biffman (Hive Bee)
08-23-04 20:29
No 526965
      Safrole isomerization using n-Butanol     

I was wondering if any bees could give any feedback on using KOH in n-Butanol as a solvent for isomerizing safrole.
  According to Rhodium's site it can give a 98-99% yield.  SWIM has tried most other methods but is always discouraged by the vast amounts of tarry crap also formed and in general the poor yields.  I was wondering if the tarry by-products are less of a hassle using the n-Butanol method?  SWIM has been using his n-Butanol for methylamine purification but wondered if it might be put to this possibly more important use and since the safrole is almost all gone doesn't want to experiment needlessly.
 
 
 
 
    ApprenticeCook
(Hive Addict)
08-24-04 01:57
No 526994
      Well i have never had a problem with the ...     

Well i have never had a problem with the no-solvent method, dont know what your doing but all i get is the shitty residue of KOH in the bottom, and thats easily removed to get ~95-98% isosafrole molar yield.


But try the solvent methods, and the yields are slightly better, if its reported on rhodiums site, someone had to have tried it...

-AC

Its just my opinion, but no-one listens to me anyway, and rightly so...
 
 
 
 
    biffman
(Hive Bee)
08-31-04 15:05
No 528480
      That's what I would expect also.     

It seems to be only recently that there has been a problem with lots of tar and goop formed from the isomerization.  At first I thought somehow the safrole was decomposing somehow during storage so it was distilled prior to the isomerization yet still produced significant tar during the non-solvent method. Have tried using constant vacuum as well as only initial vacuum to remove the water with similar results.
  Isn't some water formed during the conversion which should be removed? thus requiring the constant vacuum?
  Oh well.  There's plenty of n-butanol available and experiment is king.
 Thanks for the input.