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Author: Subject: Diethyl Ether - Illustrated Practical Guide
entropy51
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[*] posted on 26-12-2009 at 11:55


Quote:
the last bottle of ether I used claimed ethanol as a stabilizer
Tim, are you sure that wasn't CHCl3? EtOH is added to CHCl3 to prevent formation of COCl2 on storage, but I can't recall hearing that it would prevent peroxide formation in Et2O. But Cu was for sure used as a coating on the inside of ether cans to prevent peroxides.

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[*] posted on 26-12-2009 at 13:21


Sigma Aldrich claims 2% EtOH and 10ppm BHT in the first ether found on Google. BHT of course is better known for peroxide protection.

As I recall, the bottles were simply aluminum. I don't remember a coppery coating, and I don't remember copper pellets rattling around in the bottom (although I can't say I ever shook the stuff on purpose!).

I don't remember what was in the CHCl3, although I think we used CDCl3 more often, and being for NMR purposes, I don't think it had EtOH.

Tim

[Edited on 12-26-2009 by 12AX7]




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[*] posted on 26-12-2009 at 13:25


Aluminium bottles are the standard packaging aside from amber glass winchesters. I wouldnt expect there to be a copper coat, as this was purely my suggestion, and not something I had heard of previously.
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[*] posted on 1-1-2010 at 22:48


Quote: Originally posted by DJF90  
I'm not sure why hygroscopic liquids were stored over copper aonomus; the function of the copper with ether is to inhibit the formation of the peroxide.

Tim: I think the role of the copper is to actually catalyse the decomposition of any peroxide that may form. Definately a good thing. I had a paper on it somewhere but cannot find it. I'm familiar with ethanol being used to stabilise chloroform but its use in ether is new to me. Thanks for sharing!


Not to get off topic, but I recall it was both hygroscopic, and a larynchamator (sp). Something with 1,3-bromo-chloro _____ comes to mind. I don't think it had any peroxide forming ability, perhaps it had another function.

I think also, prior to making ether, it would be a good idea to make some peroxide test strips. You can make them by taking a KI/starch solution and soaking filter paper, followed by careful drying. Once you have the strips cut up, store them away from moisture.

To test, dip the strip in the solution/solvent, and wait for any reaction. A small amount of water may be required to initiate the reaction (atmospheric moisture, or maybe a drop of water). Blue indicates peroxide, light yellow coloration indicates some peroxides (enough to form some iodine, not enough to form the blue starch-iodine complex).

Though, if you have access to commercial suppliers, buying real test strips may be worth it. Why risk your safety on potentially dodgy test strips?
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[*] posted on 10-5-2010 at 22:25


Well I ran this reaction a couple of weekends ago with minor modifications. The most important of these was the use of a peristaltic pump to deliver feed ethanol via a capillary (broken thermometer).

The result of this arrangement was a greatly reduced incidence in bump and foam, with the very small droplets hardly disturbing the mixture in the first half hour and virtually no bump at all after the reaction settled down.

From my final yields there was also a slight reduction in the rate of ethanol coming over unreacted in the distillate.

I don’t have Len’s capability to definitively characterise my final product. But the whole of the distillate came over as a very tight fraction 34.5-35C after sitting overnight over CaCl2.

I would like to thank Len for his detailed posting and a bit of inspiration that not everything needs be done according to Vogels! One can actually experiment and look for improvements and adaptions to amateur settings.

I seem to be having problems inserting images so here are links to a couple of photos I took as an afterthought. Please don’t laugh at my current ‘lab‘. I have to fight with the wife as to when I can book the laundry.

photo 1

photo 2






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[*] posted on 10-5-2010 at 23:58


Two condensers? Ritzy. The bomex, not so much.



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[*] posted on 11-5-2010 at 07:45


Weird distillate?

That made already one month that I make a good amount of diethyl ether (2 L). This part of the the distillate is not a mystery, I purified and it is now store at -30 C. But in the bottom of the flask they were and other layer after the first distillation (the reaction distillation)??? That was the first time that I was seeing that. That was also the first time I was using ethanol without water (and a really small amount of isopropanol). Have you any idea of what this layer is made of? If it were isopropyl ether, will it mix with the ethyl ether/water/ethanol layer?
The ethanol use was Ethanol Bio Fuel for ethanol fire place.

I don't have made a lot of tests on this layer, but I have over 300ml of it, so it will be enough to find what it consite of.
I thing the first thing to do is to dry this layer and make a fractional distillation. With the boilling point and the density of each fraction I have good chance to find what it is.
The only test that I have already made is a flame test. This layer is very flammable (less that diethyl ether) and burn with a green flamme.

Hope you can help
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[*] posted on 11-5-2010 at 08:08


Di-ethylether: I did this as a kid: Just plainly distilling conc. H2SO4 with C2H5OH ...; no big deal ...
==> cooling with a NaCl-ice-mixture ...
==> ... and I believe the recommended procedure was to add also some water-free Na2SO4 into the boiling-flask for extra-dehydration ...
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[*] posted on 11-5-2010 at 08:12


Engager, to my mind soviet ring stands are the best.
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[*] posted on 29-10-2010 at 14:40


This is a great cheap and safe alternative to distilling from cans of startup fluid. Awesome writeup and pics in this thread. Thanks everyone :)

Regarding the distillation of starting fluid:

A few guys have posted their ideas. I've found it best to flip the can upside down and depress the spray tip which removes all of the propellant. The can will get nice and cold as the propellant leaves which will make the ether less volatile. Then use a manual (not electric) can opener to remove the bottom of the can. The cold ether can then be easily poured into your flask. Using a drill seems like a fire hazard : / [ friction -> heat -> fire + electricity -> sparks -> fire ] This way you get ether without it being vaporized into a difficult to control explosive aerosol.
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[*] posted on 16-3-2012 at 14:36


I have been repeating the work in the thread so far, using len's measurements.

I was curious if the work up could be improved to yield more d.ether by instead proceeding to redistil the crude yield immediately after the first distillation (without washing); to reduce the quantity of ethanol / methanol present without loosing ether to washing. Another interest was whether or not the by-products could be recycled back into the process (by avoiding neutralisation and dilution).

I took 25ml aliquots from the crude material, which roughly equated to 145ml of volume.

These were then redistilled and the temperature curves are in the graph below.

YELLOW:

This was done with simple distillation. The line is a continuous progression and features no separation. Not much good to be had there.

ORANGE:

This was with a vigreux column in the way. There are now two distinct plateaus representing the ethereal and alcohol regions.

BLUE:

The transition between the two is important as, ideally, it should be a vertical rise with a temperature drop before it, to show that clean fractioning is occurring. This slight dip is present, but it would be nice if the gradient was even steeper.

I was curious as to why the temperature wasn't rising within a minute or three, instead taking ten or so.

I then realised that ether, methanol and ethanol all form an azeotrope with water and proceeded to dry a 25ml aliquot of the crude ether; electing to use magnesium sulphate (as calcium chloride is incompatible as a drying agent with the alcohols present).

After drying, my volume of crude ether had dropped to just 9ml. Partly due to moisture absorption, but also due to the mechanical losses. I recovered about another 10 by squeezing the filter paper out. Messy.

I redistilled the now dry(er) crude ether through a virgeux and obtained this line. Which still shows two plateaus, but it is, if anything, a softer gradient than the untouched crude ether. Also note the lack of a dip before the climb.

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


It appears vigreux distillation of the untouched crude ether is the best of the three, and also easier than bothering to dry it.

Why there is a ten minute transition time (with material flowing through the still) I am not entirely sure. But it may be related to this having been done from methylated spirits; there is likely a complex blend of petroleum distillate, ethanol, methanol, dissolved dimethyl ether, diethyl ether, sulphur dioxide, sulphuric and water in the crude material. Starting from drinkable, ala white bunny, could provide an interesting comparison; if it is byproducts from the reaction it's self or the poisoned alcohol Len and I have used.

However, separation can be achieved with a vigreux and would likely be even better with a packed column.

Unfortunately, despite returning my results to the original crude ether, over the coarse of running all these mini experiments, I can see the level in the flask has dropped by what I later determined to be around 50ml. It is likely this is primarily ether that has evaporated off.

I now have around 92 / 93ml of crude material. I distil this, as is, through the virgeux and cut off at 73C.

The results can be seen in the second photo, around 42 / 43ml of aqueous still bottoms, likely full of water, ethanol and they are strongly acidic. This would suggest I have around 45ml of ether in that 100ml funnel in the photo.

I tried washing the ethereal result with 3ml of water and noticed no cloudiness. I split the aqueous off and checked it's pH. Right down around 1.

12g of sodium carbonate were then dissolved in 100ml of water and I begin adding a few mls at a time, shaking and testing. It is reading neutral after 7mls have been added.





I also noticed this. Which is the crude ether immediately before I distilled it all. Upon adding it to a flask with a bit of muck (tar) on it's neck (via a pipette), it split.

Perhaps it'd be more efficient to extract the ether or load the organic phase with something none polar rather than trying to remove the aqueous layer?



I'd have liked to make this more conclusive, but realised I couldn't offer a direct comparison against Len's numbers when the volume in the crude flask had dropped so noticeably.




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smile.gif posted on 17-3-2012 at 19:33


Nice work you've done here.
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[*] posted on 28-7-2012 at 18:26


Hey guys I just did this synthesis to the letter of Len's original procedure and re-distilled the washed ether with a vigreux column. I used Home Depot brand Denatured alcohol and hardware store grade sulfuric acid. Upon the second distillation I collected a very small yield of productcollected from room temperature to 70 degrees C. However upon adding anhydrous magnesium sulfate to the distillate in an effort to dry it further it began to boil even though its temperature was only 10 degrees. At this point I realized that clearly my reaction had been contaminated with something. I proceeded to let it boil believing that since the temperature was 10 degrees the ether loss would be minimal. It is still boiling right now. My question is what do you believe is causing this boiling at below room temperature? I am not sure the percentage break down of the denatured alcohol I am using which I know is where the problem is coming from. Do you believe that my product could be mostly methyl ethyl ether which has a BP of 7.4 degrees C? Any advice you have would be much appreciated.
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[*] posted on 29-7-2012 at 12:18


Check the MSDS for "Klean-Strip" denatured alcohol. I contains 50-55% methanol.
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[*] posted on 29-7-2012 at 17:52


Hah, I had that exact thing happen a couple years ago... "how the hell is my ether boiling below room temp???"

Very confusing at first... Eventually traced it to the Klean-Strip. I'd don't even get how they can get away with calling that "denatured alcohol."




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[*] posted on 30-7-2012 at 16:12


The "green" Klean-Strip alcohol is more than 90% ethanol and may be worth trying if you don't want to go to the expense of starting from 190 proof grain alcohol.



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[*] posted on 12-3-2013 at 10:45


I couldn't find anyone using a Vigreux or Hempel column during the reaction. Would this not hugely reduce water and ethanol contamination, recycling the ethanol back? Then subsequent washing would be much easier.
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[*] posted on 15-3-2013 at 18:01


Quote: Originally posted by GammaFunction  
I couldn't find anyone using a Vigreux or Hempel column during the reaction. Would this not hugely reduce water and ethanol contamination, recycling the ethanol back? Then subsequent washing would be much easier.


I have done this synthesis many times and I never had a lot of unreacted ethanol in my recovery flask. You also want to remove the water from de reaction flask because you want to keep your sulfuric acid over 70%.
Washing the product of this reaction is really easy, so there is no point to keep the water and the ethanol away from it.

[Edited on 16-3-2013 by Bikemaster]
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[*] posted on 28-3-2013 at 11:12


So i tried to make ether too . But the luquid that i get was not smell like ether.
So here is how i did
I used %98 , 40 gram of sulfiric acid and 60 gram ethanol. Fırst i cool them up and then i pour the sulfiric acid drop by drop.
than i pour the mixture to a baloon flask and put a reflux condenser on it. On the top of the condenser i attached a narrow-mouthed U pipe . The other side of the pipe is
connected to a another empty flask.
I heated up at 140 degrees. The volatile ether colelcted in the flask that connected to pipe.
I though it was ether . It should be ... i looked for its boiling point and it was near 36 C degrees. It doesnt disolve in water either. But its had very pungent odor.
Not even near to ethers'sweet sugared smell.

What the hell is this ??? Some oxidated product or what ?
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[*] posted on 10-7-2013 at 00:38


So I performed this synthesis today (I'm not 100% done yet), and I'd like to share an observation I made. To begin with, I was using anhydrous (distilled over CaO), EtOH (originally Diggers brand methylated spirits). During this time, the reaction mixture didn't turn black at all in the way Len1's did. It was slightly discoloured at best. When I ran out of anhydrous EtOH, I switched to straight, unpurified Diggers brand Methylated spirits (95% EtOH), within 20 minutes the mixture was pitch black. I'm assuming this means that the black colour is due to side-reactions not with the EtOH itself, but with the denaturent used in the methylated spirits.
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[*] posted on 10-7-2013 at 17:28


Quote: Originally posted by Myeou  
So i tried to make ether too . But the luquid that i get was not smell like ether.
So here is how i did
I used %98 , 40 gram of sulfiric acid and 60 gram ethanol. Fırst i cool them up and then i pour the sulfiric acid drop by drop.
than i pour the mixture to a baloon flask and put a reflux condenser on it. On the top of the condenser i attached a narrow-mouthed U pipe . The other side of the pipe is
connected to a another empty flask.
I heated up at 140 degrees. The volatile ether colelcted in the flask that connected to pipe.
I though it was ether . It should be ... i looked for its boiling point and it was near 36 C degrees. It doesnt disolve in water either. But its had very pungent odor.
Not even near to ethers'sweet sugared smell.

What the hell is this ??? Some oxidated product or what ?


Impurities masking the smell.

Check ph, neutralize with bicarb in water (brine), separate and redistill for dentists delight....

/ORG




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[*] posted on 22-7-2013 at 06:07


Quote: Originally posted by skeletal-clown  
So I performed this synthesis today (I'm not 100% done yet), and I'd like to share an observation I made. To begin with, I was using anhydrous (distilled over CaO), EtOH (originally Diggers brand methylated spirits). During this time, the reaction mixture didn't turn black at all in the way Len1's did. It was slightly discoloured at best. When I ran out of anhydrous EtOH, I switched to straight, unpurified Diggers brand Methylated spirits (95% EtOH), within 20 minutes the mixture was pitch black. I'm assuming this means that the black colour is due to side-reactions not with the EtOH itself, but with the denaturent used in the methylated spirits.


I could be way off here, but I've ran this synth many times and always attributed the color change to using sand. It appears from the photos that grains of sand can be seen at the top of the flask.

Maybe it is a side reaction that would occur without the sand. I would not know, cause I've always used sand as a buffer. Clean sand or silica.

I know it has nothing to do with methylation, cause I've always used grain alcohol.
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[*] posted on 22-7-2013 at 07:49


Quote: Originally posted by Organikum  
Quote: Originally posted by Myeou  
So i tried to make ether too . But the luquid that i get was not smell like ether.
So here is how i did
I used %98 , 40 gram of sulfiric acid and 60 gram ethanol. Fırst i cool them up and then i pour the sulfiric acid drop by drop.
than i pour the mixture to a baloon flask and put a reflux condenser on it. On the top of the condenser i attached a narrow-mouthed U pipe . The other side of the pipe is
connected to a another empty flask.
I heated up at 140 degrees. The volatile ether colelcted in the flask that connected to pipe.
I though it was ether . It should be ... i looked for its boiling point and it was near 36 C degrees. It doesnt disolve in water either. But its had very pungent odor.
Not even near to ethers'sweet sugared smell.

What the hell is this ??? Some oxidated product or what ?


Impurities masking the smell.

Check ph, neutralize with bicarb in water (brine), separate and redistill for dentists delight....

/ORG



So, let me get this straight. In various reactions, usually ones including an acid, as in this case H2SO4, there is acid left in the finished product.

If the final product is acidic, that would mean that some H2SO4 and water is still hanging around. As to my understanding, pure ether as with most solvents can not have a PH.

Knowing this, I assume the brine is being used to neutralize the left over acid. It wouldn't be necessary to be particular on how much brine is added, as it will be separated off.
In other words there is little chance of the ether becoming too basic afterwards.

I've always read this procedure being employed to remove left over acid.
I've never seen a procedure employing the addition of acid to bring back to neutral, but that may be due to my lack of experience.

As with everything I do in life, I over examine to the extreme.
I just like to clarify for myself and others.

BTW, if NaHCO3 and H2O is considered brine, then what is NaCl and H2O? I always thought NaCl and H2O was considered brine. They may both be considered such.
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[*] posted on 22-7-2013 at 09:34


<strong>Organikum</strong> had a brain fart. NaHCO<sub>3</sub>(aq) is used to neutralize the remaining acid. Saturated aqueous sodium chloride, sat. NaCl(aq) aka <em>brine</em>, and is used for initial removal of water before employing better drying agents.

[edit] Outside of chemistry, 'brine' is any old aqueous solution of salt(s), e.g. seawater. In chemistry, it's generally taken to mean sat. NaCl(aq).

[Edited on 7/22/13 by bfesser]




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[*] posted on 22-7-2013 at 23:53


Quote:

I could be way off here, but I've ran this synth many times and always attributed the color change to using sand. It appears from the photos that grains of sand can be seen at the top of the flask.

Maybe it is a side reaction that would occur without the sand. I would not know, cause I've always used sand as a buffer. Clean sand or silica.

I know it has nothing to do with methylation, cause I've always used grain alcohol.


Hmm, this is interesting. I also used sand in my synthesis, and didn't even bother properly cleaning it. (Coarse builders sand heated multiple times in a sand bath to destroy most organics).

You're certainly right about it not being methylation, MeOH has been banned in denatured alcohol in Australia for over 10 years. I couldn't find anything about the denaturant used now on the product's MSDS, but I assume it must have been removed via distillation over Calcium Oxide (My method of drying EtOH).


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