Sciencemadness Discussion Board

Extraction of eugenol

nightflight - 31-10-2006 at 06:46

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]

solo - 31-10-2006 at 08:03

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 2227 times

Nicodem - 31-10-2006 at 08:16

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]

solo - 31-10-2006 at 08:40

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 98156 times

nightflight - 31-10-2006 at 09:23

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...

Nicodem - 31-10-2006 at 09:50

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]

nightflight - 31-10-2006 at 09:53

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.

unionised - 31-10-2006 at 10:05

Looking on the bright side, you have removed any carboxylic acid impurities from the stuff.

nightflight - 31-10-2006 at 11:41

If there ever had benn any in cloves oil...:D

so far so good, looks like it´s going as it´s supposed to be.:cool:

nightflight - 31-10-2006 at 11:51

it is now a brown sludge and a yelllow aequos liquid on top...

nightflight - 5-11-2006 at 09:40

Allrigth, I consider this extraction as failed:mad:
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.:o

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...:D

unionised - 5-11-2006 at 13:15

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.

nightflight - 5-11-2006 at 13:50

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. :cool:

nightflight - 5-11-2006 at 14:02

As Eugenol is slighlty more dense than water would it be better to use a bottom puller like dcm?

Sandmeyer - 5-11-2006 at 15:40

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.

Nicodem - 6-11-2006 at 01:31

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.:o

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]

unionised - 6-11-2006 at 13:01

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.

Nicodem - 6-11-2006 at 13:52

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.

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.

unionised - 6-11-2006 at 14:11

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]

ziqquratu - 6-11-2006 at 18:41

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.

nightflight - 7-11-2006 at 11:04

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 :o

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]

indigofuzzy - 10-11-2006 at 03:11

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. :P

not_important - 10-11-2006 at 08:28

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.

thanx again spoil sports stop it leave it alone we know

Ephoton - 10-11-2006 at 15:29

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]

chemoleo - 10-11-2006 at 18:53

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.

nightflight - 10-11-2006 at 21:52

I really dont´ know what the fuss is all about, come on, it´s a standard experiment and I really wonder why it´s so hard getting the e. out of the oil, it doesn´t separate well, if let sit, it crystallizes
out in the water layer, when it finally formed, it´s shitty to titrate and gets a sludgy mess of e. when finished.:D

Finally, I wouldn´t mess with saparation, if someone wanted to process the oil any further, unless strictly needed. I did it out of curiousity for the process, because it´s part of my collegue class and I couldn´t tell any difference between pure eugenol and the oil.

Ephoton - 13-11-2006 at 03:48

as you say boss please forgive this miss guided snowflake.
no more cool words just iupac.
I still belive that if this is not a drug site its very border line.
just becouse your porn shop sells newspapers does not mean its
not a porn shop.
but you are right I should keep a standard equal to thouse around me.

Ephoton - 13-11-2006 at 03:56

Personally I would just vacuum distill with a good column much nicer in my books even done it.
It takes no time at all. no mess no smell, cloves are not my favorite smell reminds me
of tooth aches.

nightflight - 13-11-2006 at 09:14

Yeah, but better than the smell of blood and bones in your mouth.^^

Quite a good anaesthetic, I stand in wonder how powerful such an neat little goody of mother nature´s parfumery exerts such power, when rubbed on the gum.:o
And I wonder too, why it´s so seldomy used in i.e. standard cleaning procedures at your dentist, i.e. when they´re scratching off the plaque from the toth-neck splattering off the tips of your gum in your whole mouth, jeess, I called for an injection after teeth nr. 3 was scrubbed off, by that ugly old lady.

Fract. distilling is another technique that I need having under my belt and pracitced, but everything worked out allright, studying the facts and work-up of some smart people on this subject is everything -really need to be an expert in every detail of what you´re doing and then forgetting it again, because it´s simply too much.:cool:

I think its best to

blacksnowflake - 14-11-2006 at 05:33

learn the basic nature of different types of compounds and how to purify/clean
them then try and apply that common knowledge to the compound you are interested
in. there are many ways to purify something. but they don't all work for every
compound. Vacuum distillation is a great way to work as most organics
can be purified this way if there is a large enough separation in temperature
between wanted compound and impurities.