easily include 3-methyl-3-nonanol (substitute ethylmagnesium iodide) and 4-methyl-4-decanol (substitute n-propylmagnesium bromide).



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[*] posted on 31-8-2016 at 07:29


Oh, still very relevant - we've failed to make anything so far !

Please, dive into the synth immediately and see what you get.

It'd be great if you could post a link to a ref, or even an outline of the process.

I'll try to copy it if i have the reagents.




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[*] posted on 31-8-2016 at 07:32


Quote: Originally posted by zts16  
Quote: Originally posted by blogfast25  
Personally I very much like the idea of a 2-methyl-2-alkanol with total chain length around C10. These could be Grignarded with MeMgBr on linear long chain alkanoates, with ‘alka ≈ C10’. They would have the same ‘active site’ (2-methyl-2ol) as t-butanol but a medium-long paraffinic tail for solubility in alkanes/napthenics.
Not sure if this is still relevant as I haven't read every page of this thread, but I have the materials to make such an alcohol, 2-methyl-2-octanol, by the Grignard reaction of 2-octanone (which I made previously) and methylmagnesium iodide. Longer chain options that aren't 2-methyl-2-ols but could be prepared just as easily include 3-methyl-3-nonanol (substitute ethylmagnesium iodide) and 4-methyl-4-decanol (substitute n-propylmagnesium bromide).


I've since come back a little bit from the C10 requirement, which I fear may be a little too long.

Understand the function of the carbinol catalyst in the reduction of KOH by Mg (powder, filings). The t-alcohol side of things is the reactive side, forming the K alkanoate (KOR). The dangling alkyl group R is supposed to provide solubility in the alkane solvent. So far, so simple.

I fear that too long alkyl groups may reduce reaction speed due to steric hindrance. For that reason, my ideal candidate would be around C6, in my current thinking.

The simple truth is that this is all guestimated speculation and that we simply will never know without testing the candidate catalyst in a real experiment.

Who knows. Maybe a C10 is the answer to all problems? Test, test, test!

[Edited on 31-8-2016 by blogfast25]




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[*] posted on 31-8-2016 at 07:37


@aga: I might try it this weekend when I'm home. I don't know yet, as there's a lot of other stuff that I want to do, but it would make a good video.

Quote: Originally posted by blogfast25  
I've since come back a little bit from the C10 requirement, which I fear may be a little too long.

Understand the function of the carbinol catalyst in the reduction of KOH by Mg (powder, filings). The t-alcohol side of things is the reactive side, forming the K alkanoate (KOR). The dangling alkyl group R is supposed to provide solubility in the alkane solvent. So far, so simple.

I fear that too long alkyl groups may reduce reaction speed due to steric hindrance. For that reason, my ideal candidate would be around C6, in my current thinking.

The simple truth is that this is all guestimated speculation and that we simply will never know without testing the candidate catalyst in a real experiment.

Who knows. Maybe a C10 is the answer to all problems? Test, test, test!
In that case, I think that C8 would be a good place to start, especially since it would be in the 2-methyl-2-ol form. I could prepare the other two that I mentioned and compare, though I would probably have to prepare more 2-octanone to do this, and it would take considerably longer because of that and the fact that my lab time is very limited now. This weekend if everything goes to plan, I'll prepare methyl iodide and do the Grignard. I'll record it and edit the footage over the next week.

[Edited on 8-31-2016 by zts16]




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[*] posted on 31-8-2016 at 08:40


Quote:
Having said all that I'm now inclined to 'cut out the middleman' and purchase the alpha-terpineol (thanks Alice!)


You're welcome, but before you order have a look at those two:

http://shop.perfumersapprentice.com/p-6061-dimetol-g.aspx

http://shop.perfumersapprentice.com/p-6058-dimethyl-phenyl-e...

[Edited on 31-8-2016 by Alice]
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[*] posted on 1-9-2016 at 04:32


Quote: Originally posted by blogfast25  
@CuReUS:
We don't need a diol. We need a 2,2-dimethyl something-2-ol.

I don't mean to be rude but even after going through the whole thread I still don't know what you need.There are talks about turps,TCCA,chloral,banana oil,camphor,limonene,cat repellent.And no one had been able to prepare any of the above mentioned compounds to test whether they work at all !!!
so saying that "we don't need a diol" would be going a bit far,don't you think ? ,when you don't even know if the tert-OH would work or not ?
Quote:
Having said all that I'm now inclined to 'cut out the middleman' and purchase the alpha-terpineol:
* Attempt to hydrogenate (Pd/C + ammonium formate)

do you have a reference for that ?
I found two references for the hydrogenation of terpineol. Both the papers are by the same author but both the articles are in german.:(
http://onlinelibrary.wiley.com/doi/10.1002/jlac.19113810105/... - "colloidal Pd" on pg 69
http://onlinelibrary.wiley.com/doi/10.1002/jlac.19144030107/... - "Pd catalyst " on pg 101
I had another question. Suppose you started with limonene,you could put the OH on the side chain to make terpineol and reduce the cyclic double bond or you could reduce the alkene side chain and put the OH on the ring.
would doing the latter give any advantage over the former ?
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[*] posted on 1-9-2016 at 05:10


Quote: Originally posted by CuReUS  
I. [...] ,when you don't even know if the tert-OH would work or not ?
Quote:
Having said all that I'm now inclined to 'cut out the middleman' and purchase the alpha-terpineol:
* Attempt to hydrogenate (Pd/C + ammonium formate)

do you have a reference for that ?
I found two references for the hydrogenation of terpineol. Both the papers are by the same author but both the articles are in german.:(
http://onlinelibrary.wiley.com/doi/10.1002/jlac.19113810105/... - "colloidal Pd" on pg 69
http://onlinelibrary.wiley.com/doi/10.1002/jlac.19144030107/... - "Pd catalyst " on pg 101

II. I had another question. Suppose you started with limonene,you could put the OH on the side chain to make terpineol and reduce the cyclic double bond or you could reduce the alkene side chain and put the OH on the ring.
would doing the latter give any advantage over the former ?


I. We have two t-alcohols that work as catalysts in KOH/Mg reactions, both tried and tested: t-butanol and 2-methyl-butan-2-ol. We also know why these work. So we logically assume that longer chain alcohols with the same type of reactive site will work too.

Primary diols BTW wouldn't last in that cauldron, just like primary and secondary alcohols don't. Only t-alcohols are stable enough, in these high temp. alkaline conditions.

II. Hydration of limonene mostly puts the OH in the side-group. The remaining double bound (in the ring) could be hydrogenated or cracked open to give a longer t-alcohol.

Thanks for the hydrogenation links! :) I have plenty references for Pd/C+ammonium formate hydrogenations of simple molecules, it's a very effective method.

[Edited on 1-9-2016 by blogfast25]




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[*] posted on 1-9-2016 at 22:10


Quote: Originally posted by CuReUS  
Why not get limonene instead of terpineol and then add two moles of H2O to it to get a diol

Quote: Originally posted by blogfast25  

Primary diols BTW wouldn't last in that cauldron, just like primary and secondary alcohols don't. Only t-alcohols are stable enough, in these high temp. alkaline conditions.
II. Hydration of limonene mostly puts the OH in the side-group

I understand the confusion now.By diol I had meant a molecule with two OH groups attached to it,not two OH groups adjacent to each other like a glycol
what I meant by double hydration of limonene was putting two molecules of water in limonene,one on the side chain double bond and the other on the ring double bond to get 2 t-butyl OH groups !!!
the name of the compound formed after double hydration of limonene is 1,8-terpin ( CAS no-80-53-5) http://www.chemblink.com/products/80-53-5.htm
I have found a reference to do just that but I can't find the article,so pls find it someone:(

ref - Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences, , vol. 89, p. 361

[Edited on 2-9-2016 by CuReUS]
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[*] posted on 2-9-2016 at 00:11


@CuReUS.

Comptes rendus hebdomadaires des séances de l'Académie des Sciences:

http://gallica.bnf.fr/ark:/12148/cb343481087/date
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[*] posted on 4-9-2016 at 13:29


I made methyl iodide today, so I'm all set for the Grignard, and could do it tomorrow. However, the humidity in my lab right now is about 70%, so it may not be prudent.

IMG_6742.jpg - 1.8MB




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[*] posted on 4-9-2016 at 14:14


Prudence is for Business or Politics.

If the yield is low, you already got a reason why.

Go for it zts16 !




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[*] posted on 4-9-2016 at 14:21


But also, if the yield is low I'll end up wasting two valuable reagents that I had to make myself, and then I'll have a lot of work to do before I have a chance to try again. I want to have enough 2-methyl-2-octanol to allow for a couple of tries at the sodium reaction.



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[*] posted on 4-9-2016 at 15:07


Quote: Originally posted by zts16  
But also, if the yield is low I'll end up wasting two valuable reagents that I had to make myself, and then I'll have a lot of work to do before I have a chance to try again. I want to have enough 2-methyl-2-octanol to allow for a couple of tries at the sodium reaction.


Unless you have experience with the KOH/Mg reduction with the standard catalyst (t-butanol) it would be prudent to evaluate the 'new' carbinol back-to-back with t-butanol. The reduction has defied some of our best experimeters, notably garagechemist who had several fails before getting K. A 'negative' with the new catalyst may thus not necessarily be meaningful.




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[*] posted on 4-9-2016 at 15:54


I totally agree. In fact, yesterday I went on eBay and ordered some t-butanol so that I could try the potassium version of the reaction myself and become comfortable with it before I begin playing with sodium.



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[*] posted on 4-9-2016 at 16:28


Quote: Originally posted by zts16  
I totally agree. In fact, yesterday I went on eBay and ordered some t-butanol so that I could try the potassium version of the reaction myself and become comfortable with it before I begin playing with sodium.


Excellent. Thanks for getting this thread moving again.

If your longer carbinol works for K then it certainly would be worth trying for NaOH/Mg.

[Edited on 5-9-2016 by blogfast25]




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[*] posted on 24-9-2016 at 13:11


I'm happy to say that today I finally got around to running the Grignard, and have successfully prepared almost 5 mL of what should be 2-methyl-2-octanol.

I also recently received a liter of t-butanol from eBay, so now I can try the control reaction that we're all familiar with to make sure that I'm able to get it to work before I start experimenting with the new alcohol.




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[*] posted on 24-9-2016 at 14:40


Coool !

Photos ! Write-up !

Any difficulties with it or was it do-able for most of us ?




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[*] posted on 24-9-2016 at 14:48


As I previously said I would, I recorded the reaction. A video will be posted to YouTube once the editing is completed, probably later this week.

It was actually a lot easier than I had anticipated.




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[*] posted on 24-9-2016 at 15:18


So, el Gringo is actually not the big bad hard-ass it's Rep says it is ?

C'mon. Details dude !

OK. A proper write-up would be better, but that takes time.

If you could maybe dangle a dollop of hope to us Grignard-virgins, that'd be good.




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[*] posted on 24-9-2016 at 15:29


Well, it was 76% humidity today, I didn't flame dry the glassware, and I used ether that I distilled directly from starting fluid without any additional drying. If I was to assume that my crude product was actually pure 2-methyl-2-octanol, I would have gotten a 79% yield. But I know that there are impurities because it is slightly yellow and smells slightly like 2-octanone. I don't want to try and remove these impurities because I have such a small volume that it may not leave me with enough to use. If I find out that I'm allowed to, I might take a tiny sample of it to school with me and see if I can run it in the GC/MS.



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[*] posted on 6-10-2016 at 12:57


Quote: Originally posted by zts16  
If I find out that I'm allowed to, I might take a tiny sample of it to school with me and see if I can run it in the GC/MS.


That would be great.




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[*] posted on 18-11-2016 at 16:52


How about acetone plus n-hexyl Grignard? That would give you the same product. How much material would you need for the best chances of having it work? Just curious.
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[*] posted on 24-12-2016 at 15:10


Isn't that the final product you want to get out of the whole terpineol action?:

http://www.hekserij.nl/Parfum_en_Geur/Aromachemicalien/Dihyd...

Not that isolating α-pinene from turpentine and converting it in several steps to a 2,2-dimethyl-something-2-ol would be an interesting project by itself, but a few € could contribute significantly to the main (pottasium) project's progress...

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[*] posted on 30-12-2016 at 23:01


Quote: Originally posted by Dr.Bob  
How about acetone plus n-hexyl Grignard? That would give you the same product. How much material would you need for the best chances of having it work? Just curious.
I don't have hexanol, so I wouldn't be able to do that, but I could make an even longer alcohol with n-octyl Grignard and acetone (2-methyl-2-decanol). That may be too long though.

Also, I would be happy to prepare more of both alcohols and send them to someone more proficient at the potassium reaction than I am to try out. My interest is purely theoretical here because I have plenty of sodium metal, and I am more focused on organic syntheses than inorganic chemistry. It seems to me like this would be a good collaborative project.




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