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nightflight
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Extraction of eugenol
Hi there,
I´ve last nite tried to conduct an experiment, that I saw on the web, from the Universty Tübigen, -extracting eugenol from cloves, the only
modification being, that I used cloves oil
and extracted with ether, instead of tert butyl.
So everything was set up right, the oil was shaken with 10% K2CO3 and then
separated, leaving a reddish oily residue, considered to be acetyleugenol, and a waterphase.
The waterphase was made acidic with 2M HCL-acid; -used approx. 120ml, until the fizzling stopped and (no ph-paper, but on the way!) acidicity was
reached for sure,... (another experiment used those 10% (oh)- and titrated to ph1, there, they used 5% (oh)- and titrated to ph3).
the aeq. phase was three times extracted with stabilized ether, then evap. under vacuum and slight heat applied, leaving nearly no oil.
What happened?
Tried again, about 10ml of an oily residue, which should have been -as indicated as the eugenol content of the oil, about 140ml at least.
Anyone tried this experiment for teachers apporbation ?
nightflight
[Edited on 31-10-2006 by nightflight]
[Edited on 31-10-2006 by nightflight]
[Edited on 31-10-2006 by nightflight]
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solo
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Reference Information Interesting Reading
Extraction of clove using pressurized hot water
S. Rovio,1 K. Hartonen,1 Y. Holm,2* R. Hiltunen2 and M.-L. Riekkola1
Flavour Fragr. J., 14, 399±404 (1999)
Abstract
Subcritical water extraction was used to extract eugenol and eugenyl acetate from clove at various temperatures and pressures where water was in
either the liquid or gas (steam) phase. Several solid phase materials were tested in order to quantitatively and selectively collect the analytes
after the water extraction.
Quantitative collection of eugenol and eugenyl acetate could be achieved using a C18 solid phase trap. The extraction kinetics with subcritical water
was very fast at high temperatures (2508C and 3008C), giving a 100%
recovery after 15 min for eugenol and eugenyl acetate, compared to extraction at 1258C, where the same recovery was achieved only after 80 min
extraction. In addition, both eugenol and eugenyl acetate proved to be stable at the highest extraction temperature (3008C) used in this study.
KEY WORDS: Syzygium aromaticum (L.) Merr. et L. M. Perry pressurized hot water; subcritical water; steam; extraction; adsorbents; eugenol;
eugenyl acetate
Attachment: Extraction of clove using pressurized hot water.pdf (152kB)
This file has been downloaded 2234 times
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Nicodem
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I doubt you can effectively form a stabile solution of the phenolate salt of eugenol with 10% K2CO3. You should use NaOH. Beware that the sodium salt
of eugenol tends to precipitate when concentrated, so extract with 5 to 15% NaOH(aq) solution. With clove oil this forms a yellow solution. When you
neutralize it, the eugenol precipitates as oil. Unless you use minuscule amounts there is not even any need to extract with ether since eugenol is
nearly insoluble in water.
Is there any special reason for doing this?
("…that I saw on the web, from the Universty Tübigen…" <= Dont be so lazy! Provide a link or reference! How are we supposed to check what
procedure you followed?
"…and extracted with ether, instead of tert butyl." <= terc-butyl what?)
[Edited on 31-10-2006 by Nicodem]
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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solo
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Here is a practical approach as it's a lab procedure with some questions to see if one understood the excercise..............solo
Attachment: extraction of eugenol from cloves.pdf (204kB)
This file has been downloaded 98200 times
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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nightflight
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Thanks, I see that the failure lies in the K2CO3, must be KOH or NaOH...any ways to recover it?
Here´s the link that´s been requested by solo ;-) just search for eugenol in the file, please... http://www.uni-tuebingen.de/ziegler/EinfPraktOC_Praktikumssk...
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Nicodem
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The write up for those educational experiments explicitly say that the clove oil is extracted in 3% NaOH and not K2CO3 as you claimed
in the first post.
| Quote: | Originally posted by nightflight
Thanks, I see that the failure lies in the K2CO3, must be KOH or NaOH...any ways to recover it? |
Recover what? (Your use of pronoun "it" is too ambiguous to understand what you are referring to.) If you mean the clove oil, then there is nothing to
recover since you were unable to dissolve it in K2CO3 anyway. So nothing is lost in the first place.
Edit: Corrected to K2CO3 what before was Na2CO3.
[Edited on 31-10-2006 by Nicodem]
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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nightflight
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That´s what I mean, thanks, so what I supposed to have guessed to be the acetyleugenol is in fact the cloves-oil, alltogether, except some phenolat
~like 10gr., which I was able to salt out with the ether extractions.
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unionised
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Looking on the bright side, you have removed any carboxylic acid impurities from the stuff.
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nightflight
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If there ever had benn any in cloves oil...
so far so good, looks like it´s going as it´s supposed to be.
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nightflight
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it is now a brown sludge and a yelllow aequos liquid on top...
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nightflight
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Allrigth, I consider this extraction as failed
I did it with another oil and it turned burgundy red with the addition of the 10% Na(oh) and some smears of refracting oil are present but it
wouldn´t separate ...
I think I ´ll take up this oil in ether, longing to get the aequos
phase separated; -this one is then going to be titrated with HCL(aq.) and extracted ... In a paper with a nanoscale extraction and examination of
cloves oil, with conescutiv chromatography, concluded, that the cloves oil they were investigating, in fact, is pure eugenol.
I think this might be true, anyway I dont want to waste my hard earned pyridine hcl on pure oil of unknown indegrents, to demethylate the ring
substitutes.
But then again, why not? -too afraid of losses and sideformation in further reactions/uses with it...
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unionised
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I just wonder if a solution of the sodium phenoxide acts like soap and spoils things. Adding a bit more water might help the separation- if not then
it hardly matters- you are still stuck with the ether extraction.
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nightflight
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I´ve let it sit for a few hours now and finally separation appeared- it looks very much, from the volumetric point of view, that the percentage of
Eugenol /Acetyleugenol of 80/20 for most sorts of clovesoil holds true, in this trial.
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nightflight
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As Eugenol is slighlty more dense than water would it be better to use a bottom puller like dcm?
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Sandmeyer
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Uhm, "bottom puller"? To extract the oil you can use DCM, ether, ethyl acetate, it has nothing to do with the density -- read a book before inventing
own science! It' would be boring to see sciencemadness decadence to the level of crystal meth forum and bluelight, yet there seems to be an invasion
from these places lately.
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Nicodem
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| Quote: | Originally posted by nightflight
... In a paper with a nanoscale extraction and examination of cloves oil, with conescutiv chromatography, concluded, that the cloves oil they were
investigating, in fact, is pure eugenol.
I think this might be true, anyway I dont want to waste my hard earned pyridine hcl on pure oil of unknown indegrents, to demethylate the ring
substitutes. |
Nightflight, with all due respect, you are a fool for not listening what others say to you. Already in my first reply I told you not to be lazy and
provide information that can help others to help you. Assuming that there will be clairvoyants at this board to answer you, and that thus you do not
have to write any references, details of what you did, what you want and what went wrong, is plainly a (very) stupid assumption.
For example, if you would have told us that you are doing these "experiments" in order to obtain eugenol, somebody would have told you that clove oil
is de facto eugenol. Clove oil generally contains 90-95% eugenol, the rest being mostly just O-acetyleugenol, O-methyleugenol, moisture and
traces of some terpenes. O-acetyleugenol, the major "impurity", hydrolyses to eugenol during most reactions that one would want to perform with
eugenol anyway, so there is no need to remove it. How pure you think chemical grade eugenol is? Well, it is about 98%.
[Edited on 6-11-2006 by Nicodem]
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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unionised
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Nightflight may have invented some new nomenclature- it's certainly not a term I have heard. But his point is a valid one. Since ether is less dense
than water and eugenol is more dense there must be a mixture that has the same density as water. Sod's law means that you may get close to that
mixture when trying to extract eugenol. If there is no difference in density then there is no impetus for the 2 layers to separate.
Using DCM as the extraction solvent avoids this problem.
Also, My trusty copy of the Merck index gives clove oil as containing "82-87%eugenol including about 10% acetyl eugenol, caryophylene..." (The
important word ther is including)
So (assuming the book's right) Clove oil is about 10 or 20% miscellaneous crap that you don't want.
If I were in the habit of trying to make drugs or any other product, I'd be fussy about my statring material's purity, at least to the extent of
getting rid of that much junk that easily.
Of course, maybe the book's wrong and he read the same text as I did.
On the other hand, he may have read an old copy of the British Pharmacopoeia (1963) which specifies between 85 and 90% eugenol v/v (Measured by
extraction with KOH for 30 min).
What you say clove oil should be is not consistent with this (albeit rather elderly) specification or with the Merck index. May I ask where you got
your data from?
I know that, as a student, I extracted eugenol from clove oil. I'm sure we must have been removing something when we did that alkali dissolution;
wash with ether; reacidify bit.
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Nicodem
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| Quote: | Originally posted by unionised
Nightflight may have invented some new nomenclature- it's certainly not a term I have heard. But his point is a valid one. Since ether is less dense
than water and eugenol is more dense there must be a mixture that has the same density as water. Sod's law means that you may get close to that
mixture when trying to extract eugenol. If there is no difference in density then there is no impetus for the 2 layers to separate.
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No. When you neutralize the phenolate solution you get the eugenol layer on top, not on the bottom (trust me, I know). Eugenol has the density of
1.067 g/mL at 25 °C and is thus lighter than the other layer consisting of the aqueous solution of salts and HCl.
And his point is not valid. It only shows he has no practical lab skills since anybody with experience in organic chemistry would know that it is
irrelevant where the precipitated oil goes. The extractions are done by shaking in the separatory funnel, so how could it matter what the density of
the product is? You choose the extraction solvent by extraction/solubility/volatility properties and lighter/heavier than water mainly for practical
reasons (lighter when you want to keep it in the separatory funnel, heavier when you want it out, etc.). By the way, even if two liquids are of
completely identical density, they still separate due to surface tension causing aggregation in larger drops.
| Quote: | | What you say clove oil should be is not consistent with this (albeit rather elderly) specification or with the Merck index. May I ask where you got
your data from? |
From the specifications by the company I brought it from. But anyway, different plant sources, different climates, different production processes give
different purity. According to this paper: "The main chemical content of the clove oil is eugenol (70 to 98%)." So the content may vary even more than you or I thought. But this
is irrelevant since this guy wants to use eugenol in a demethylation reaction and both major impurities (O-acetyl and O-methyl) transform into the
same product as eugenol does in the procedure he mentioned.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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unionised
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It's always been my habit to water wash extracts like that after the extraction so the density really does matter. For what it's worth I have enough
practical lab experience to know that separating 2 liquids with the same density in a sep. funnel simply doesn't work. (The 2 phases separate, but
they don't form layers)
It's still my opinion that removing the trash before you start is a good idea. Granted most of the impurities will convert to the desired product but
it still leaves the question of what happens to the other stuff. Since, as you point out, the natural product is variable, it seems all the more
important to clean up the fraction you want.
It seems harsh to judge the man a fool for trying to start with a clean material. The circumstances are such that I'm not putting money on it, but
perhaps he wants to find the yield of the reaction or to experiment to get the best yield. Not cleaning up the eugenol just adds another uncontrolled
variable.
[Edited on 6-11-2006 by unionised]
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ziqquratu
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Dont know about anyone else, but I've been faced any number of times with horrible emulsion-like messes when trying to extract using solvents of the
wrong density. For example, after doing a reaction in ether, trying to extract with DCM has caused serious problems. And this has been the case with
MANY reactions, not just a one-off.
Thus, to avoid any chance of this problem, I now always extract with a solvent of the appropriate density. Usually, I try to extract using whatever
solvent I used for the original reaction. Otherwise, I use ether or DCM (occasionally ethyl acetate in place of ether) as is appropriate to the
situation.
In the case of eugenol extraction, I dont know for certain whether eugenol is more or less dense than water, but I'd use a solvent with has a similar
density to avoid emulsions.
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nightflight
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| Quote: | Originally posted by unionised
It's always been my habit to water wash extracts like that after the extraction so the density really does matter. For what it's worth I have enough
practical lab experience to know that separating 2 liquids with the same density in a sep. funnel simply doesn't work. (The 2 phases separate, but
they don't form layers) |
That´s what I came across while doing it, and the second attempt didn´t do as
well, either.
That´s what´s chemistry, especially organ. chemistry is about ... you don´t really know it, unless you´re experimenting it -that´s why it´s
called ´experiment´ and even then, when a procedure is found, there might be differences that´d invtervene with reaction and product outcome,
sometimes.
| Quote: |
It's still my opinion that removing the trash before you start is a good idea. Granted most of the impurities will convert to the desired product but
it still leaves the question of what happens to the other stuff. Since, as you point out, the natural product is variable, it seems all the more
important to clean up the fraction you want.
It seems harsh to judge the man a fool for trying to start with a clean material. The circumstances are such that I'm not putting money on it, but
perhaps he wants to find the yield of the reaction or to experiment to get the best yield. Not cleaning up the eugenol just adds another uncontrolled
variable.
[Edited on 6-11-2006 by unionised] |
Well, saying that there are no carboxylic salts, ment, that it´s rather pure eugenol
I thought it was rather clear, that I wanted to get the eugenol as the main fraction, but that would have been a guess to the objective "third party",
but that´s not even the point -when I´m doing an experiment, I want to get as close to the described literature involved, as possible and obtain
results with all the bells an whistles, as described, plus some inside views of the procedure and practical meachnisms of it and, of course, the
involved chemistry, which unfortunately (?) comes a little short on most boards, or drug-procedures and literature-abstracts, so I think best would
be, to get the inside knowledge by studying adaequate literature myself and on boards like this.
If it weren´t interesting and such a wide field, I´d rather baking cakes and spent my money otherwise.
So now, the cloves oil was demethylated by microwave irradiation using pyridine*hcl + cloves oil mol.ratio 0.05 - 0.01 in a stoppered flask and was
irradiated 8 times fror 2 min. on ~230w, with cooling inbetween, using a little less pyr. as i´m short of it right now, but it seemed to work to
completion nonetheless and my instincts tell me, that the ratio might have been even lower, maybe if some more cycles of irradiation were applied with
this one, as psychocitty hints on rhodium...
An amber colored solid was obtained, the smell of the pyr. and cloves oil has dissappeared; here´s a link to the paper that ´s using this method of
demethylating or "deprotecting" an ehter by dmethyletion of methyl aryl-ethers: http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleFo...
So now, the reaction content has to be worked up as stated.
[Edited on 7-11-2006 by nightflight]
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indigofuzzy
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I hope this doesn't come across as a stupid question, but how would one extract clove oil from ground cloves?
::lights clove cigarette::
BTW, IIRC, eugenol is a type of anaesthetic, right? That would explain why my tongue used to go numb from smoking Djarum Blacks. 
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not_important
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Steam distillation is an easy method. Works best when you can return the distillate work to the still pot. But you'll find whole cloves noticably
cheaper than ground, you can crush or grind them yourself.
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Ephoton
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thanx again spoil sports stop it leave it alone we know
stop posting about X do you want them to take this away too.
god eugenol is defanatly no the easist way these days and thats
with out sassy. get some brains and think of what the hive did
to sassy so just keep on letting all the children know how to stop us.
all this shit is easily found out by prac I think this place would agree
earn it dont talk it.
[Edited on 10-11-2006 by Ephoton]
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chemoleo
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Again, this is a chemical forum, not a drug one. So please, no disclaimers are required, particularly of authors who assert to 'get some brains' but
cannot get fundamental spelling or capitalisation right.
Just keep it strictly chemical and professional, that's all we ask for. And k3wl 'sassy' names are certainly not helpful, nor wanted.
Never Stop to Begin, and Never Begin to Stop...
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