alice_d25 (Stranger)
05-24-00 17:17
No 8756
      eucalyptus - mescaline  Bookmark   

I only just noticed an entry on RHODIUMS page describing the prep'n of syringaldehyde from e. lignum from a variety of Eucalypts.  Does anyone have experience with this reaction?

 
 
 
 
    Rhenium
(Stranger)
05-25-00 00:21
No 8903
      Re: eucalyptus - mescaline  Bookmark   

I am not aware of anyone who has tried the reaction, however the chmistry seems sounds. I guess the only initial problem would be the initial extraction of the syringaldehyde from the bark.

Rhenium

 
 
 
 
    Osmium
(Moderator)
05-25-00 12:47
No 9133
      Re: eucalyptus - mescaline  Bookmark   

Hi Rhenium!

I have done such reactions, but only for analytical purposes. You can oxidise lignin with nitrobenzene/aq. NaOH and produce a mixture of substituted benzaldehydes that way. Most refs detailing this procedure use a closed reaction vessel, meaning high temp and pressure. It can be done in a glass flask without high pressure, but the reaction rate will be very low. Good enough for analytical work when all you want to know is the ratio of the different benzaldehydes in the lignin, but not quite good enough for production.
One way to solve this dilemma might be using high-boiling solvents instead of aq. NaOH, I have seen aniline mentioned in one ref. But aniline is very toxic and hardly OTC so I can't recomend this variation.
Another big problem is finding the right lignin high in syringyl units. Separating the aldehydes will be very difficult, unless you use chromatography, which can't be used for production quantities.
I'll try to find some refs for this.

 
 
 
 
    ScuzZ
(Hive Bee)
07-04-00 16:02
No 24622
      Re: eucalyptus - mescaline  Bookmark   

Just a simple extraction like one you'd use to get DMT out of wattle leaves would do sufficiently.
Wouldn't it??
 
 
 
 
    Osmium
(Moderator)
07-04-00 17:47
No 24652
      Re: eucalyptus - mescaline  Bookmark   

Absolutely not! Lignin is a highly crosslinked polymer. For benzaldehyde production you have to degrade it by oxidation.

 
 
 
 
    Mr_Smith
(Hive Bee)
07-04-00 23:45
No 24789
      Re: eucalyptus - mescaline  Bookmark   

Lignin?! As in the stuff that holds wood together?  I've heard of the pyrolysis of lignin, but this fascinates me. Is there any way to depolymerize it and separate the phenol groups?

 
 
 
 
    Osmium
(Moderator)
07-05-00 12:13
No 24993
      Re: eucalyptus - mescaline  Bookmark   

Yes, lignin can be decomposed into the benzaldehydes (vanillin and syringaldehyde) by oxidative decomposition with nitrobenzene and NaOH. usually this temp is done in aq. solution at elevated temps (~170C), that means under high pressure. With the right solvent selection it might be able to do it at standard pressure. That's what I was talking about up there. Nitrobenzene smells nice (almonds) but is yuck, very poisonous. But I'm pretty sure nitrotoluene can be used too. If there is sufficient interest you might be able to talk me into digging out some refs for this.
The big problem is finding the best lignin for this task. It is dirt cheap as a precursor when you know the right industrial sources, and EU sponsors lignin research (renewable raw materials etc) with BIG bucks right now, but since vanillin is readily available you need a lignin which consists mainly of syringaldehyde. Best lignins I have seen yet consisted of only 50-60% syringyl units which is very difficult to separate from the rest (vanillin) by other means than chromatography. There migt be better lignins out there, like this eucalyptus lignin.
I think I posted more about all this on the old boards, maybe have a look there.