mercvap01 (Stranger)
10-23-01 14:51
No 228137
      Benzo Wacker question  Bookmark   

After reading about Methyl Mans benzo wacker method I had a few questions.  What percentage of the forerun was isosafrole?  He claimed `100 - 120g MDP2P from 178 safrole but did not differentiate iso from this I am assuming.
(Pioneer Researcher)
10-24-01 10:54
No 228389
      Re: Benzo Wacker question  Bookmark   

When you finally distill your product, you will see first a small  fraction of safrol, then another fraction of iso and then the ketone, with a yiled of may be 60 % molar from safrol. With single distillation you'll have a bit of saf and iso with your ketone, it will react the same. Store it in the freezer immediatly.
I've not performed this rxn, but I understand it. It seems that when you distill some solids could appear in the refrigerant and even contaminate the ketone, it is because benzoquinone sublimes. Make the washes correctly and good luck..
(Commodore "Mole Bouncer")
10-24-01 19:35
No 228517
      Re: Benzo Wacker question  Bookmark   

it variies depends on the rxn, sometimes eneough forerun to be worth collecting 20-25ml, sometimes all you see is s smooth rise on the thermometer right to the temp the ketone rolls over, no steps along the way.

"All those memories lost like rain..."
(Hive Bee)
10-25-01 01:03
No 228623
      Re: Benzo Wacker question  Bookmark   

>all you see is s smooth rise on the thermometer right to
>the temp the ketone rolls over, no steps along the way

this is a good point for the newbees.  if you change your vacuum source between distilling your safrole and distilling your ketone, you may not know where to expect it to come over.  it's not always easy to tell what is saf, iso, or ketone, especially when it's your first time. 

change as little as possible, introduce as few variables as possible.  in case you haven't figured it out yet, this is a learning experience. laugh