Author Topic: Safrole isomerization under vacuum  (Read 1439 times)

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bbeeasheets

  • 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?

Rhodium

  • 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).


ApprenticeCook

  • 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....

-AC


abolt

  • Guest
HMMMMMMM
« 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. ;)


hypo

  • Guest
hmmm...
« 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!  ;)


abolt

  • 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