naf
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Diethyl ether simple distillation
Hi Guys, first post!
Im making some diethyl ether for an extraction, and figured I would just perform a distillation of some starting fluid.
Ether is pretty nasty shit, and I really want to keep it away from any sort of heat source. would it be possible to just apply vacuum to the ether
using one of those cheap hand-powered vacuums (often sold to bleed automotive brakes) and bubble through some salty icewater, like this: 
Then just split the layers?
At RT ether should boil at around .5 atm, and at 0C ether boils around .25 atm, so as long as I keep the vacuum between those two levels, I shouldn't
have a problem with ether vapor getting in the vacuum, right? I suppose though, that it depends largely on the concentration of ether in the starting
fluid and the bp/vapor pressure of the other substituents.
Im worried that the ether vapor would just leak out the vacuum pump, possibly dissolve some internal parts (its pretty cheap plastic and rubber), and
worst case scenario combust under the compression "stroke" of the vacuum pump.
If this works, though, it seems significantly safer and better than production using sulfuric acid and ethanol or distillation of starter fluid
through heat.
Thoughts?
[Edited on 7-12-2011 by naf]
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hissingnoise
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IIRC, besides ether, other constituents of starter-fluid are quite volatile and to effect even a halfway good separation you'd need a very large
fractionating column with a receiver well below 0°C!
I sure hope, for your sake you're not thinking of inhaling dangerously carcinogenic impure ether!
And it should be noted that not all starter-fluids contain ether!
What you're thinking of doing could well end in fireballs and tears . . .
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zoombafu
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Here is a pretty good video on youtube
http://www.youtube.com/watch?v=ytdO3YzXNkQ
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naf
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I have little to no interest in inhaling ether.
according to my bottle of starter fluid, (super tech, wal-mart brand), it contains 'ethyl ether, upper cylinder lubricant.' as far as my knowledge of
most lubricants goes they typically consist of a variety of long hydrocarbon chains with fairly high boiling points, minimizing the contamination in
the final product. give the distillate a few washes with water to ensure any volatile contaminants that came over are not water soluble, and then we
shouldn't have an issue with the ether contaminating the aqueous phase in an extraction, right?
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bbartlog
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Ether is so volatile that distilling it under vacuum seems like it makes the condensation require needlessly low temperatures. In the setup you
propose, I think that the vapor pressure of ether atop the icewater would be high enough that you would lose a significant amount of it. Why not just
dispense with the vacuum part and gently heat the starter fluid canister (say, by putting it in some warm water)?
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waLLcandy
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From wiki, the composition of most starting fluid is a mixture of <60% diethyl ether and some mixture of hexane and heptane. These are all very
volatile, and will all likely get sucked out by a mild vacuum. When the pressure goes down, things only get more volatile--thus just like hissing
noise and bbartlog said, you'd have to go much, much, colder than ice water to condense it.
| Quote: |
give the distillate a few washes with water to ensure any volatile contaminants that came over are not water soluble, and then we shouldn't have an
issue with the ether contaminating the aqueous phase in an extraction, right? |
Okay, so going back to the composition of starting fluid--the amount of aqueous contaminants is incredibly low (if any?) Washing your ether with water
would remove them, but it's unlikely you'd even have any from vacuuming because any aqueous contaminants are much more likely to have much higher
boiling points. The real concern is the heptane and hexane. I, myself don't know of a safe, at-home method of separating these. Someone mentioned
carcinogens, but ether in the absense of stabilizers easily forms explosive peroxides that can build up in the joints of your glassware or in the
threads of your storage container. (So you could lose your fingers, but luckily they'd grow back as a mangled cancerous mass.  ) Distillation is tricky. It's considered unwise to heat ether over 40C for the same
reasons.
I'd suggest, if you're inexperienced with handling chemicals, reactivity and safety, don't try this as a first in-home experiment.You mentioned
earlier that you wanted to extract something--perhaps there's a different solvent other than diethyl ether you could try in the meantime?
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naf
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i do have some experience with flammable chemicals. I'm a college student and have taken genchem I and II and organic chemistry I, all three of which
included 3 hours a week in the lab, usually working with one type of solvent or another.
I've toyed with the idea of using other solvents, but to start with I cant find much solubility data on it, and don't have any excess pure solute to
perform solubility testing.
so heres a novel idea, thought of it earlier today.
So the main constituents of starter fluid are hexane, heptane, and diethyl ether eh? well because of that lovely oxygen right in the middle of ether,
it does have some solubility in water. Hexane and heptane, however, because of the lack of virtually any polarity or H+ acceptors/donors, have a
solubility in water roughly 1/100th that of ether, so basically no solubility in water. While our yield will be pretty low, why not give the starter
fluid a ton of extractions with a lot of dH2O, then salt the hell out of the extractions and throw it in the freezer for awhile (don't freeze it
though). some of, if not most of the ether should come out of solution, if im not mistaken, and should be virtually hexane and heptane free! no heat
or vacuum required.
while the yield will be low, i really only need 5 mL (10 to be on the safe side) for this extraction. Yield should be far above that, and the purity
would be unmatched compared to a distillation.
if im not mistaken, slightly acidifying the dh2o while extracting the starter fluid and slightly basifying the ether/h2o mix while separating the two
should help with yields, right?
yes, i realize how much water you'd need for this.
[Edited on 9-12-2011 by naf]
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BromicAcid
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| Quote: | if im not mistaken, slightly acidifying the dh2o while extracting the starter fluid and slightly basifying the ether/h2o mix while separating the two
should help with yields, right?
yes, i realize how much water you'd need for this. |
dH<sub>2</sub>O? You mean distilled water? I was reading it as if you were trying to use deuterated water for the first bit. If you
mean distilled water that's a gimmie around here. How much water do you think you need for this? Solubility of diethyl ether in water is actually
one of the reasons it's not the best for aqueous extractions, Wiki gives 69 g/L which is pretty high, especially if you are only trying to get 10 mL
or so. What you propose might well work.
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naf
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not really sure what the d stands for actually, was thinking di-ionized h2o actually, but i guess its pretty much the same thing. i know its one of
the two. i've just seen it before in literature.
figure id throw a little vinegar in the initial extraction then basify it with some sodium bicarbonate. keep it USP.
Ether solubility: 9.6 mL / 100 mL h2o
assuming we get ~300mL starting fluid, at 40% thatll give us 120mL ether in a can.
lets say we do two 30mL washes with dH2O to get rid of any cancer-causing water-soluble impurities, then three 400mL extractions. sounds like a good
starting point to me.
Under ideal circumstances, ill get about 100mL ether. can't find any data on the solubility of ether in cold brine, so realistically, im happy with
50mL. 50% yield isn't bad considering the safety and cost of this method compared to others.
Ill likely discard excess ether once I'm done with the extraction, but maybe if i get adventurous ill dry it over some magnesium sulfate and throw in
some solid KOH and store it.
[Edited on 9-12-2011 by naf]
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waLLcandy
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Diethyl ether is at best a very weak base. I really doubt that vinegar will help much in an extraction, but sure give it a try. The pKa of the
conjugate acid is -3.5, so assuming you got that, adding bicarbonate would get you back your organic ether..............................
After that, you planned to wash out "aqueous cancer-causing impurities" with water. (Where did you see any mention of aqueous carcinogens in starter
fluid anyway?) Then use the very slighty soluble nature of ether in water to extract it from the hexanes. This last part has some hope. If you use a
ton of water you might be able to separate some ether from the hexanes. I would abandon the acid/base extraction and just do that. But then you have
the issue of large barrels of ether water. Here you could use very gentle heating (or vacuum) and a condenser to carefully distill it off.
FYI, if you use brine, you'll only force the little bit of ether out of the aqueous layer. (i.e. diethyl ether is less soluble in saturated sodium
chloride solution).
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Endimion17
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There's no way this could work. Ether is so volatile it would require extreme cooling.
Additionally, using a vacuum pump would cause fire (if the pump is electrical) or build up lots of explosive fumes in the sewers (regular water pump).
Just distill it over a water bath and cool it with ice cold water. Don't forget to stop the distillation before everything evaporates, because ether
often contains peroxides and you don't want to let that dry off.
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Panache
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Why not? Once used as an alcohol substitute during prohibition, medical students were famous for their ether parties.
It doesn't have the title of 'king of inhalants' for nothing i imagine.
Just use hot water out of the tap for your heat source, you're complicating things with the vacuum.
i like your drawing, i don't think you could make it crapper, however its communicating perfectly clear.
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Bot0nist
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Yuk, It always left me with a sweet, sickly feeling. Not from starting fluid though. Dehydration of ethanol.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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naf
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I've given up on the distillation and dont have the money to invest in glassware for the dehydration of ethanol.
what do you all think about the water extraction I posted?
extract the ether from the starter fluid using copious amounts of distilled water (solubility: 9.6mL / 100mL), separating the leftover starter fluid,
then salting the hell out of the ether-water to force the ether out of solution. Perhaps using table salt or better yet epsom salt. Thoughts?
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Panache
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Extract into thirty degree tap water, then warm this further, either by adding boiling water or with anything that doesn't generate a flame, running
the boiling ether into the bottom of a bucket containing some ice. Use polypipe, its polyethylene and is impervisious to ether. Seperate then dry.
[Edited on 13-12-2011 by Panache]
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Coronzom
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What about dry ice?
The freezing point of ether is around -117 C. Heptane freezes around -90 C and Hexane freezes around -95 C.
If you add dry ice to ether you get a liquid temperature of -100 C which freezes everything but the ether. Decant the ether to completely remove the
other additives.
I'm not sure if this will work as you are adding the dry ice to a mixture and not the pure ether but has anyone tried this or knows anything about
this? Dry Ice is very cheap and easy to obtain where I live so I'll probably try it but if someone else has tried it, I'd like to know what the
results were.
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Rattata2
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I don't think dry ice will get it down to -100C.
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Coronzom
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If the ether was pure it would. My question is what temperature would the solution drop down to if mixed with the other additives.
Here are a couple of interesting resources I found to support my hypothesis.
https://www2.bc.edu/~hoveyda/cool.html
http://macro.lsu.edu/HowTo/solvents/Freezing%20Point.htm
I'm distilling what I have right now using a 200mm vigreux column and 500mm graham condenser slowly at around h2o boiling point. I plan on using the
dry ice on both the solution collected and the leftover solution to see what happens. My theoretical ether yield should be between 195 and 293 ml if I
can manage to extract it all. I'm expecting heptane contamination on the first distillation but it should be minimal so the dry ice should work there
no problem but I can't find the temperature of dry ice in heptane so the leftover solvent may or may not work the same way.
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Coronzom
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To be clear, I am doing this out of curiosity and not for any nefarious purpose. I am fully aware of ether production from sulfuric acid and ethanol
and I can get 750ml of 96% rectified spirits for $14 a bottle after tax so it is cheaper and easier to make ether from scratch. I am exploring this
alternate way to understand different ways to extract and purify various chemicals that are difficult to separate.
An example of this was isolating and purifying every chemical in a zinc carbon battery. It was more costly than just buying each of the materials
outright but I didn't do it for the chemicals. Combining two or more components to make something new is interesting and fun but I find greater
satisfaction separating mixtures.
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