Author Topic: Safrole isomerization under vacuum  (Read 7699 times)

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  • Guest
Safrole isomerization under vacuum
« on: October 07, 2004, 04:01:00 PM »
ok, i just purchased a sargent-welch 1405 duo seal vacuum pump. unbelievably to me, it distills safrole at 64C! (100 degrees lower than my last pump) my question is, i prefer to isomerize under vacuum (i heat to just boiling, but where it doesn't distill), and when boiling ceases the isomerization is complete. Will safrole isomerize (with KOH) at 60C?


  • Guest
Too strong
« Reply #1 on: October 07, 2004, 07:04:00 PM »
At 60°C the isomerization will take days, if it at all will go to completion. Use another pump or use a bleed valve with this one (something as low-tech as a leaky rubber tube is fine, adjust the vacuum by pricking holes into it with a pin).


  • Guest
all the vacuum is required for here is to...
« Reply #2 on: October 08, 2004, 01:33:00 AM »
all the vacuum is required for here is to remove excess water as this is a killer, but rhodium is right i use my aspirator... or just put deliberate leaks in the system you have.... but thats a nice pump for disto, good on ya!

Hey just a question from me....
Is there some relationship table/grpah around that has the isomerisation rxn times vs temp??? just so i know what the ideal temp for the rxn to be is to achieve the better yields....



  • Guest
« Reply #3 on: October 08, 2004, 01:48:00 AM »
The best kind of pump for isomerisation is one of those shitty teflon membrane pumps that pull 20-25" hg. ;)


  • Guest
« Reply #4 on: October 08, 2004, 02:34:00 AM »
is that 20-25 inch or mm?
if it's 20-25mm Hg, i'll take your "shitty" pump!  ;)


  • Guest
Ça Plane Pour Moi
« Reply #5 on: October 08, 2004, 02:40:00 AM »
(')= feet
(")= inch

25' would signify 25 feet
25" signifies 25 inch

Yeah, yeah I know.........I'm supposed to (Use metric units)

When I can find a mm/hg vacuum gauge for less than $2,000, I will throw away the old in/hg one. (sources welcome, please P.M.)

thanks for bringing it up, hypo