Chemical Forums
Specialty Chemistry Forums => Citizen Chemist => Topic started by: pantone159 on March 09, 2006, 11:43:50 AM
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I am on the lookout for natural products (e.g. herbs, spices) that could make interesting chemistry experiments.
There are various places on the web that sell a variety of herbal things and I figure some should have interesting chemistry.
Examples:
Spearmint has (R)-(-)-carvone, while caraway seed has (S)-(+)-carvone, these mirror images smell different to most people.
Red cabbage is a pH indicator.
Turmeric/curcumin is also.
Tea contains caffeine. (I am working on extract it now...)
Any other suggestions?
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Mark,
Let me know how your caffeine extraction goes. I did this not to long ago with okay results.
Joe
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I am getting a headache trying to search this forum for a past post on extracts of herbs. That link would have a discussion about the poisonous effects of herb and spice concentration. Someone else fine the link and post it.
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I did find this thread:
http://www.chemicalforums.com/index.php?board=9;action=display;threadid=3049;start=msg12617#msg12617
And I have to admit that I didn't search before I posted my question :-[
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How about steam-distilling spices/herbs and then doing separation of the compunds in the essential oil?
Fennel
Anise
Basil
Thyme
Nutmeg
Black pepper
Estragon
Rosemary
Lavendel
Cardamom
Dill
Parsley
Coriander
I could tell you loads more, but these are common and easy to get and work with. Some glassware and a vacuum source is a big plus... ;)
At pharmacies around here you can get a mix of essential oils to make your own "glögg", which is a kind of spiced wine you drink warm at christmas time.
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Mark Kness thank you
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What's the solvent of choice for chemically extracting extracts from natural things? Denatured alcohol or acetone? (I could make chloroform...but, pass!)
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science2000 -
None of the ones you mentioned seems particularly tasty.
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I and probably most people here don't have a lab full of exotic solvents. I do have a bathroom and garage chemicals. ;D
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What about extracting eugenol from cloves? :)
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What's the solvent of choice for chemically extracting extracts from natural things?
I think that steam distillation is ideal, but I don't have the glassware now.
Alcohol (190 proof stuff sold as "Everclear") is my first choice solvent, less toxic than alternatives.
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Mark Kness - What about using 160 proof grain alcohol as in vodka?
science2000 – The solvents you mention might make the extracts toxic which I believe is not the goal of essential oil extraction for human utilization.
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I think that steam distillation is ideal, but I don't have the glassware now.
Yes, steam distillation can be pretty ideal. I highly recommend you get some glassware and equipment for that if you already have space for a lab. It's more fun too. ;)
Just remember that essential oils and natural extracts are far from often suitable for consumption. Sometimes they are pretty toxic. I guess you already knew that, I just want to remind you and anyone who reads the thread about it.
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I highly recommend you get some glassware and equipment for that if you already have space for a lab.
I don't suppose Mark wants to get arrested ;)
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I don't suppose Mark wants to get arrested ;)
Texas does have stupid glassware laws. If I ever speak of a 'flask', that is a hypothetical comment. I really would mean a beaker that is shaped like a flask. ;)
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Mark Kness - What about using 160 proof grain alcohol as in vodka?
That would probably be fine. Less water is better, you usually don't want anything that dissolves in water. But 160 proof is pretty strong.
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Texas does have stupid glassware laws. If I ever speak of a 'flask', that is a hypothetical comment. I really would mean a beaker that is shaped like a flask. ;)
Yes - Texas' glassware laws are very strange....
Joe
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Holy s#*$! You're not even allowed to have glassware? :o
Sounds pretty bigbrotherish and like a hindrance of development to me. This world is really taking a turn I don't like. I guess you have to be security checked and ISO-certified to turn on the coffe machine soon...but that's another discussion.
FFS
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billnotgatez
science2000 – The solvents you mention might make the extracts toxic which I believe is not the goal of essential oil extraction for human utilization.
If I ever extract something, it's just for the sake of having cool extracts. Like, in organic II lab we isolated caffeine from coffee, and it' formed interesting little crystals. Acetone is polar aprotic and alcohol is polar protic, so these solvents are very different. Acetone seems to be used for alots of things.
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Thanks for the suggestions, btw. I will keep these in mind for future experiments.
Two examples I didn't mention before, that might be interesting:
- Extracting nepetalactone from catnip. (This might violate forum rules, at least for cats.)
- Extracting capsaicin from peppers. (This might be dangerous. SEVERE irritant!!)
These links have some info:
http://www.chm.bris.ac.uk/motm/chilli/
http://www.chm.bris.ac.uk/motm/chilli/fun.htm
The NEXT natural products extraction I plan to do, in any case, is DNA.
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BTW - Is there any standard reference that lists the composition of various natural oils/products?
I.e. if I wanted find out what is in nutmeg, where would I want to look first?
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BTW - Is there any standard reference that lists the composition of various natural oils/products?
I.e. if I wanted find out what is in nutmeg, where would I want to look first?
Not exactly what you asked for but this is interesting reading:
http://en.wikipedia.org/wiki/Nutmeg
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Thanks. Wikipedia is actually a pretty good source for this kind of information.
I have decided that the first part of this project is a 'library research' part where I try and look up what chemicals are in what spices and learn something about then. Only later will I try and do any lab stuff. Wikipedia is proving very useful in this.
mike - Do you have any more details on how to extract eugenol from cloves?
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I did the extration of eugenol in uni not too long ago, for quite a while my lab book 'smelled of christmas' from where i collected the stray ground cloves on a page, if you want i can send you the lab manual for that experiment, the file will be a pdf.
I'm James by the way, 21 yr old 1st year chemistry student at Birmingham uni, hey all.
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I did the extration of eugenol in uni not too long ago, for quite a while my lab book 'smelled of christmas' from where i collected the stray ground cloves on a page, if you want i can send you the lab manual for that experiment, the file will be a pdf.
I'm James by the way, 21 yr old 1st year chemistry student at Birmingham uni, hey all.
James, welcome... If you wouldn't object I would like to have a copy of this as well.
Thanks,
Joe
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I did the extration of eugenol in uni not too long ago, for quite a while my lab book 'smelled of christmas' from where i collected the stray ground cloves on a page, if you want i can send you the lab manual for that experiment, the file will be a pdf.
I'm James by the way, 21 yr old 1st year chemistry student at Birmingham uni, hey all.
Hello there, welcome... I'd be interested in the manual.
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Mark Kness: Steam distillation would be the way to go. Oil of Clove is composed to large extent of eugenol. If you can't get real lab glassware, improvise. The temperature won't be very high because it's steam distillation, so many things can be used.
I'm sorry if I'm yacking too much about steam distillation. ;)
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Anyone who wants a copy of the lab manual just send me an e-mail (james_gore1984@hotmail.com), by the way my account is down at the moment so you might not get it until tomorrow.
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I was recently reading about aroma therapy and massage therapy. In both they use essential oils which are sometimes mixed with base oils. In many cases they say that the oils are created via cold pressing rather than a heated process. I assume that they feel that heating will reduce the properties of the essential oils. The effect would be similar to an egg white turning from sort of clear liquid to a sort of white solid. Of course, what goes on in egg cooking involves a protein rather than oil. Many of the essential oils had warnings as follows:
Do not use if pregnant.
Do not expose yourself to UV light (sunlight) after application.
Do not use on sensitive skin.
Do a very small test on skin 24 hours to full use.
One wonders if the cold pressing is also done to make sure that you get not only the oils but also the other juices in the plant. That would give you all the liquid parts plus any dissolved solids. That way you get the synergistic effect of all of the compounds in the juice and not just one single constituent.
The reading source I used was from Readers Digest. It kept me occupied while waiting for a ride.
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The reading source I used was from Readers Digest. It kept me occupied while waiting for a ride.
which edition? i want to read it too, sounds interesting :)
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It was a separate book published by Readers Digest about massage and aromatherapy.
I will try to get the title etc.
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Anyone who wants a copy of the lab manual just send me an e-mail (james_gore1984@hotmail.com)
Thanks, James, that was useful. This seems like a good extraction experiment.
The procedure is basically to steam distill ground cloves to get clove oil, and dissolve this in dichloromethane (DCM). Then, this is extracted with NaOH solution. The eugenol (which has a phenol-like -OH part) loses the proton and then goes into the water layer. Then, this water layer is acidified, giving the eugenol the proton back and this is extracted with more DCM. Dry, filter, and evaporate the DCM to recover eugenol.
I think I could replace the steam distillation (since I don't have the equipment) by extracting the ground cloves in EtOH, then evaporating most of that, dissolving that in DCM, and proceeding from there. Not as slick, but it should do.
This works well because eugenol has the phenol part that can be acid-base extracted. (Soluble in water at high pH, insoluble at low pH).
Another promising extraction might be piperine from white pepper. (Black pepper has lots of piperine too, it is most of the flavor, but it does have some other things. White pepper is, I think, more pure piperine.)
http://en.wikipedia.org/wiki/Piperine
This has a nitrogen, so it would also be amenable to acid-base extraction. (Protonate the N in acid, making it water soluble, but insoluble when deprotonated in base.)
Another fun project might be to isomerize estragole (from tarragon)
http://en.wikipedia.org/wiki/Estragole
to anethole (licorice flavor)
http://en.wikipedia.org/wiki/Anethole
which, I think, can be done by heating with base. This would change tarragon smell to licorice smell, which might be interesting.
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This was the Reader's digest publication I mentioned in a previous post
Hands on Health
Subtitle – Health and healing the natural way
ISBN: 0-7621-01466
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Results from my eugenol extraction experiment:
Instead of steam distillation (I don't have the equipment), I decided to extract the eugenol from cloves by soaking it in 95% EtOH. I put around 25 g of powdered clove into a flask-shaped beaker, and added c. 70 g of 95% EtOH, and let this digest for a couple of weeks with occasional swirling. (I was not in any hurry.) I filtered this off, and added a similar amount of fresh solvent, let it digest again, then filtered, and combined the two filtrates which were green liquids. I evaporated c. 2/3 of the solvent, and then pretended like this was what I got from steam distillation.
My extraction procedure plan, based on the stuff from James Gore as well as some other sources I could find was:
Extract from the initial stuff, with 25,20,20 mL dichloromethane (DCM). Combine these extracts, then wash the DCM with 25,25 mL water. Extract from the DCM with 30,25,25 mL of 5% NaOH. Wash the NaOH with 15 mL DCM.
Next, acidify the NaOH (with 5% HCl) to pH 1. This step was a little different in the various procedures I read. James' proc said to acidify to pH 9, others said pH 1, I aimed for 1. The mixture turns cloudy as it becomes acidic.
Extract the acidified aq solution with 20,25 mL DCM. Wash this DCM with 15 mL H2O, then 15 mL of half-saturated NaCl solution. Take the DCM, add anh MgSO4 to dry, filter, and evaporate the solvent, yielding eugenol.
When I started to actually do this, the first part had a complication. I added the DCM to my EtOH extract, but I did not get two layers. So, I added c. 20 g of H2O to force separation to occur. After that, it mostly proceeded as planned. I need to improve my drying technique, my final DCM solution wasn't in fact dry from the amount of MgSO4 I used. Anyways, I did end up with a small amount (c. 0.25 g) of a yellow-brown oil which I assume is eugenol.
I'm not sure what yield I should expect, but I think my results (c. 1 % yield) are very low. I think the reason is that the initial EtOH extraction didn't take up most of the eugenol. I don't think I lost that much in the processing. (After evaporating the waste DCM portions, there did seem to be some eugenol in there, along with a bunch of other goopy junk, but not enough to explain the low yield.)
So, I think I really did want to use steam distillation, after all. :)
In any case, I did get some eugenol, so I am happy.
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At pharmacies around here you can get a mix of essential oils to make your own "glögg", which is a kind of spiced wine you drink warm at christmas time.
mmmm, gløgg! :-)
I learned in my surviving training to extract water soluble compounds from needles on trees to make some sort of a tea.