Author Topic: Eugenol Q's  (Read 1051 times)

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ylid

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Eugenol Q's
« on: April 09, 2003, 03:52:00 AM »
I thought I would teach myself a bit of org chem by mixing a few substances together in my bathroom. Strictly legit.

Now I'm happy to experiment but I need some background info too. So I found a nice website on steam distillation of cloves [

http://members.aol.com/profchm/Chapt6-4.html

] and with a bit of help from Zubrick wound up with 100ml or so of reasonably pure eugenol from a kilo of cloves. (My old lady was down on me for making the food processor stink evermore of crushed cloves though, so for future reference I have identified a dirt cheap source of clove oil from a company that does stuff for body decoration. I guess it's like a slow-evaporating solvent for pigment that also does for local anaesthesia.)

Damn if that shit hasn't turned brown! I tried to keep it out of the light, but I was a bit careless about exposure to air. So my first two questions are:

  1.   Is this auto-oxidation? What has it auto-oxidized to? How might I remove the oxidized impurity?
  2.   Would adding a bit of hydroquinone prevent the auto-oxidation? How much should I put in?

God have mercy on me, but I've told the old lady that I'm making some vanillin for home soap manufacture. She doesn't believe me because I never wash, but her official position is that anything that gets me out of her hair makes her happy, so long as she gets to use the other bathroom. So for our mutual happiness:

  3.   What is the best way to oxidize eugenol to vanillin? The full method seems to involve isomerization, acylation, oxidation, and hydrolysis. Can I get away with just banging the eugenol in a pot with alkaline KMnO4, or do I have to isomerize at the very least?

If it looks like the route from eugenol to vanillin is too involved, I'm going to make an alcoholic extract turmeric and oxidize the curcumin to vanillin. Check it out! Two molecules of vanillin for each one of curcumin  :) . I reckon p-hydroxy-benzaldehyde turns up as a side product, maybe 10% of the product, which might be useful for something. Methylate to a nice aniseed smell perhaps. By the by, curcumin is useful for making indicator paper.

  4.   I think alkaline KMnO4 should do it, but can anyone provide some hints about the reaction conditions, like how much alkali, how long, what temperature?
  5.   Assuming I eventually end up with vanillin somehow, would hydroquinone do to prevent auto-oxidation?

With the left over eugenol I might try making a little elemicin. Because I heard it smells so nice. Might be good in some kind of soap too. I have some rather basic questions about the method, which I am too embarrassed to put on the thread

Post 381882

(GC_MS: "Eugenol -> elemicin and myristicin", Novel Discourse)
.

  6.   The Duff formylation is supposed to be low yielding, but I don't know if that is because eugenol remains unreacted or because side products are formed. The sodium salt of the 5-formyl product is supposed to crystallize out of alkaline solution, but if unreacted eugenol were present, wouldn't the sodium salt of eugenol also crystallize out? GC-MS does not do the bisulfite adduction which would separate out the aldehyde product - is that because it is low yielding, or because it is not really necessary?
  7.   I don't have any pyridine for the Dakin reaction. Is this just a cosolvent or is a N-containing base necessary for teh reaction somehow? Merck tells me that adding betaine to hot alkali gives trimethylamine. Would an aqueous or methanolic solution of trimethylamine work instead of pyridine?
  8.   I am planning to use betaine for the methylation step as well, not because I think it will work better than dimethyl sulfate, but because it's cheap and safe. Does anyone have any recommendations about the reaction conditions for that? It looks like somewhere between 3-6h at somewhere between 150-250°C. Trimethylamine boils off as a by product and could (potentially) be recycled to the previous step.

Any other suggestions or info on this method would be very welcome.