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Author: Subject: Synthesis of longer chain tertiary alcohols
CuReUS
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[*] posted on 17-10-2014 at 08:32


but we have to use lithium ,as your grignard is too heavy and bulky ,not Lively and Light like Lithium

but about using organo zinc?
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[*] posted on 4-1-2015 at 01:22


Depending on what did you use sodium alcoholate with corresponding alcohol solvent. Sodium alcohol itself is alkaline, so we shouldn't use alkali. Directly drops allyl chloride into the sodium alcohol, and allyl chloride activity was so high, reaction would be very quickly.
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[*] posted on 15-2-2015 at 08:49


Quote: Originally posted by maleic  
Depending on what did you use sodium alcoholate with corresponding alcohol solvent. Sodium alcohol itself is alkaline, so we shouldn't use alkali. Directly drops allyl chloride into the sodium alcohol, and allyl chloride activity was so high, reaction would be very quickly.


I've kind of lost track of this thread a bit.

What is the projected reaction product between sodium ethoxide and allyl chloride?




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[*] posted on 15-2-2015 at 10:59


Sounds like a Williamson ether synthesis to me.



As below, so above.

My blog: https://denovo.substack.com
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[*] posted on 13-5-2015 at 15:00


So did anybody have success in manufacturing higher tertiary alcohols and use in making potassium?
I don't see any reason why it shouldn't work.
When I think about tertiary alcohols, camphor and some alkyl grignard comes to my mind. Ketones in general would be less reagent consuming than esters.
How many moles are required for one mole of potassium? :D
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[*] posted on 13-5-2015 at 15:31


Quote: Originally posted by Alice  
So did anybody have success in manufacturing higher tertiary alcohols and use in making potassium?
I don't see any reason why it shouldn't work.
When I think about tertiary alcohols, camphor and some alkyl grignard comes to my mind. Ketones in general would be less reagent consuming than esters.
How many moles are required for one mole of potassium? :D


No, no success has been reported so far.

About 0.1 mol alcohol is needed per mol of K.




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[*] posted on 13-5-2015 at 16:23


Quote: Originally posted by blogfast25  

No, no success has been reported so far.

About 0.1 mol alcohol is needed per mol of K.


Thank you very much for the answer.
10 mol% is a fairly good efficiency.

Here I found a reference for camphor reactions with grignards: http://onlinelibrary.wiley.com/doi/10.1002/ffj.2730060102/abstract

Yields don't seem fantastic. The authors claim that grignard reduction is a major side reaction. Interesting to know, though.

[Edited on 14-5-2015 by Alice]
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[*] posted on 13-5-2015 at 18:07


Quote: Originally posted by Alice  
10 mol% is a fairly good efficiency.

Here I found a reference for camphor reactions with grignards: http://onlinelibrary.wiley.com/doi/10.1002/ffj.2730060102/abstract



Well, it is a catalyst.

I'll have a look at your link later.




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[*] posted on 14-5-2015 at 10:08


Alice:

A ‘bulky’, camphor-like t-alcohol could be a great idea.

Remember that the purpose [in this context] of these ‘longer C’ t-alcohols is mainly to prepare sodium t-alkoxides of higher solubility in paraffinic solvents. We believe that lower solubility of sodium alkoxides (compared to K equivalents) is the cause of the very long reaction times (in the case of the reduction of NaOH with Mg in inert solvent)

The obvious potential drawback is steric hindrance: the reduction rate of a bulky sodium alkoxide (by Mg to Na and Mg alkoxide) may be slower than with a smaller Na t-alkoxide. That would be swings and roundabouts.

A request for access to the paper you linked to has now been made.


[Edited on 14-5-2015 by blogfast25]




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[*] posted on 15-5-2015 at 05:42


From that paper:

http://www.sciencemadness.org/talk/viewthread.php?tid=62326#...

Preparations of Alkyl Isoborneols and Alkyl Borneols

Quote:
Preparation of the Alkyl Isoborneols 9a-19a,
21a-26a and Alkyl Borneols 19&22b, 24b, General
Procedure

2.43 g (100 mmol) of Mg turnings were covered
with 10ml of ether, and some drops of the total
amount of 100 mmol of the respective alkyl halide
(see above) was added. After starting the reaction
the mixture was cooled with ice-water, and the
alkyl halide solution in 25 ml of ether was added
with stirring in such a manner that the temperature
remained below 15°C. After stirring for 30 min at
room temperature a solution of 35mmol of the
respective ketone 1-4 in 25 ml of ether was added
dropwise. The mixture was heated under reflux for
one day, then cooled with ice-water, and poured
into 50 ml of saturated NH4Cl solution. Work-up
as above afforded the product which was purified
by FC. Analytical data: see Table 2; 'H-NMR data:
see Table 3; 13C-NMR data: see Table 4.


Quote:
Work up

The mixture was neutralized with dilute hydrochloric acid, the phases were
separated, and the aqueous phase was extracted
three times with ether. The combined organic
phases were washed with water and brine, dried
over MgSO, and concentrated. The product was
purified by FC and distilled (KRD).


9a: 2-methyl isoborneol

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


[Edited on 15-5-2015 by blogfast25]




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[*] posted on 16-5-2015 at 09:45


Here are the literature yields for the camphor derived alcohols:

2-methyl-: 64 %
2-ethyl-: 29 %
2-butyl-: 23 %

I did a little literature research about t-butoxides, and found KOt-Bu forms tetramers with a cubic core made of K and O. NaOt-Bu has two structures, nonamer and hexamer. The hexamer has a hexagonal prism with sodium and oxygen alternating, nonamer has a more complicated irregular structure. http://onlinelibrary.wiley.com/doi/10.1002/cber.19771101018/abstract. The authors state that the bulkyness of the alcohol leads to these ball-like oligomers. In comparison NaOMe gives plane like structures, thus insoluble solids.
This might be a hint why these t-alkoxides have some solubility in nonpolar organic solvents.
The procedure used by the authors for making NaOt-Bu is dissolving Na in a solution of t-BuOH in hexane which gives a cloudy solution.

Now my guess is for 2-metyl-2-hydroxyalkanes the structure might be similar.
This means there might be more than just a difference in basicity and solubility in the K and Na reactions.


The interesting fact is for both structures, hexamer (Na) and tetramer (K) ions and O- are buried. For further reaction with Mg it has to dissociate.


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

An obvious reason why making sodium takes much longer is NaOH beeing a weaker base than KOH and therefor following equilibrium is not favorable for NaOR/nNaOR:

ROH + NaOH -> NaOR + H2O -> NaOR (cluster)

Some further speculations:

O- is the basic agent in alkoxides. The counterion just draws more or less electron density from O- and makes it therefor more or less basic. For all clusters described above O- is completely buried. Once a cluster is formed it will be more difficult (even for water) to access and reprotonate one of the O-. This might be the reason why tertiary alcohols are required. So equilibrium is shifted more towards alkoxide because of said cluster formation.

Which cluster is more stable, K or Na?

For energetic reasons, I'd say Na-clusters are more stable because Na-O ionic bond energy is bigger than K-O.
Kinetics are less favorable for tNa clusters. It takes longer (lower probability) for more alkoxides to meet. Lower solubility for Na alkoxide contributes additionally, of course.

Considering sterics it is hard to believe to get hexamers or nonamers with a camphor derived t-alcohol, because it would be highly crowded. Smaller clusters may be forced, because the angle between alkyl moieties is bigger.

[Edited on 16-5-2015 by Alice]
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[*] posted on 16-5-2015 at 10:09


That's very interesting Alice, thanks for your thoughts on that.

So in your estimation, would pursuing the alkoxides of 2-methyl camphor derived t-alcohols be worth doing? The first test would of course be on K itself. Failure there would render this catalyst unusable for Na.

And on a minor point, when can you start preparing some? :)




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[*] posted on 16-5-2015 at 11:36


Quote: Originally posted by blogfast25  
That's very interesting Alice, thanks for your thoughts on that.


Your welcome.

Quote:
So in your estimation, would pursuing the alkoxides of 2-methyl camphor derived t-alcohols be worth doing? The first test would of course be on K itself. Failure there would render this catalyst unusable for Na.


Good thinking just to change one parameter. From a chemical point of view 2-methyl- would be most interesting, but I won't deal with MeI and I don't want to encourage anyone to deal with it. So 2-ethyl- would most likely be the best choice.

Quote:
And on a minor point, when can you start preparing some? :)


:)

I need some dry ether. :(

Any ideas how to separate borneol and 2-ethyl borneol?

[Edited on 16-5-2015 by Alice]

[Edited on 16-5-2015 by Alice]
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[*] posted on 16-5-2015 at 12:24


Borneol as a side-product? Blimey, good question. I'm not that much of an OC, I'm afraid. Column chromatography? Plenty of possible solvents at least! :D

Would it even hurt to leave it in there? Secondary alcohols might not be very stable in those conditions though.

Ether: a lot of car starter fluids contain it. Or used to at least.

Are EtI or EtBr that much safer than MeI? No idea...

Different approach: tetrahydromyrcenol. Any thoughts? I have some dihydromyrcenol, so it needs hydrogenating, haven't 'gotten round' to that 'yet' (and now in quite poor health, for the foreseeable future)...

[Edited on 16-5-2015 by blogfast25]




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[*] posted on 20-12-2015 at 12:59
Alpha-pinene distillation from OTC turpentine


Today some OTC Turpentine was distilled in order to extract a quantity of alpha-pinene as a reagent for an upcoming synthesis.

One reference said that 155 C is the boiling point, yet another stated between 90 C and 105 C in a vacuum distillation (torr unstated).

Firstly a 500ml RBF was tried with a Vigreux column and a 300mm Liebig condenser.

When boiling, the turpentine simply refluxed in the boiling pot, with barely any condensation front seen in the column, despite insulation.

Interestingly the condensate ran back to the liquid down the inner wall of the RBF in thin, evenly spaced rivulets, which at times flash-boiled at the top end before re-forming.

Next a 250ml RBF was charged with 190ml of turpentine in a 'normal' distillation setup (no column) with aluminium foil insulation around the RBF and stillhead.

With this apparatus the distillate started coming over at 142 C (25 minutes), although there was still significant refluxing, and the vapour was condensing before it reached the condenser.

The vapour temperature stabilised at 155 C (30 minutes) at which point the distillate was literally pouring into the receiver flask.

Armed with these parameters, it was decided to re-run the distillation with the 'heads' being anything under 155 C, the reference range of 15 C used to determine that the 'bulk' would be distillate between 155 C and 170 C and the 'tails' being anything over 170 C.

The receiving flask was swapped at each of these cut-off points.

More insulation was added to cover the entire stillhead and the side arm, right up to the condenser, then the distillation repeated.

The results were (left to right) :-

20ml 'heads', a clear liquid smelling slightly of emulsion paint.
143ml 'bulk, a sparklingly clear liquid smelling faintly of pine.
14ml 'tails', a clear liquid smelling of nothing apart from a faint hint of alcohol.
4ml 'dregs' (left in the boiling pot) a yellow liquid smelling faintly of pine resin.

turps.JPG - 150kB




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[*] posted on 20-12-2015 at 13:16


Very nice work and write up.

Full disclosure: this is the α-pinene that will hopefully be converted to α-terpineol and its fully saturated equivalent 2-(4-methylcyclohexyl)propan-2-ol.

Hopefully this will make the work-up of the crude α-terpineol easier because of fewer by-products/impurities.





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[*] posted on 20-12-2015 at 13:25


Thanks !

Is 143ml enough, and should that 143ml be re-distilled ?




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[*] posted on 20-12-2015 at 13:47


Nice job aga, 143ml should be plenty for a run of mixed high MW tertiary alcohols. It's actually quite a lot, I wouldn't use more than 25ml for a test run to make sure that everything works as expected. As for redistillation, unless you can push enough heat into the mixture to fractionate it, I don't think it's worth it unless you have some sort of obvious contaminant. Worst case, the trial run is unsuccessful and you can redistill the main batch.



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[*] posted on 20-12-2015 at 14:16


Quote: Originally posted by aga  
Thanks !

Is 143ml enough, and should that 143ml be re-distilled ?


The plan (in your email inbox) calls for 20 ml for the initial test. I don't see a great need for re-distilling what you have there because we have no serious means of determining α-pinene content on it but it's a very reasonable assumption that this distillation increased the α-pinene content in that fraction. That could prove very useful.




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[*] posted on 20-12-2015 at 14:23


For gdflp's information:

The plan is now to go straight to α-terpineol via refluxing of dilute α-pinene in acidic acetone solution. We have an authoritative paper with detailed procedure on it. Will post some more on it when aga starts converting.




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[*] posted on 20-12-2015 at 14:26


Thanks for the latest report from shedworld.

Given that this thread started as a support resource for thhe potassium thread, how suitable will your product be for extracting K? What other uses will you put it to?


edit
Cross post. Thanks for answer anyway. Looking forward to seeing how it all works out.

[Edited on 20-12-2015 by j_sum1]




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[*] posted on 20-12-2015 at 15:53


Quote: Originally posted by j_sum1  
Thanks for the latest report from shedworld.

Given that this thread started as a support resource for thhe potassium thread, how suitable will your product be for extracting K?

[Edited on 20-12-2015 by j_sum1]


The purpose is to test the saturated one as a catalyst in the KOH/Mg reduction, which is why I asked aga to post his distillation results (which were entirely his own initiative) here. And in the case of success, also testing for catalysis of NaOH/Mg reduction.

A second derivative from α-terpineol, i.e. tetrahydro myrcenol (2,6-dimethyl octan-2-ol) may also be attempted to synthesize, for the same purposes.

There's no other goal apart from perhaps a bit of shed-fun! :D

[Edited on 21-12-2015 by blogfast25]




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[*] posted on 20-12-2015 at 16:18


Oh and the procedure for the conversion of α-pinene to α-terpineol you can find here, second *.pdf linked to by UC235:

http://www.sciencemadness.org/talk/viewthread.php?tid=64560#...

Suggestions for work-up are welcome.




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[*] posted on 21-12-2015 at 12:12


Quote: Originally posted by blogfast25  
Will post some more on it when aga starts converting.

Oh ! Right.

That was my Cue then.

Best get started.




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[*] posted on 21-12-2015 at 14:08


Quote: Originally posted by aga  
Quote: Originally posted by blogfast25  
Will post some more on it when aga starts converting.

Oh ! Right.

That was my Cue then.

Best get started.


Have possible reaction mechanism, will travel.

Let's see if the pot doesn't turn black before I opine on it.




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