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Author: Subject: Synthesis of longer chain tertiary alcohols
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[*] posted on 10-1-2011 at 11:10


Good work GC! I always suspected that with some reflux the bromide/H2SO4(aq) system would work the same as HBr(aq) also for longer alcohols. Nice to see it does, as bromides are much easier to come by than HBr. The yield is good probably only because of lower losses due to lower volatility. My yield of 1-bromo-3-phenylpropane was also thereabout, even after vacuum distillation and completely pure by 1H NMR (no alcohol, alkene, ether or isomers). So refluxing in in highly acidic media does no damage in this reaction. Though, the fuming of your product indicates perhaps there is still some HBr inside. In my opinion, this should not prevent the magnesium insertion initiation. The HBr should even etch the Mg surface for better reaction with n-BuBr.
Please post your results in Prepublication section if you ever manage to make the whole preparation till 2-methyl-2-hexanol.




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[*] posted on 10-1-2011 at 11:25


I did not take pictures of the BuBr synthesis- there is nothing really special to it, it went completely according to textbook.

When I make the grignard I will take pictures since you showed interest.

The lower volatility of BuBr is certainly an important factor that gives improved yields compared to EtBr. Every distillation of EtBr entails significant losses to the atmosphere.
But I also felt that the reaction itself went much faster with BuBr since the reaction temperature was higher.
EtBr forms only slowly in the boiling reaction mixture, requiring slow distillation over 6 hours or more.
With BuBr the alcohol has a higher boiling point and allows a higher reaction temperature to be reached which seems to be beneficial.




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[*] posted on 16-1-2011 at 14:10


I have a cheap precursor to 1-dodecene, namely lauryldimethylamine oxide:

http://en.wikipedia.org/wiki/Lauryldimethylamine_oxide

… which upon mere heating snips off the amine base to yield 1-dodecene (Cope reaction).

Now I’m wondering if that can be converted to 1-bromodecane fairly easily (or is this a case of 'close but no cigar'?) I’ve been reading up on anti-markovnikov hydrobrominations (requiring peroxide (!) catalysis) to force the halogen into 1- position. I'm guessing that by 'peroxide' here has to be understood the real deal, i.e. organic peroxides.

Anybody here have some sound ideas? SM searches on ‘markovnikov’ or ‘anti-markovnikov’ yielded little of any use.

I can get a litre of lauryldimethylamine oxide for 4 quid, sounds too good to pass up...

[Edited on 16-1-2011 by blogfast25]
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[*] posted on 16-1-2011 at 14:22


Today I tried to make Na/K alloy in Dioxane.
The potassium coalesces perfectly in the hot solvent, but the Na/K alloy stubbornly refuses to do the same! It just forms shiny drops that divide into smaller drops as the vial is swirled, but the drops never unite to bigger ones at any temperature, not even when squeezed together with a spatula. Very annoying.
It might have something to do with the fact that I used dioxane that is probably saturated with KOH. The next time I will use fresh solvent.
The synthesis of tert-heptanol has to wait until I have made Na/K alloy and dried my ether with it.




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[*] posted on 19-1-2011 at 08:49


Methyl nonyl ketone (2-undecanone) and to lesser extent methyl heptyl ketone (2-nonanone) are the prime ingredients (>90 %) of the essential oil ‘Rue oil’ (aka Ruda or Ruta oil, an essential oil derived from Ruta graveolens). Very OTC but not very cheap…

Precursors to 2-methyl undecan-2-ol and 2-methyl nonan-2-ol.
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[*] posted on 19-1-2011 at 14:52


I now made the Na/K alloy in fresh dioxane, but found that dioxane is not very suitable for coalescing sodium or Na/K alloy. Molten sodium does not lose its crust in dioxane and I had to hold the solid sodium into the molten potassium for over a minute until it started to dissolve. I did not swirl the flask in order to not divide the liquid alloy into smaller droplets, and sucked the alloy into a 2ml syringe for easy dispensing into ether.
So from now on I will make the alloy under kerosene or Shellsol, perhaps with some t-BuOH added.





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[*] posted on 20-1-2011 at 14:04


Very strange how it works for K but not Na or NaK... A bit worrying too: I was hoping to use dioxane (assuming I can get my hands on some!) for any 'chemical' Na ('pok's thread'). You are certain it works well for K, yes?
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[*] posted on 22-1-2011 at 09:12


I’m having considerable trouble getting hold of most of the materials I identified above. As usual the Big Boys aren’t willing to sell to t’Little Guy. No tetrahydro myrcenol, n-octanol or n-hexanol, nor derivatives neither. Of these alcohols many are used in food flavourings/fragrances as esters (often acetates) but are hard to obtain as pure substances. The only one I’ve found from a supplier that sells OTC is (quite expensive) amyl (pentyl) acetate from Kremer Pigments (G.) That can be converted to n-pentanol, then n-chloropentane, then used as Grignard on acetone to yield 2-methyl-2-heptanol.

Kremer also sells cyclohexanol which after bromination could be used as Grignard to yield 2-cyclohexyl-2-propanol. Not sure whether the sodium alkoxide would be well soluble in Shellsol D70 or similar.

Then there’s ‘essential oil of rue’ (OTC but not cheap), supposedly containing mainly methyl octyl ketone and methyl heptyl ketone. These should be purifiable with steam distillation and MgSO4 drying, and Grignarded with MeI to 2-methyl-2-alkanol or with EtBr to 3-ethyl-3-alkanol.

And isopropyl myristate as the organic phase of ‘Dentyl’ mouth wash can be double Grignarded (that becomes expensive) with MeI to 2-methyl-2-alkanol or with EtBr to 3-ethyl-3-alkanol. Very long chain alcohols…

Fractionated coconut oil is a triglyceride of mainly C8 and C10 fatty acids, which could be double Gignarded with MeI to 2-methyl-2-alkanols or with EtBr to 3-ethyl-3-alkanols. Alternatively, saponify, isolate the fatty acids, re-esterify to methyl esters and double Grignard these.


Also, pentyl magnesium chloride as an alkylating agent used on MEK would yield 3-methyl octan-3-ol, a fairly long chain tertiary 3-methyl-3-alkanol...

[Edited on 23-1-2011 by blogfast25]
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[*] posted on 26-2-2011 at 11:32


Thanks to ScienceSquirrel and IPN over at the potassium thread:

http://www.sciencemadness.org/talk/viewthread.php?tid=14970&...

… another useful idea has emerged: synth. of the tertiary alcohol α-terpineol: http://en.wikipedia.org/wiki/Terpineol

Acc. several literature references hydration of α-pinene in excess acetone in the presence of dilute sulphuric acid at 80-85 C oil bath leads to terpineol being formed. The excellent *.pdf unearthed by IPN (first link above) gives several examples. One example cited involves 2 g of turpentine oil (source of pinenes and VERY OTC), 4 ml of a 15 v/v% H2SO4 solution in an excess of 25 ml of acetone, with maximum conversion of pinenes to terpineols occurring at about 4 h at 80-85 C.

Ideas for work up (essentially elimination of the excess acetone) of the terpineol from organic wizzkids here would be much appreciated…
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[*] posted on 27-2-2011 at 03:03


I would suggest;

1) add the reaction mixture to water / ice / diethyl ether

2) wash with sodium carbonate

3) dry and distill
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[*] posted on 27-2-2011 at 05:47


Skip step 1? Just neutralize acid, remove alcohol or acetone solvent that was used to make turpentine miscible with water. The terpineol boils at about 220 C. Another approach might be to make terpin hydrate, then dehydrate that to terpineol in refluxing glacial acetic acid or dilute phosphoric. Terpin may be worth a try too.
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[*] posted on 27-2-2011 at 08:12


The folks from ‘The Good Scents Company’ tend to be quite useful for stuff that’s used in perfumery or as food additives (data on α-terpineol):

http://www.thegoodscentscompany.com/data/rw1011251.html

It would appear to be only slightly soluble in water. How about, after neutralisation, steam distillation to get rid of the acetone (is terpineol actually soluble in acetone?) and possible also other low boiling contaminants?

Some of the stuff that accompanies the α-terpineol seems harmless enough for the product’s purpose but it would be nice to get to at least > 90 % purity, if only to be sure how much you’re using when dispensing it. So how about maybe a few solvent extractions with low boiling solvents like DCM and maybe others to try and extract a maximum of the junk? Steam distil again to get rid of these solvents…

ScienceSquirrel: what’s the idea behind the ether?

Ecclectic: isn’t glacial acetic acid refluxing likely to lead to acetates of α-terpineol? The pinenes lead to acetates with glacial acetic acid (see Wiki on pinenes) which may be the other route: turps + glacial acetic acid -> terpineol acetate. De-esterify to alcohol.
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[*] posted on 27-2-2011 at 13:20


I found a few routes to terpineol googleing terpineol with terpin hydrate.
At least one recommended refluxing terpin hydrate with glacial acetic acid, another with dilute phosphoric.
Terpin hydrate itself might work, and is easy to isolate from turpentine as crystals.

Things what can be made from turpentine seems almost as interesting as makin' potassium!

[Edited on 2-27-2011 by Eclectic]
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[*] posted on 1-3-2011 at 16:24


I bring you a painfully cheap solution to your woes! Shipping is rather slow, I warn you.

http://www.newdirectionsaromatics.com/dimethyl-benzyl-carbin...

This stuff is cheap as dirt! For those not up on their old style names, it's 1,1-dimethyl-2-phenylethanol.

[Edited on 3-2-11 by UnintentionalChaos]




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[*] posted on 1-3-2011 at 19:46


great find, i'm getting it.... like now!
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[*] posted on 1-3-2011 at 23:07


http://www.thegoodscentscompany.com/msds/md101937.html lists the b.p. as 215.

For some reason the MSDS from new directions lists a much lower b.p. I suspect this was under reduced pressure (and they missed listing this). I'd find it very hard to believe 108C given that unsubstituted 2-phenylethanol boils at 219C.

Although it may not be worth the effort for everyone else, I am still interested in alpha-terpineol since I like scents and it can be made from limonene (almost all of orange essential oil, which you can also distill yourself from orange peels). Relevant paper attached

[Edited on 3-2-11 by UnintentionalChaos]

Attachment: op068012d.pdf (33kB)
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[*] posted on 2-3-2011 at 09:10


UC: well done that man!

1,1-dimethyl-2-phenylethanol at lookchem:

http://www.lookchem.com/cas-100/100-86-7.html

This is indeed very similar to the 2-methyl-alkan-2-ol desired structure. And the phenol func. comes bearing promise of possible further functionalisation too. Now I need a source in Europe, this is too good to pass up. And yes, atm. BP must be > 200 C, which is great!

On the limonene -> alfa-terpineol route: trifluoroacetic acid is a bit of an obstacle.

You sure orange essential oil is mainly limonene?



[Edited on 2-3-2011 by blogfast25]
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[*] posted on 2-3-2011 at 09:47


Quote: Originally posted by UnintentionalChaos  
For some reason the MSDS from new directions lists a much lower b.p. I suspect this was under reduced pressure (and they missed listing this). I'd find it very hard to believe 108C given that unsubstituted 2-phenylethanol boils at 219C.

108°C is at ~13 mmHg. I wonder how easily the thing does elimination?
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[*] posted on 2-3-2011 at 09:50


Quote: Originally posted by blogfast25  

You sure orange essential oil is mainly limonene?


http://www.newdirectionsaromatics.com/msds/orangesweetmsds.h...

http://www.newdirectionsaromatics.com/msds/orangesweetgc.htm

http://en.wikipedia.org/wiki/Orange_oil

Attachment: isolating natural compounds.pdf (53kB)
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[*] posted on 2-3-2011 at 13:18


@ UC:

Thanks for nuttin’: now I won’t be able to eat an orange w/o trying to imagine a way to convert the limonene to terpineol but using no CF3COOH! :D (come on organic wizzkids!)

Interesting *.pdf too…


That New Direction Aromatics shop sells other interesting stuff:

Neryl actetate: an unsaturated long chain acetate:

http://www.thegoodscentscompany.com/data/rw1033551.html

‘Octanyl’ acetate: they mean octyl acetate:

http://www.newdirectionsaromatics.com/msds/octanylacetate.ht...

Both are precursors to long alcohols, that could be chlorinated or brominated to Grignard reagents for alkylation of acetone to 2-methyl-2-ol type t-alcohols….

Even linalool is a t-alcohol that would be worth just testing for K-synth. if I could get my hands on some:

http://en.wikipedia.org/wiki/Linalool

[Edited on 2-3-2011 by blogfast25]
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[*] posted on 3-3-2011 at 07:51


Could someone with a reflux/distillation setup try refluxing equal parts turpentine and glacial acetic acid with 1 drop of sulfuric for 4-24 hours, followed by distilling off any excess acetic acid and neutralizing the residue with NaHCO3/water? Floral scent would indicate terpineol and/or it's acetate, citrus would mean it went all the way to limonene.
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[*] posted on 3-3-2011 at 20:46


i tried ordering the carbinol, but they said it would be on back-order for 6+ weeks or so. Anyone else had any luck getting from them?
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[*] posted on 3-3-2011 at 23:54


@Blogfast, use formic acid, it is the very old way of doing this. Chloroacetic acid also works. Oxalic acid may work as well.
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[*] posted on 4-3-2011 at 07:41


Quote: Originally posted by NurdRage  
i tried ordering the carbinol, but they said it would be on back-order for 6+ weeks or so. Anyone else had any luck getting from them?


In theory they ship to outside N.America but looking at the conditions it’s not worth doing. I’m looking for a similar business in Europe but no luck so far…

Quote: Originally posted by smuv  
@Blogfast, use formic acid, it is the very old way of doing this. Chloroacetic acid also works. Oxalic acid may work as well.


You have any references for that? It would be great if formic acid worked…
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[*] posted on 4-3-2011 at 09:41


@b Unfortunately I don't have anything specific on-hand (I definitely would have posted it if I did ;)). I do know it works, it was an old way of determining where the double bond in natural products was located. Why not run a google books search and see what comes up; definitely confine your search to older literature.

Also, the reason why these acids work, and carboxylic acids like acetic acid don't, is that formic and chloroacetic acid are strong enough to protonate the alkene, giving a carbocation which is vulnerable for attack by the formed carboxylate. Trifluoroacetic acid works in the same way, but it is way overkill, acetic acid on the other hand, just is not acidic enough to protonate the alkene.

All this being said, it is possible that if you reflux the stuff in glacial acetic acid, with a catalytic amount of H2SO4, you may get addition to the double bond.

[Edited on 3-4-2011 by smuv]
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