YES, this seems to have become a problem NOT only for you. Several members have addressed the same fuckin problem to me, and up till now we have not found a solution for this nagging big problem.
It seems btw conceiled only to the american subcontinent, including US and Canada.
It seems that one of the ingredients, formic acid, hydrogen peroxide, is the culprit.
If there is a hidden additive in there, then it will be quite difficult to find it.
What method of Isomerization did you use? KOH or Alliquat?
What is your main problem? The Isosafrole is already no good, or is it the distillation of the raw ketone AFTER the 15% H2SO4?
The 15% H2SO4 can be the problem, if the temp inside the reaction is not watched carefully then the reaction time of 2 hours can be too short and you have lots of unreacted isosafrole hanging in there. Lately Vibrating_Lights came up with the idea of checking your conversion to ketone with a blacklight lamp.
So you could take small reagens tube samples of your reactionfluid every 15 minutes or so, quickly boil off all volatiles and check the colour of your small sample of raw ketone mixed with still unreacted isosafrole!
Only problem could be: you introduce a lot of heat to boil off those volatiles in that test tube, thus interfering with the reaction itself. So better quickly boil off under high vacuum, it's worth the time taken for it in my opinion, because after doing this meticulously ONE time, you know exactly the point in time where your precious isosafrole has been converted maximal to ketone.
Any one know the data for his alcohol questions? LT/
WISDOMwillWIN