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Author: Subject: Make Potassium (from versuchschemie.de)
Picric-A
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[*] posted on 22-2-2011 at 10:50


My reflux system is he same as everyone else is using, a 100ml rbf. with q.fit liebig condenser and a baloon on the top with a small hole to prevent as much O2 getting in as possible... i would have thought you could not get any better than this?!
My tests proved that t-BuOH was definitly present in the post reaction paraffin so that definitly was not the problem here...
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[*] posted on 22-2-2011 at 12:35


Quote: Originally posted by Picric-A  
My reflux system is he same as everyone else is using, a 100ml rbf. with q.fit liebig condenser and a baloon on the top with a small hole to prevent as much O2 getting in as possible... i would have thought you could not get any better than this?!


It couldn't, Picric-A, absolultely. So loss of catalyst isn't your problem. I just wanted to ascertain that: job done...
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[*] posted on 22-2-2011 at 15:37


Quote:
My tests proved that t-BuOH was definitly present in the post reaction paraffin so that definitly was not the problem here...


And what tests would these be?
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[*] posted on 23-2-2011 at 14:26


This is not a result... yet. But a suggestion for others in the meantime.

I have recently been sent a small amount of t-butanol and have started rerunning the same setup I used in the post with photographs.

This time, I harvested the magnesium using only a larger drill bit, producing fairly big chips.

As I am using an oil bubbler to close the glass off, I can see the rate of evolution, which you can not do by simply watching the solution alone. On rerunning this, the first thing I noticed was significantly less bubbling before the alcohol was added. Yet I am using precisely the same source of magnesium, KOH and kerosene. The only thing that has changed being the size of the magnesium particles.

The gas evolution had stopped, entirely, within an hour. Comparing that to my first attempt, using smaller particles that had been better mixed together, there is clearly a difference first hand. This to me suggests what is actually happening is that the larger particles are not allowing the KOH to properly dehydrate prior to the alcohol being added; as both those and the water are insoluble (is there anyway to easily promote this perhaps, the transfer of water?). This suggests using powdered magnesium is a good idea in terms of stripping water. As the KOH 'cements' before the alcohol is added, grinding the KOH may not be of much benefit; provided the magnesium ends up will mixed with it when this happens.

I also realised that not only is using an oil trap a good idea in terms of qualitatively determining the evolution rate, but having some method of measuring the gas coming off would also be of use when testing different materials. I think Len mentioned this earlier on, when he determined that it was hydrogen coming off. This would not only show you the rate, but also allow you to determine any changes in that and if the reaction had come to completion or not.

I realised that would be useful after I had started running this second attempt. Growing tired staring at the flask and wishfully hoping to see a blob of potassium appear, I began estimating the size of the bubbles leaving the tube. They were evolving at a constant rate of one per 30 seconds. After estimating the size, I was able to work out the rough volume. Knowing the number of moles of KOH present, and assuming it was perfectly dry when put in, I was able to work out the theoretical quantity of hydrogen it would release, and it's rough volume, then compared that with the rate of evolution.

In total, I calculated it'd be around 56h before the reaction completes.

I then noted that my kerosene is boiling around 40C lower than the 220C of the D70 and the rule of doubling reaction times per 10C drop. Assuming it'd usually take about 3h, that gives a theoretical time of 48h for this one. A difference of just 14% from me eye balling the bubble sizes. I'm very happy with that estimation (take that for a guesstimate Mr. Adam Savage!), but not with the times involved. As both the methods of calculating it yield a painful result.

This also seems to be playing out in the flask, as the magnesium has now darkened (a lot), but I see no blobs that I could confidently claim to be potassium; only tiny fleeting shiny balls the size of pinheads that make me feel happy because they appear to bounce in the torrent of bubbles and go downwards. My solvent is much less dense than the .89 being mentioned earlier, so they will be at the bottom. And I can barely see that with it lifted out of the mantle, let alone with it in it.

I'm not sure what to do with this one. I am now running drastically short on pencil sharpeners to cut holes in, so I would have to order up a bag of magnesium to rerun it.

I am tempted to see if the flask does output something by simply leaving the sucker boiling for two days.

There are some worthwhile things to gain from this however. You certainly need to check the BP of your solvent. It IS going to take forever if it's too far down. Mine's at 180C, and it's demonstrating we're talking days for sure; even more for sure if I end up with it after that time.

It also means my IPA result is potentially wrong, as it was being run at the same temperature and was only done for 9h, a sixth of the 56h I've worked out. Solution? There's no way I can be running multiple tests when it's taking 2 days per go. I'll be ditching this kerosene for the next. Or may try redistilling it to see if there are any components around the 220 mark. I doubt there are, as this is standardised for jet engines, it's likely going to be a lower BP with a somewhat constant number; due to this having an immediate impact on how the fuel vapourises in the engine.

Result

Inconclusive

Prediction

Depending on how long I can keep my hands off the glassware, it may work. Thus far, I am less than 25% of the way through.

Edit
I have just been outside to have another look at it. After watching the bubbler for around 3 minutes, I didn't see a single one leave; only the oil wobbling back and forth as the drips moved around in the glass. I forgot to mention, there is a white, wax like, solid accumulating around the top of the solution and sticking to the glass. It shows no particular interest in melting even thought I've been running it with the mantle turned down, and then tried turning it all the way up to get the surface of the glass hot. I saw traces of this when I first ran it, and it refused to leave even when rinsing or soaking the glass with KOH, sulphuric or hydrochloric. It was like a gel that needed wiping out.

It appears the reaction has either slowed further or simply stopped. I'll leave it until tomorrow and have a look. If it was going to work, I should have trace of it present by then.

I started this at about 1.20 this afternoon, the reflux, and it's now 11.30pm.

[Edited on 23-2-2011 by peach]




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[*] posted on 23-2-2011 at 16:14


I you have time, try distilling off the low boilers from the kerosene? I'd suspect at least 2/3 of the components boil above 210 (or it would not be the kerosene fraction)
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[*] posted on 23-2-2011 at 20:07


peach, you are basically getting the same results as I did, and also garage chemist's and picric acid's. I still think that the right magnesium is key to success.
I know how it feels, I also used to stay for hours by its side, praying to see the gas evolution intensify, or see tiny K balls.
I don't think that it is necessary the percentage purity with the magnesium, but I think that there is one (or several) elements in the magnesium which cause these bad results. This would explain Picric's results, whose Mg ribbon was certified at least 99.9% Mg. Even with such a high purity, if these unwanted elements were in a percentage of , say 0.05%, it's still significant, and would passivate the surface.

I don't know if Len still reads this thread, but if you do, Len, could you please tell us if the magnesium you used for the failed attempt years ago was the same one you used for the successful one?
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[*] posted on 23-2-2011 at 21:31


The Mg I used in my first post up the thread, was what I have in the lab for Grignards. But I have since checked that the Mg from three years ago also works if powdered.

I think the point peach made is absolutely right. The fine Mg is needed to dehydrate the KOH. It does so by contact, as unlike the subsequent K formation reaction, the solvent can not promote dehydration. If you use turnings they do not completely dehydrate the KOH and rapidly dull. This is one source of no reaction, rather than any Mg impurities. Grinding is hardly necessary - the hydrated KOH is liquid at the reaction temperature.

The second source that might be causing the problems is the solvent. It must be saturated, with no olefins or carbohydrates that some paraffins might contain - although aromatics are allowed. It is present in great excess, and even a small percentage of the above is enough to kill the reaction in its sensitive initiation stage. I have chacked that just 20% powdered Mg for the dehydration and initiation stages, rest turnings, works OK.

Its curious that the patent authors did not mention any of this, its almost like they wanted you to think the patent is rubbish. I do not want to blow my trumpet, but I think I explained more in a paragraph I published on the reaction than they did in their entire patent.

[Edited on 24-2-2011 by len1]
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[*] posted on 24-2-2011 at 08:46


Yes, I think that is a plausible explanation, considering in addition that pok used a mixture of turnings and powder. It also explains len1’s very early failure, IIRW…

Others have used miscellaneous powder grades with success (len1, nurdrage, woelen and me) without a narrow specification.

Peach: as you stated, 180 C is probably a real slow boat to China. What the hell kind of kerosene are you using that’s so low boiling??? Also why not measure gas evolution properly with a simple gazometer like len1 did and also me (but only towards the end of the reaction)?
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[*] posted on 24-2-2011 at 10:48


Results with kerosene, argon, magnesium from a sharpener, t-butanol and 24h of reflux


Method


I have used the same KOH and kerosene as before, and acquired the magnesium by drilling holes in a pencil sharpener with a 6mm drill bit.

The KOH and magnesium was weighed into 20ml of kerosene, the glassware setup and thoroughly rinsed out with argon. 1ml of t-butanol was then added to the funnel along with 5ml of kerosene, before more argon was added and the glassware sequentially closed up. The exit of the glassware is through an oil bubble.

This was brought straight to reflux and I noticed gas evolution in the oil bubbler. Slower than before, and fully stopping after 1 hour. I proceeded to add the alcohol over 30 minutes, using two 5 minute additions to split it in half.

Over three hours, the solution gradually turned a dull grey, and the magnesium itself. There was a building layer of white solid around the surface of the solution, which was well fixed in place regardless of the mantle temperature. I saw bubbles evolving at the trap approximately once every thirty seconds. After calculating the reaction could take up to 56h to complete at this temperature and rate of evolution, I decided to leave it as long as possible.

Approximately 11 hours after the refluxing starting, I returned and was unable to see any bubble in the trap over 3 or so minutes of watching it. The white solid had now blocked off the entrance to the funnel, and I had been concerned it would do the same with the remainder of the flask, but it seemed to have stopped growing directly under the condenser, so I felt confident leaving it to reflux overnight.

After 24h of reflux, I stopped heating. Whilst this is around half of the predicted time, there would still be enough potassium present for me to see it if it had functioned.

Once cooled, I emptied the flask out into a beaker and began looking for signs of potassium. I found none. On adding water, there was nothing abnormal.

I was able to remove the white solid with hydrochloric. And I found the material that had been blocking the addition funnel has, in part, 'melted', despite it now being removed from the glass.

Observations


I suspect the white solid I saw may have been KOH, perhaps bound up in oil somehow, as it would explain how it seemed to melt on exposure to the atmosphere.

I am in 100% agreement with Len that the percentage of magnesium you require to dry the KOH has to be finely divided for the solid / solid interaction to function. (***Len, you know what patents are like. They are not lying by forgetting to tell you that and they could easily argue it should be common knowledge, but they are preventing easy replication, 'theft', of the patent).

I strongly believe the slow evolution of gas I saw before adding the alcohol was directly related to the large size of my chips. On this point, notice how full the flask appears when the chips are larger.

I also agree, it is unlikely to be critical if the remaining magnesium is powdered or not, as the second stage is a liquid / solid reaction. It would likely function faster with a smaller particle size, but this also means using more expensive magnesium for the entire mass.

As a result, I am growing suspicious of the discussion of 'magnesium purity', and believe it is more to do with this first drying stage and ensuing the magnesium is not passivated before adding it (perhaps by freshly producing those chips or rinsing the magnesium with dilute hydrochloric before hand; this is used with amalgam methods, where the oxide on the aluminium is first removed with dilute NaOH / KOH and the aluminium is then rinsed to remove the alkali, immediately before adding the aluminium to the flask).

Judging by the gas evolution rate after my addition of alcohol, temperature is critical to getting it done in a few hours. I believe the gas I was seeing may have been due to water left in the KOH, and not from potassium formation.

Suggestions


Use a bubbler

This can be as simple as a length of tube going into a cup with some oil in it. Try not to fill the entire cup as the oil will be sucked back towards the glass if and when the temperature goes down inside it.

This will not only ensure your system is devoid of oxygen, you can now judge when and how fast gas is being evolved; which is an important factor.

For example, I suspect some of the failures may have been due to the magnesium particles sizes, mixing and preheating times.

Ideally, you should not add any of you alcohol until the initial bubbling has ceased, entirely.

For those wishing to be more adventurous, invert a test tube, burette or something similar over the oil trap. The gas evolution rate can be slow, and having a setup where you can put indicator marks on the collector will allow you to walk away and come back half an hour later and see how much extra has come out.

If you use a well graduated collection tube, you will also be able to determine the rough water content of the KOH, and possibly check this and make adjustments to the magnesium masses, as well as gauge how complete the reaction is. You will also be able to accurately determine the rates, which is useful for trying different solvent and alcohols later.

This is all useful, even the basic versions of it, as I strongly suspect people are adding their alcohol before the initial evolution is over, that this period is heavily influenced by the form of the materials you use, and that false results (like my own potentially false one for IPA) could come about because the reflux times are an order of magnitude incorrect.

Check your solvents BP

I really can't stress this enough. Don't even bother if you don't check it first.

As you will see further down, the same bottle of kerosene contains a wide span of BP's. This is an incredibly simple check to do, and means the difference between it taking 3 hours or 30+ based on seemingly small variations in BPs.

You will almost certainly need powdered magnesium

The rate of drying will increase as the particles get smaller, so one can not simply say, well it worked with xxx chips so it will work with others. I could see a substantial difference in evolution rate using chips from drill bits with just a few mm of difference in their diameter.

If you can't get very fine powdered, you can extend the initial drying period. Judging that mine appeared to stop bubbling through the oil around 11h after starting the reflux, you can expect it to take a long time. My experience took roughly an order of magnitude longer than Pok's.

Consider testing your unknown sources of solvent with bromine water

For the presence of double bonds.

Check you alcohol's BP and MP

I have discovered the sample of t-butanol I have, whilst melting and boiling around the correct regions, is showing more than 2C variation around them.

This suggests it also contains some of the other isomers, all of which have much higher BPs and much lower MPs. These are unlikely to quench the reaction, but it has been mentioned that they may not be stable and so not take part.

You may need to adjust the volume of alcohol used, or reflux times, based on this.

n-butanol
MP -90C
BP 118C

iso-butanol
MP -102C
BP 108C

sec-butanol / 2-butanol
MP -115C
BP 99C

t-butanol
MP 25C
BP 82C

A sample of t-butanol arrives. Note that is it is truely liquid, and the room is at 14C, 10C below t-butanol's melting point


I stick it in the freezer and a true solid forms, quickly (within minutes)


I try the fridge. It becomes a slush, which is turning back to a true liquid as fast I can take the photo


I'm going to redistill it



I begin collecting a slowly rising temperature at 81C. I collect around 5ml from here to 83 or 84C




The distillation ends at 91C, around ten above the BP of t-butanol


I have distilled around 9ml of the alcohol. There was no fractionation, implying whichever other isomers are in there are perhaps azeotroping with the t-butanol. But I suspect, due to the reasonably close BP and MP's, that it is primarily the t isomer


There is still something stuck in the flask from the first attempt, despite days of soaking in biological powder, rinses with KOH, sulphuric and hydrochloric. I have to wipe it out and rinse again


KOH


STAND UP FOR CHRIST'S SAKE! It's the Queen! A 2p for size comparison. These came from a 6mm drill bit.



Remember the original "You've got loads of magnesium in there! Where's it gone!?" arguments?


It's home, for the next day


Starting to warm it up


What I would guess to be around 3-6h later, given this camera has no time stamp, the white solid appearing around the top


You seriously want one of these


Many hours later, 24 of them to be exact


I don't see blobs, but I can't see much through all that muck anyway


Nil poi!


Distillation of Kerosene - Homefire Premium Paraffin, EEC code 294-779-5


I was thinking of trying this and was them spurred on by Eclectic.

I poured some kerosene alone out and distilled around 25ml of it. About two thirds of it came between 160 and 190C in a continuous band, with the majority being at 180 to 190C. I then decided to go and make a cup of coffee.

On returning, there was still a fair amount of material in the flask, around a third, but the temperature had plummeted and the distillation stopped. This was clearly some significantly different fraction.

I tried running the mantle all the way up to it's maximum, but had a hard to getting the remains to distill correctly. It was coming over a drop every minute or so, and it was barely making it through the column, let alone engulfing the thermometer correctly. As a result, I was getting temperatures like 130C, wrong, as the component moved past the thermometer without fully touching it.

I proceeded to try two loose layers of foil around the back of the column to encourage the material to fill it correctly. No luck!

In the end, I had to empty it out and use the thermometer in boiling flask method. Using a propane torch to heat boiling kerosene is not my cup of tea, so I was reluctant to cook it for more than need be.

It was obviously boiling and the temperature was reading around 220-230C. It may have gone ten degrees higher if I continued to heat for prolonged periods.

I'm not sure why I had such a hard time getting it through the distillation. I have distilled things at those temperatures many times before and been able to do it. I can only suspect it has something to do with enthalpy and the weight of the material.

This heavier fraction smells different to the bulk. It smells more like wax than the more etherial smell of the kerosene in the container.

Incidentally, I just remember, I forgot to check the density of this remaining fraction. Bastard! :D

Observations


This confirms the idea, there are certainly high boiling point components in there, and by tens of degrees more.

There also seems to be a usable amount of it in there, not traces.

Suggestions


If you have as much difficulty as I did getting the higher boilers through a still setup, or just can't be bothered to set it up in the first place (which is understandable), there is a very easy way to get them.

Fill a beaker or Erlenmeyer with your kerosene and heat it, open topped, OUTSIDE, in a sand bath, with a thermometer in the sand and it kept to around 200C. The lighter components will boil off and you'll be left with the higher ones you want.

As the higher boiling points in my example were a solid separate fraction, they are unlikely to go anywhere provided you keep the temperature at or below 200C, but you want it above 180 to 190C.

NurdRage warned against using candle wax due to the potassium ending up sealed in a solid wax lump. And the solid is difficult to remove from the glass anyway.

Someone else has suggested something I thought was a good proposition, to use candle wax and then dissolve it in a lighter fraction once done. Alternatively, remove the potassium whilst it is still molten, as Len did using a pipette to capture his sodium.

I am also curious to know what effect the alcohol is having on the BP of the solvent, but didn't feel up to checking that today. It's taken me about an hour to upload and tag all the photos for your science porn pleasure.



The lower boiling fraction


The higher, stuck in the flask


Awwww


The ghetto temperature check. Your thermometer needs to be off the glass


I expect that would have gone a little higher with more prolonged heating


This higher BP fraction is coloured, whereas the lower I would call colourless


My plan!


I now have the t-butanol and have found a possible higher BP solvent. But I don't see much point in me continuing with this without some powdered magnesium.




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[*] posted on 24-2-2011 at 11:21


Peach:

”Ideally, you should not add any of you alcohol until the initial bubbling has ceased, entirely.

Not true, IMHO. In my experiments I add the alcohol right from the start with equally good results. Nurdrage did the same (but claimed variable results). There’s nothing in the proposed reaction mechanism to suggest adding the alcohol early impedes anything. Believing you need to add it after dehydration now belongs to the realm of superstition as far as I’m concerned…
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[*] posted on 24-2-2011 at 11:46


I seem to recall heated debate with regards to repeats of that. :P

It may be that what you're seeing is a partial effect, and needs more constant conditions to check it.

I agree, it's not 100% positive that the dehydration needs to be fully complete for it to function, but I am (like NurdRage) suspicious at the lack of repeated results being used to confirm that it is false. If we look back to the beginning of the thread, that vast majority of the first ten pages or so is filled with people calling Pok a troll and a liar, because of the lack of repeats.

Quote:
Alkoxides, although generally not stable in protic solvents such as water, occur widely as intermediates in various reactions, including the Williamson ether synthesis.

Many metal alkoxides thermally decompose in the range ~100-300 °C

Metal alkoxides hydrolyse with water


[Edited on 24-2-2011 by peach]




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[*] posted on 24-2-2011 at 11:59


Im curious since it seems that alot of the issues concerning success here involves the initial drying of the KOH can anyone think of an alternative means of drying the KOH that would not interfere with the following reaction?

Im thinking something along the lines of azeotropic distillation but then you would have alot of Alkoxides present at the start of the reaction. This may not be such a bad thing but its tough to say since I really have no means of experimenting with this reaction.





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[*] posted on 24-2-2011 at 12:31


Peach:

Part of the heat (but not enough light!) in that ‘debate’ was due to Nurdrage’s almost point-blank refusal to take into account any theoretical considerations based on what is broadly accepted by most here as the most plausible reaction mechanism (a system of 4 more or less concurrent chemical reactions). Nurdrage claimed variability without ever proving this observed variability was significantly higher than natural variability. Nurdrage also early on dispensed with the silly routine of adding the alcohol in a carefully staged ceremony, with success. I just went one step further, as did he. The 4 reactions don’t occur in neat, sequential phases.

Alkoxides hydrolyse with water? PRECISELY, without (t-BuO)2Mg (for instance) hydrolysing (probably Grignard reagent style) there can be no catalyst recycling. Any early formed K t-BuO would be hydrolysed by early remaining water. So what? It goes back to KOH and t-BuO… WHERE’S the problem???

The patent authors almost certainly based their publication on very few successful experiments.

As regards: "It may be that what you're seeing is a partial effect, and needs more constant conditions to check it." is fuzzy gobbledigook with almost no real meaning.


Sedit:

Fusing the KOH in the absence of CO2 or H2O will dry it. Azeotropic dostillation should also be possible. The patent’s example on sodium doesn’t prescribe any drying of the NaOH. Of course NaOH is naturally drier than KOH but completely dry it ain’t.


[Edited on 24-2-2011 by blogfast25]
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[*] posted on 24-2-2011 at 13:34


I thought about fusing under N2 like you stated but then I realized that after fusing your going to need to break it back up and theres a good chance that while doing this your just going to add water from the air into it such as shown by peach that ground up KOH absorbs water rather quick. If the azeotropic distillation could work atlest one could dry it and then proceed with the reaction without ever removing the KOH from the container.

Im just musing really because it just seems to me that some sort of predrying could really help ensure things went as planned instead of having a variable amount of water causing you to not be sure if the Mg will be sufficient enough in drying it while still being able to react. Like you said about the possibility of Grignard style reacting if there is to much water present then its just not going to work. I believe it has been mentioned somewhere before in this thread but maybe some of the tricks used for Grignards could be employed here such as a small amount of Iodine or sonication.





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[*] posted on 24-2-2011 at 15:07


Well as a dehydrating agent maybe powdered magnalium 50:50 as it's very easy to break up? Also I ran across a tert alcohol that may work, and VERY easy to make from terpintine or limonene:
http://en.wikipedia.org/wiki/Terpineol
Terpin hydrate may work too, though I expect it will dehydrate to terpineol.
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[*] posted on 24-2-2011 at 20:59


Quote: Originally posted by len1  
The Mg I used in my first post up the thread, was what I have in the lab for Grignards. But I have since checked that the Mg from three years ago also works if powdered.
[Edited on 24-2-2011 by len1]


How did you powder it?
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[*] posted on 25-2-2011 at 07:51


Quote: Originally posted by Sedit  
Like you said about the possibility of Grignard style reacting if there is to much water present then its just not going to work. I believe it has been mentioned somewhere before in this thread but maybe some of the tricks used for Grignards could be employed here such as a small amount of Iodine or sonication.


You’ve misread. Quite a few pages above it’s explained that the catalyst recycling is basically:

Mg(OR)2 (sol) + 2 H2O (sol) === > Mg(OH)2 (s) + 2 ROH (sol)

… which is very reminiscent of how a Grignard reagent hydrolyses:

R’MgX (sol) + H2O (sol) === > (OH)MgX (s) + R’-H (sol)

The similarity is even more striking because both reactions take place in aprotic solvents with only very little water present.

In the case of K-synthesis with t-alcohol, a little water is NECESSARY to recycle the catalyst. The water is constantly being supplied by the initiation reaction:

KOH (s) + ROH (sol) === > KOR (sol) + H2O (sol)

Quote: Originally posted by Eclectic  
Also I ran across a tert alcohol that may work, and VERY easy to make from terpintine or limonene:
http://en.wikipedia.org/wiki/Terpineol
Terpin hydrate may work too, though I expect it will dehydrate to terpineol.


Terpineol mixtures could be excellent catalysts for this reaction, displaying possibly good reactivity, high solubility and low volatility. But something that requires CF3COOH to synth. it hardly constitutes ‘easy to make’ in my book! And I don’t know of any OTC sources that contain it in recoverable quantities, do you?


[Edited on 25-2-2011 by blogfast25]
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[*] posted on 25-2-2011 at 07:58


That's just if you start with limonene....Start with turpentine:

http://en.wikipedia.org/wiki/Alpha-Pinene
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[*] posted on 25-2-2011 at 08:48


Yes, starting from turpentine opens up quite a few possibilities to synth. terpinol. Finding pret-a-porter recipes may not be so easy, though. I’ll start with SM organic…
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[*] posted on 25-2-2011 at 09:18


Quote: Originally posted by blogfast25  
Yes, starting from turpentine opens up quite a few possibilities to synth. terpinol. Finding pret-a-porter recipes may not be so easy, though. I’ll start with SM organic…


Simple hydration with an acid catalyst should do it, there is a big skeletal rearrangement and out it pops!

http://en.wikipedia.org/wiki/Alpha-pinene
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[*] posted on 25-2-2011 at 09:29


Well, I was thinking that too but I've found no info on how to convert the hydrate (a saturated hydrated diol) to actual terpineol. Another route is pinene (turps) + glacial acetic acid = terpineol acetate. De-esterify with hot NaOH to get the alcohol. Very feasible, I believe...

Surprisingly not a peep on SM organics about this assumed simple synthesis...




[Edited on 25-2-2011 by blogfast25]
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[*] posted on 25-2-2011 at 09:35


I have done the reaction with iodine to make the 4- methyl isopropyl benzene and it was fast and exothermic.
Sulphuric acid and ethanol gives a mixture of terpineol and terpineol ethyl ether.
I think you could get terpineol under the right conditions.

Here is an example;

http://pubs.acs.org/doi/abs/10.1021/jf010341b

[Edited on 25-2-2011 by ScienceSquirrel]
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[*] posted on 25-2-2011 at 09:52


Quote: Originally posted by ScienceSquirrel  
I have done the reaction with iodine to make the 4- methyl isopropyl benzene and it was fast and exothermic.
Sulphuric acid and ethanol gives a mixture of terpineol and terpineol ethyl ether.
I think you could get terpineol under the right conditions.

Here is an example;

http://pubs.acs.org/doi/abs/10.1021/jf010341b

[Edited on 25-2-2011 by ScienceSquirrel]


For 4- methyl isopropyl benzene, was the starting product actual turpentine?

As regards the article, I'd have to buy it to get the conditions right, including details on work up.
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[*] posted on 25-2-2011 at 09:57


Yes it is.
Mixing real artists turpentine with iodine results in huge amounts of hydrogen iodide gas and pretty much technical 4-isopropyl methyl benzene.
A quick distillation and it is pretty much pure by NMR.
Ask nicely in references for the article, I am sure someone will oblige :)
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[*] posted on 25-2-2011 at 10:04


I'm very interested in this terpineol synthesis from turpentine. t-Butanol is proving difficult to find. I saw one post earlier about a source, but that was UK only (I'm in the US). So I'm interested in these alternative preparations. I'm eager to hear more information, especially since I have little experience with organic chemistry!
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