Sciencemadness Discussion Board - How to separate terpenes and sesquiterpenes dissolved in alcohol

How to separate terpenes and sesquiterpenes dissolved in alcohol

khourygeo77 - 19-2-2017 at 04:57

Hello,

I'm trying to separate terpenes and sesquiterpenes from alcohol without success. I tried to add water to form an emulsion but i cant break the emulsion. The solution would become white like milk but the terpenes dont float for some reason

If I heat however the diluted solution to around 50+ deg C, oil droplets appear on top. If I cool the solution again, oils go into the diluted solution again

Any idea?

JJay - 19-2-2017 at 05:13

Do the terpenes/sesquiterpenes form any azeotropes with the alcohol?

khourygeo77 - 19-2-2017 at 05:23

Quote: Originally posted by JJay

Do the terpenes/sesquiterpenes form any azeotropes with the alcohol?

Unfortunately, yes.

JJay - 19-2-2017 at 05:29

That's a difficult problem... possibly you could add something that would form a lower-boiling azeotrope with the ethanol. Obvious candidates would be ether and dichloromethane. It's hard to know if this would work without actually trying it.

Edit: scratch the ether idea. That definitely won't work. DCM *might*

[Edited on 19-2-2017 by JJay]

khourygeo77 - 19-2-2017 at 05:35

Quote: Originally posted by JJay

That's a difficult problem... possibly you could add something that would form a lower-boiling azeotrope with the ethanol. Obvious candidates would be ether and dichloromethane. It's hard to know if this would work without actually trying it.

Edit: scratch the ether idea. That definitely won't work. DCM *might*

[Edited on 19-2-2017 by JJay]

I was able to break this azeotrope once by freezing a dilute solution. Lots of oils (terpene family substances) floated on top, and some very tiny white salts fell to the bottom. I tried to repeat this process a few times to no avail.

JJay - 19-2-2017 at 05:37

Ethanol freezes at -114 C... that's pretty cold.

khourygeo77 - 19-2-2017 at 05:45

Quote: Originally posted by JJay

Ethanol freezes at -114 C... that's pretty cold.

The diluted solution freezes around 0 deg C. I'm working with dilute ethanol and not an absolute ethanol, as it seems the halfway to separate the terpenes as they arent soluble in water. What I do is dilute the ethanol with water, an emulsion forms as the oils are pushed away from the ethanol, and arent in solution anymore however stay confounded with the alcohol & water...

centrifuge works however i want another alternative

[Edited on 19-2-2017 by khourygeo77]

[Edited on 19-2-2017 by khourygeo77]

JJay - 19-2-2017 at 06:35

If a centrifuge works, you can try increasing the density of the water/alcohol solution by dissolving something in it. This should be something soluble in both alcohol and water.

PHILOU Zrealone - 19-2-2017 at 06:40

Maybe allowing HCl and NaNO2 to react with the ethanol...will set it free as very low bp ethyl nitrite (caution highly flamable and explosive atmosphere)...the terpènes and sesquiterpènes should remain unaffected.

JJay - 19-2-2017 at 07:10

Quote: Originally posted by PHILOU Zrealone

Maybe allowing HCl and NaNO2 to react with the ethanol...will set it free as very low bp ethyl nitrite (caution highly flamable and explosive atmosphere)...the terpènes and sesquiterpènes should remain unaffected.

I don't know about that. Farnesol, for example, would form an undesirable farnesyl nitrite or perhaps even a nasty 2-nitrosofarnesol.

khourygeo77 - 19-2-2017 at 08:16

Quote: Originally posted by JJay

If a centrifuge works, you can try increasing the density of the water/alcohol solution by dissolving something in it. This should be something soluble in both alcohol and water.

I am going to try dissolving salt. Not sure how much it gonna work considering it is insoluble in alcohol, and may probably push the alcohol into solution with the terpenes again(?). Will try to saturate the solution then freeze or put in the fridge. There dont seem to be many things soluble in both alcohol & water...

DJF90 - 19-2-2017 at 08:30

Are you sure your compounds form an azeotrope with Ethanol?

JJay - 19-2-2017 at 09:03

Quote: Originally posted by khourygeo77

Quote: Originally posted by JJay

If a centrifuge works, you can try increasing the density of the water/alcohol solution by dissolving something in it. This should be something soluble in both alcohol and water.

Potassium hydroxide comes to mind, but that might turn your oils into soap. Sulfuric acid wouldn't attack them as long as the concentration was kept reasonably low.

I would avoid using caustic and corrosive reagents for this if at all possible.

[Edited on 19-2-2017 by JJay]

PHILOU Zrealone - 19-2-2017 at 12:58

Quote: Originally posted by JJay

Quote: Originally posted by PHILOU Zrealone

I don't know about that. Farnesol, for example, would form an undesirable farnesyl nitrite or perhaps even a nasty 2-nitrosofarnesol.

Farnesol is not a pure terpene or sesquiterpene (pure CxHy)...it is a terpenol or a sesquiterpenol, thus a derivative.
The fact it makes a nitrite ester...will make it more volatile...but over C5 the nitrite esters are less volatile than ethanol (alcohol) and ethyl nitrite is a gas at ambiant T°...
Even if Farnesyl nitrite is formed it will be hydrolysed as soon as you boil it with water...no nitroso-farnesol would form...the alcohol group is not sufficiently activating like a nitro, keto or aldehyd group is vs its alfa position.

The only trouble I can see is addition of acids or nitrous oxyds to the double links...

True that knowing the terpernes or sesquiterpenes in question would help a lot...

[Edited on 19-2-2017 by PHILOU Zrealone]

JJay - 19-2-2017 at 13:35

Quote: Originally posted by PHILOU Zrealone

Quote: Originally posted by JJay

Quote: Originally posted by PHILOU Zrealone

I don't know about that. Farnesol, for example, would form an undesirable farnesyl nitrite or perhaps even a nasty 2-nitrosofarnesol.

It's not wise to assume that the OP means to exclude terpenoids and sesquiterpenoids. The terms "terpene" and "terpenoid" (and "sesquiterpene," etc.)are often used interchangeably. It's perfectly reasonable to suppose that terpenoids would be present in a tincture that contains terpenes. It would be rather surprising if there weren't any.

I'm not sure where the suggestion to boil water came from, but doing that carries the additional risk of causing whatever toxic components your proposed procedure might create to volatilize with steam. Also, farnesol has a double bond at the 2 position, so I'm not really sure what your point is about the alcohol activating group. Were you actually trying to make a suggestion that would help the OP deal with his problem?

This link contains additional information on why your proposal is an especially bad idea that could lead to the destruction of the OP's product. Check section 2.3.1.: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1574283/

PHILOU Zrealone - 19-2-2017 at 15:40

The solution to the problem of the OP is already given...ethyl nitrite is very volatile and will take all the ethanol away leaving behind all terpenes, sesquiterpenes or derivatives.
His problem was to get rid of the alcohol (what usually refers to ethanol) but keeping the (sesqui)terpenes.

The boiling (under reflux) is just to take care of your specific case of farnesyl nitrite...and hydrolyse back the nitrite to farnesol and HNO2 (N2O3 + H2O)...the heat will take care of the N2O3 to exit the system as a gas. This hydrolysis happens spontanously and immediately when water is present even into the cold...just like nitrite ester does form very fast (instantaneously from HNO2 and alcohol) this is a fast reversible equilibrium; by very strong contrast to any other esters (like nitric esters) that doesn't form that fast especially without dehydratants and doesn't hydrolyse that fast into water...nitrite esters do form when a huge amount of water is present...HNO2 can't exist without a lot of water.

The point with the alcohol not being activating...
R-CH2OH + HONO --/--> R-CH(-N=O)-OH..this never happens
but
R-CH2-CH=O + HONO --> R-CH(-N=O)-CH=O + H2O <----> R-C(=NOH)-CH=O
R-CH2-CO-CH3 + HONO --> R-CH(-N=O)-CO-CH3 + H2O <----> R-C(=NOH)-CO-CH3
R-CH2-NO2 + HONO --> R-CH(-N=O)-NO2 + H2O
Always happens.

I already know that document...it is related to nitrosyl chloride...a stronger nitrosating agent.
I have investigated all theoric papers and reactions of HONO, Cl-NO as OTC source of energetic materials or starting materials...because of the ease of preparation and high, fast yielding reactions...

This is why I was concerned by a possible interaction of HONO or N2O3 with double bonds...
--> "The only trouble I can see is addition of acids or nitrous oxyds to the double links..."

UC235 - 19-2-2017 at 16:23

Quote: Originally posted by PHILOU Zrealone

The solution to the problem of the OP is already given...ethyl nitrite is very volatile and will take all the ethanol away leaving behind all terpenes, sesquiterpenes or derivatives.
His problem was to get rid of the alcohol (what usually refers to ethanol) but keeping the (sesqui)terpenes.

The boiling (under reflux) is just to take care of your specific case of farnesyl nitrite...and hydrolyse back the nitrite to farnesol and HNO2 (N2O3 + H2O)...the heat will take care of the N2O3 to exit the system as a gas. This hydrolysis happens spontanously and immediately when water is present even into the cold...just like nitrite ester does form very fast (instantaneously from HNO2 and alcohol) this is a fast reversible equilibrium; by very strong contrast to any other esters (like nitric esters) that doesn't form that fast especially without dehydratants and doesn't hydrolyse that fast into water...nitrite esters do form when a huge amount of water is present...HNO2 can't exist without a lot of water.

The point with the alcohol not being activating...
R-CH2OH + HONO --/--> R-CH(-N=O)-OH..this never happens
but
R-CH2-CH=O + HONO --> R-CH(-N=O)-CH=O + H2O <----> R-C(=NOH)-CH=O
R-CH2-CO-CH3 + HONO --> R-CH(-N=O)-CO-CH3 + H2O <----> R-C(=NOH)-CO-CH3
R-CH2-NO2 + HONO --> R-CH(-N=O)-NO2 + H2O
Always happens.

I already know that document...it is related to nitrosyl chloride...a stronger nitrosating agent.
I have investigated all theoric papers and reactions of HONO, Cl-NO as OTC source of energetic materials or starting materials...because of the ease of preparation and high, fast yielding reactions...

This is why I was concerned by a possible interaction of HONO or N2O3 with double bonds...
--> "The only trouble I can see is addition of acids or nitrous oxyds to the double links..."

You consistently propose the most inane and dangerous garbage speculation I've ever heard in my life.

PHILOU Zrealone - 20-2-2017 at 03:09

Quote: Originally posted by UC235

You consistently propose the most insane and dangerous garbage speculation I've ever heard in my life.

???
I exposed the risk of flamability of the gaseous/volatile ethyl nitrite. Nitrite esters are commonly used in organic chemistry.
What other danger do you think about?
Carcinogenicity of ethyl nitrite as nitrosating agent?

I have worked with Thuja extract (thujone)...and it is also quite toxic and dangerous... so does many other terpenoids or sesquiterpenoids.

This is an OTC-ish way to get rid of the ethanol.
Do you have a better proposal to help the OP with his problem?

Why do you think it is garbage speculation? Could you elaborate a bit?

As explained I'm passionate about energetic materials and nitro, nitroso, nitrite, nitrate compounds amongst many others...

Amos - 20-2-2017 at 10:11

I don't buy that your terpenes co-distill with ethanol; I say this because my entire job for the last year has been separating, purifying, and producing terpene molecules. You might be distilling too aggressively and steam-distiling them along with all the water you have in this mixture. My advice is to extract the mixture using a low-boiling solvent such as DCM or diethyl ether and to simply evaporate the solvent off. Although since you say that the terpenes are freely soluble in your dilute ethanol, I doubt you have a very large mass of them; monoterpenes are poorly soluble in water at best and sesquiterpenes are extremely insoluble unless they are highly oxygenated derivatives.

Why anyone would suggest throwing dangerous, highly-reactive, and hard-to-obtain reagents at this problem when physical extraction is a perfectly valid means is beyond me.

What molecules are you working with exactly, anyway?

[Edited on 2-20-2017 by Amos]

PHILOU Zrealone - 20-2-2017 at 14:37

Yep..
"True that knowing the terpernes or sesquiterpenes in question would help a lot..."

But the OP doesn't answer.

Another problem is the mutual solubilisation of terpenes by terpenoïds with polar groups thus playing a role of non ionic detergents...and dus forming micellar droplets...probable reason of the cloudiness changing/varying with the temperature...

khourygeo77 - 22-2-2017 at 23:55

Quote: Originally posted by PHILOU Zrealone

As JJAY said, I dont intend to work with explosives/dangerous substances. And dont want to spend much money to separate essential oils especially when working on a more or less big quantities..

I worked lately with anise as it contains a lot of essential oils that will get distilled and so is easier to work on. I just hoped for a method that can help with all terpenes, and not a kind or 2. There must be considering that terpenes and sesquiterpenes form an emulsion with the water & alcohol combination

[Edited on 23-2-2017 by khourygeo77]

khourygeo77 - 23-2-2017 at 00:03

Quote: Originally posted by Amos

I don't buy that your terpenes co-distill with ethanol; I say this because my entire job for the last year has been separating, purifying, and producing terpene molecules. You might be distilling too aggressively and steam-distiling them along with all the water you have in this mixture. My advice is to extract the mixture using a low-boiling solvent such as DCM or diethyl ether and to simply evaporate the solvent off. Although since you say that the terpenes are freely soluble in your dilute ethanol, I doubt you have a very large mass of them; monoterpenes are poorly soluble in water at best and sesquiterpenes are extremely insoluble unless they are highly oxygenated derivatives.

Why anyone would suggest throwing dangerous, highly-reactive, and hard-to-obtain reagents at this problem when physical extraction is a perfectly valid means is beyond me.

What molecules are you working with exactly, anyway?

[Edited on 2-20-2017 by Amos]

Hello, thanks for your informative post I have worked for example on anise seed. The terpenes will only distill with the alcohol, and the alcohol is very rich in them. When I distill the alcohol, I get an a very strong louche. For example, in our country we make a drink called Arak, it consists of anise disitlled with water and alcohol and gives a high amount of oils. Everytime I try to fraction distill the alcohol, by heating on around 80 deg, I become able to separate the alcohol from the water. The water would be white containing some compounds which arent essential oils and seem like impurities, as it would be apparent after fraction distilling them. Only very few volatile compounds remain with the water upon distilling. However, the separated alcohol, would louche again greatly if I add water.

Arak may be similar to absinthe and such alcohol drinks made with anise...

And you mean I should add the volatile solvents to the alcohol&water mixture to strip them from their terpenes? Is this possible?

And I didnt say the terpenes are freely soluble in the dilute alcohol. I said they form an emulsion, which means they arent soluble. However, the emulsion will remain the same forever without breaking even after weeks.

[Edited on 23-2-2017 by khourygeo77]

Tsjerk - 23-2-2017 at 01:05

PHILOU, your method would give a mess. It was already quite clear from the first post it is, but definitely now it is clear this is an extract and with it there are a lot of different compounds in there which will all react in there own way; giving a mess.

I say try to make the water fraction heavier with something polarish, as suggested before, and centrifuge. I love centrifugation, separates the WORST of emulsions in minutes. Maybe you don't even have to make the water layer heavier.

@khourygeo77; do you have access to a centrifuge?

khourygeo77 - 26-2-2017 at 04:15

Quote: Originally posted by Tsjerk

PHILOU, your method would give a mess. It was already quite clear from the first post it is, but definitely now it is clear this is an extract and with it there are a lot of different compounds in there which will all react in there own way; giving a mess.

I say try to make the water fraction heavier with something polarish, as suggested before, and centrifuge. I love centrifugation, separates the WORST of emulsions in minutes. Maybe you don't even have to make the water layer heavier.

@khourygeo77; do you have access to a centrifuge?

I dont have access to centrifugation unfortunately

I need to find something available and cheap, soluble in both alcohol and water, or the oils will dissolve again in the alcohol, if i find something soluble in water only. I'm gonna try adding potassium acetate to oils in alcohol solution or in alcohol&water solution, and see if it makes the oils float

[Edited on 26-2-2017 by khourygeo77]