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khourygeo77
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How to separate ethanol from essential oils dissolved inside (not so easy)
I tried a few methods. I added salt water to try and separate to no avail, and then tried to fraction distillate, but it seems like the essential oils
will stick to the ethanol no matter what
The only way that has worked in separating the 2 is by leaving the mixture on atmospheric temperature, in which the oil would fall to the bottom and
the alcohol evaporate. If I heat the mixture to around 40 deg C, the oil will vaporize with the alcohol. Any help?
Thanks a lot
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2-1-2017 at 14:27 |
alking
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If the oil separates from the alcohol into two layers why not just separate it that way? Have you tried vacuum distillation? If you're just trying to
dry it and not recover the alcohol you could use a drying agent as well, store it over some CaCl2 or something that will absorb alcohol.
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PirateDocBrown
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Why is there ethanol in your essential oil to begin with?
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khourygeo77
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Quote: Originally posted by alking  | | If the oil separates from the alcohol into two layers why not just separate it that way? Have you tried vacuum distillation? If you're just trying to
dry it and not recover the alcohol you could use a drying agent as well, store it over some CaCl2 or something that will absorb alcohol.
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The oil doesnt separate from the alcohol. And the essential oil normally sticks to salts very easily, so I'm not sure the CaCl2 gonna work.
I havent tried vacuum distillation as I dont have the required equipment. What chances are there to separate it using this method instead of the
common pressure one?
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khourygeo77
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I extract the essential oil with ethanol.
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JJay
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There are a number of things you might try....
I don't really know what your essential oil is, so I can't really say, but if the essential oil is an acid, forming an alkali salt will likely greatly
reduce its solubility in less polar solvents. If the sodium salt doesn't precipitate out of the ethanol on its own, you could try chasing it out with
ether or perhaps brine.
If the essential oil is an aldehyde or methyl ketone, you can likely form the bisulfite adduct to decrease solubility.
It might be possible to freeze the essential oil.
Vacuum distillation might work. You probably don't want to try using massive quantities of 4A molecular seives.
You might try adding a substance that forms an azeotrope with ethanol or a substance that forms an azeotrope with the essential oil.
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Sulaiman
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OOPS !
sorry to mess up the thread,
as an afterthought I deleted it because I thought it would make me look dumb, but you quoted me too quickly 
I admit it ... I did suggest water
CAUTION : Hobby Chemist, not Professional or even Amateur
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khourygeo77
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| Quote: Originally posted by JJay | There are a number of things you might try....
I don't really know what your essential oil is, so I can't really say, but if the essential oil is an acid, forming an alkali salt will likely greatly
reduce its solubility in less polar solvents. If the sodium salt doesn't precipitate out of the ethanol on its own, you could try chasing it out with
ether or perhaps brine.
If the essential oil is an aldehyde or methyl ketone, you can likely form the bisulfite adduct to decrease solubility.
It might be possible to freeze the essential oil.
Vacuum distillation might work. You probably don't want to try using massive quantities of 4A molecular seives.
You might try adding a substance that forms an azeotrope with ethanol or a substance that forms an azeotrope with the essential oil.
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Thanks for the detailed help.
I tried to precipitate it with brine and even alkalis like potassium carbonates. It doesnt work, the essential oil will stay with the alcohol and
distill with it. Water makes things worse. It is more difficult to separate the oils from the water most of the times as they mix with it and give it
white color and cannot be easily separated too. Freezing essential oil is impossible
By ether, you mean try it with diethyl ether? Is it miscible with alcohol?
Didnt understand what you mean about vaccum distillation
I was thinking about adding something to do just this: Form azeotrope with alcohol. I'm not looking at forming one with essential oil, because there
are so many different ones, would be more simple to look for one that forms azeotrope with the known product (alcohol). I have tried to add NH3
dissolved in water to the alcoholic mixture a few days ago, it successfully formed an azeotrope but not sure how effective it was as i couldnt
continue the experiment to find out if the essential oil would stay at the bottom or go up with the azeotrope. There is this annoying thing about the
essential oil. If it is mixed with either water or alcohol it is hardly separable. It also takes a much lower temperature to get the oils with alcohol
than with water. It seems that the vapors of the substance are the ones that bring the oil to a solubility, and not the solvent itself in watery form
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khourygeo77
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| Quote: Originally posted by Sulaiman | sorry to mess up the thread,
as an afterthought I deleted it because I thought it would make me look dumb, but you quoted me too quickly
I admit it ... I did suggest water |
hehe no , it is fine. We are all dumb in all things except a few ones in this world. I dont know pretty much anything about chemistry either. And at
least you tried to help.
It doesnt work with water though. Even harder to separate it from water once the 2 are combined, than to separate it from ethanol
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JJay
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Most common solvents are miscible with ethanol, including diethyl ether.
Do you know what functional groups are in the compound(s) in the essential oil?
4A molecular sieves absorb ethanol, but some of the essential oil will stick to them as well.
I don't know if vacuum distillation will work or not, but an extremely strong vacuum might conceivably help to separate the alcohol.
The usual way to separate essential oils from plant matter is by steam distillation. It can be hard to produce much product that way on a lab scale.
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PirateDocBrown
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Oh, I see.
In the perfume industry, an extract via ethanol is called a "tincture", not an essential oil, which is what would be gotten via steam distillation.
What method you use for separation would depend heavily on what type of oil it is.
As JJay mentioned, the functional groups in the extract can bind with the solvent, preventing separation.
Why did you try salt water? Have you tried distilled water? Ethanol would mix freely, yet anything that would be in a true essential oil would
separate. Indeed, the salt could crash the ethanol away from the water, and leave it more with the extract.
What are you extracting? Perhaps another method would work better next time? Have you a Soxhlet? Even a cowboy coffeepot would be helpful.
What's often done is using one solvent for a first extraction (called a "concrete"), usually this is hexane. Then a second extraction gets the
fragrance out, leaving behind waxes, tars, and resins. (This is called an "absolute")
Alternatively, steam distillation is not as hard as all that. If you can do simple distillation out of water, and add more water as you go, that's
steam distillation. The oil just gets carried over with the steam, and floats on top in the collection vessel.
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khourygeo77
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| Quote: Originally posted by JJay | Most common solvents are miscible with ethanol, including diethyl ether.
Do you know what functional groups are in the compound(s) in the essential oil?
4A molecular sieves absorb ethanol, but some of the essential oil will stick to them as well.
I don't know if vacuum distillation will work or not, but an extremely strong vacuum might conceivably help to separate the alcohol.
The usual way to separate essential oils from plant matter is by steam distillation. It can be hard to produce much product that way on a lab scale.
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then ether wouldnt work. If there are solvents that may work, they must be immiscible, that also attract the essential oils from the alcohol. But I'm
not sure this is possible
Problem is I was going to work with many herbs simultaneously, and with new products with no information about. Others may be with known functional
groups but I dont think this method will be very effective
What may be effective is to find a solvent that reacts with alcohol, or form an azeotrope with it, and cannot dissolve the essential oil instead of
finding one for the essential oils which may be unknown most of the times. Problem is to find something that doesnt dissolve the essential oil too, as
most would
Yeah, you're right. It is not efficient at all to do that with water, takes much time, more complex equipment, extracts less oils. Some oils get mixed
with the water and cant get completely separated
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JJay
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| Quote: Originally posted by khourygeo77 |
then ether wouldnt work. If there are solvents that may work, they must be immiscible, that also attract the essential oils from the alcohol. But I'm
not sure this is possible
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It depends. If you can (perhaps temporarily) render the essential oil insoluble in ether, adding ether to it could cause it to separate. But that
certainly isn't going to work for every essential oil.
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khourygeo77
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| Quote: Originally posted by PirateDocBrown | Oh, I see.
In the perfume industry, an extract via ethanol is called a "tincture", not an essential oil, which is what would be gotten via steam distillation.
What method you use for separation would depend heavily on what type of oil it is.
As JJay mentioned, the functional groups in the extract can bind with the solvent, preventing separation.
Why did you try salt water? Have you tried distilled water? Ethanol would mix freely, yet anything that would be in a true essential oil would
separate. Indeed, the salt could crash the ethanol away from the water, and leave it more with the extract.
What are you extracting? Perhaps another method would work better next time? Have you a Soxhlet? Even a cowboy coffeepot would be helpful.
What's often done is using one solvent for a first extraction (called a "concrete"), usually this is hexane. Then a second extraction gets the
fragrance out, leaving behind waxes, tars, and resins. (This is called an "absolute")
Alternatively, steam distillation is not as hard as all that. If you can do simple distillation out of water, and add more water as you go, that's
steam distillation. The oil just gets carried over with the steam, and floats on top in the collection vessel. |
With 2 additional procedures, I can separate the alcohol with the volatile compounds in the residue, leaving all the non volatile compounds behind.
If I add water, I'll get a white solution, the whiter the more concentrated the oil in the alcohol. However nothing precipitates. But if I heat the
solution mildly, I'll see oils floating on the solution which I would sometimes separate, but this method isnt practical as not all the oils would
float and if the alcohol isnt filled with much oil, then nothing would float. It takes many reiterations on herbs in order to get the solution
saturated with oils
Salt didnt work at all. I tried to dilute the alcohol mixture with water, then add potassium carbonate. I could separate some oil from the alcohol,
but worse, the oil would permanently stick to the salt and I could do nothing to separate them. Alkalis absorb oils
The problem with steam distillation is it isnt really good. It only separates a portion of oils after applying strong heat and even many oils would
mix it with it, like anise and thyme giving it a whitish color. Nothing would float. It also extracts much less than alcohol or alcohol & water
and takes more time and doesnt nearly extract the things you can extract with alcohol or alcohol & water
If you can also find something that would separate an essential oil dissolved in water from it, it would be great. I distilled some time ago flax seed
and got so much oil with some volatile salts. Tried to separate the salts from the oil by adding water, but both would dissolve in the water
unfortunately
[Edited on 3-1-2017 by khourygeo77]
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PirateDocBrown
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You are extracting anise and thyme?
Have you done all your extraction, and are trying to save what you have for your product, or do you still have most of your botanical materials, and
are looking for a better extraction method for your next run?
Have you considered other solvents?
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khourygeo77
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| Quote: Originally posted by PirateDocBrown | You are extracting anise and thyme?
Have you done all your extraction, and are trying to save what you have for your product, or do you still have most of your botanical materials, and
are looking for a better extraction method for your next run?
Have you considered other solvents? |
No, I did this in the past. Now I'm working on other things (more complex) which arent herbs.
I tried working with acetone, doesnt work. Ammonia doesnt work. Ethyl acetate neither. The best thing seemed like alcohol. And I cant get my hands on
chemicals in here. I generally get stuff from the market, distill the solvent before using it.
I am always open or new methods, however after reading a lot, it seems that alcohol (diluted or not) will be the most convenient solvent. For herbs,
it is actually better to dilute the solvent with water as water extracts and brings over some compounds the alcohol doesnt. So you can say I am
looking for a way to separate oils from alcohol or alcohol & water as it seems to me the best solution and I could get very far with this method.
However, I am stuck at only the last phase 
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Sulaiman
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for oil/water separation these two bits of glassware are common
for light oil http://www.ebay.co.uk/itm/24-40-Oil-Water-Receiver-Separator...
for dense oil http://www.ebay.co.uk/itm/24-29-50ml-Glass-Oil-Water-Receive...
[Edited on 3-1-2017 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
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PirateDocBrown
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Ammonia? As in liquid ammonia? Impressive early choice!
Have you considered simple hexane? Or DCM?
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khourygeo77
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Ammonia dissolved in water. Got glass cleaner from the market and distilled it to get it. If I'm not wrong when ammonia is in water it gives Ammonium
hydroxide. It seems that it will attract some oils too rendering separation from the oils impossible. The smell of the ammonia in water will have
similar smell as the herb/fruit/wood/resin...
Hexane and DCM not available here unfortunately. It seems this is the distillers' favorite products today.
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khourygeo77
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The oil dissolves in the solvent, making separation impossible. They dont separate into 2 layers. This item allows separation when you have more than
1 layer if i'm not mistaken
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Sulaiman
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Or if you are rich, you could get a rotovap http://www.ebay.co.uk/itm/2L-Rotary-Evaporator-Rotovap-for-e...
[Edited on 3-1-2017 by Sulaiman]
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JJay
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That's cheap!
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PirateDocBrown
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Ammonium hydroxide is also quite reactive. I can see why it would make a poor extraction solvent. (Indeed, I've never heard of it used as such
before.)
Obtaining hexane is not at all difficult. Just fractionally distill some white gas (camp or Coleman fuel), and use the fraction that comes off around
50-60.
I get my DCM from paint stripper, though I strip out almost all volatiles, then clean up after.
If you are planning to use this as a product for human use, I'd go with the hexane, for lower toxicity.
[Edited on 1/3/17 by PirateDocBrown]
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khourygeo77
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What if it fails !! 
[Edited on 3-1-2017 by khourygeo77]
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khourygeo77
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| Quote: Originally posted by PirateDocBrown | Ammonium hydroxide is also quite reactive. I can see why it would make a poor extraction solvent. (Indeed, I've never heard of it used as such
before.)
Obtaining hexane is not at all difficult. Just fractionally distill some white gas (camp or Coleman fuel), and use the fraction that comes off around
50-60.
I get my DCM from paint stripper, though I strip out almost all volatiles, then clean up after.
If you are planning to use this as a product for human use, I'd go with the hexane, for lower toxicity.
[Edited on 1/3/17 by PirateDocBrown] |
Thanks for the info. I will consider using other solvents now. Not gonna stick to the ethanol forever.
I have done some search and found out these 5 common solvents used: DCM - hexane - Gasoline - Isopentane - Diethyl ether
I will be considering searching more about these products and possibly experimenting about them. Any idea where I can find the 2: Isopentane and
diethyl ether separable in a pure form? I see that diethyl ether can form peroxides I will be searching more into this
However, if I'm not wrong, toxicity shouldnt be an issue seeing that I will be separating the solvent from the oil. Actually, I would even wash the
remaining oil with water (by covering with water than evaporating) in case very little of the solvent sticks to the oil
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