The Vespiary

The Hive => Newbee Forum => Topic started by: bbeeasheets on October 07, 2004, 04:01:00 PM

Title: Safrole isomerization under vacuum
Post by: bbeeasheets 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?
Title: Too strong
Post by: Rhodium 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).

Title: all the vacuum is required for here is to...
Post by: ApprenticeCook 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....


Post by: abolt 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. ;)

Title: hmmm...
Post by: hypo 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!  ;)

Title: Ça Plane Pour Moi
Post by: abolt 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