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Author Topic: Dr Drool method Viable?  (Read 2303 times)

pbinteger

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Re: Dr Drool method Viable?
« Reply #20 on: December 21, 2012, 11:40:25 PM »
I just re-ran the boiling point test -- in a test tube -- w/ my new thermometer.

the safrole boiled at 232 on the dot.

the isosafrole boiled at ~240

pretty good indication of what i've got here.

pbinteger

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Re: Dr Drool method Viable?
« Reply #21 on: December 24, 2012, 04:45:09 AM »
lugh -- thanks for that link.

I'm re-running the isomerization now a la Osmium's vacuum reflux. I made sure any water was boiled off under vacuum first as well... this one will work.

_Pbinteger_

pbinteger

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Re: Dr Drool method Viable?
« Reply #22 on: December 24, 2012, 08:37:29 PM »
Aaaaannndd... It didn't.

After 18 hours of vacuum reflux -- and fractional distillation -- lots of safrole. BP tested @ 232c.

The only thing I can guess is my vacuum is too strong so the temp was too low. This pump will distill safrole at 88c.

I'll re-try at atmospheric boiling off the water at 100c first.

Is the vacuum reflux isomerization best done at aspirator vacuum?

_Pbint_

jon

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Re: Dr Drool method Viable?
« Reply #23 on: December 24, 2012, 11:04:01 PM »
i think you need to do that with stirring to keep the solid KOH in contact the only reason for the vacum is to pull water so calibrate the vacuum to pull water at the temps your refluxing.
did you pestle those KOH flakes? to a fine powder?

pbinteger

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Re: Dr Drool method Viable?
« Reply #24 on: December 24, 2012, 11:47:37 PM »
I've done all these attempts with stirring. I did NOT grind up the flakes. Does that make or break this rxn?

I'm reattempting now at atmospheric pressure. It's hard for me to get an oil bath above 230c.

But I've got the oil boiling / refluxing. It's been doing so for a couple of hours and I haven't noticed a sharp change in the boiling point.

jon

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Re: Dr Drool method Viable?
« Reply #25 on: December 25, 2012, 07:42:21 PM »
use a sand or table salt bath you will be much happier if the oil spills on the plate it can ignite and ignite the pot of oil which would send you to a burn ward trust me you don't want that to happen.
yes the more surface area the better this is a liquid solid phase system
« Last Edit: December 25, 2012, 09:48:15 PM by jon »

d1ssonance

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Re: Dr Drool method Viable?
« Reply #26 on: December 27, 2012, 03:42:44 AM »
I've always been curious what kind of equipment is used for a vacuum reflux.

Can someone shed some light on the set-up vs. atmospheric. I obv. know how to set up for atm reflux.

Thanks.

fractal

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Re: Dr Drool method Viable?
« Reply #27 on: December 27, 2012, 06:39:33 AM »
Closed vacuum adapter attached to the reflux condenser. Besides that everything is the same as in reflux.

d1ssonance

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Re: Dr Drool method Viable?
« Reply #28 on: December 27, 2012, 07:11:23 PM »
LOL.

That easy huh.

I was worried that excess pressure would build up causing a stopper to rocket out.


Thanks.

pbinteger

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Re: Dr Drool method Viable?
« Reply #29 on: December 28, 2012, 02:00:15 AM »
So I'm finally returned from holidays and ready to distill my latest isomerization attempt.

When I attempted this last it was difficult to notice any change in boiling point which doesn't give me tons of faith that it was successful. After receiving the advice from jon to grind up the KOH I did and added some to the stirring / refluxing oil. Before I started this attempt I put the whole thing under hard vacuum with a liebig condenser to pull of any water. It was under mild heat (100c) and stirring vigorously. I did not notice any water condensation.

How does one know if the water is out if there is only miniscule amounts of water in it to begin with? Is water the only likely culprit for failure here?

Thank YOU!
_Pb_

pbinteger

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Re: Dr Drool method Viable?
« Reply #30 on: December 28, 2012, 07:48:44 PM »
boiling point test failed -- distillate boils at 230 -- rolling boil at 232c....

I must be failing to get the water out! Let me make a few adjustments and run another experiment.

WTF!?

« Last Edit: December 28, 2012, 08:09:31 PM by pbinteger »

pbinteger

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Re: Dr Drool method Viable?
« Reply #31 on: December 29, 2012, 12:13:42 AM »
OK

I just redistilled a bunch of sass oil and and re-running the isomerization using a large heating mantle. This time I actually saw water come through the condenser which is a first. I also let it reflux at just below the bp of safrole for an hour with vigorous stirring to be sure all the water was out. Now I'm going to let it stir at 150c overnight.

Hopefully it will work this time.

_Pbint_

pbinteger

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Re: Dr Drool method Viable?
« Reply #32 on: December 30, 2012, 05:14:48 PM »
Isomerization success!

89% yield of 170g safrole -- 151.3g isosafrole. Boiling point test passed. I'd like to improve my technique on the isomerization. After refluxing it at ~160c for 24 hours with stirring all of the ground up KOH had turned to black gunk. I had read in other hive archive posts that you can reuse the KOH to run subsequent isomerizations but this stuff did not look reusable. It was surprisingly easy to remove with dish soap and water, but I'm not sure how much product was lost in the gunk or how much could have been recovered with a good DCM wash. I think I will try washing the flask with DCM next time to get up to the 95% yield range as written by OcoteaCymbarum from the Hive.

The glycol / epoxide has been forming for almost 24 hours now and it looks exactly like what is pictured in the write up by OcoteaCymbarum.

It looks like this:
http://parazite.nn.fi/hiveboard/picproxie_docs/000528375-orangejuice.jpg

Going to perform the pinacol rearrangement today. I will use HCL as written in the above hive archive.
I'll post how much ketone is yielded.

I've attached a pic of the rxn in it's final hour of stirring.

_Pbint_
« Last Edit: December 30, 2012, 05:49:32 PM by pbinteger »

HandoftheSon

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Re: Dr Drool method Viable?
« Reply #33 on: December 30, 2012, 08:20:42 PM »
89% ain't shabby. Close to those yeild's jon raves about.

nice job!

jon

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Re: Dr Drool method Viable?
« Reply #34 on: December 30, 2012, 10:56:41 PM »
yeah but that's just isosafrole at 89% by the time you get through all the other steps it's more like 70% overall and it's a big pain in the ass.
so i like 3 simple steps and no distillations and 90+ % yeild you can't beat that.

pbinteger

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Re: Dr Drool method Viable?
« Reply #35 on: December 31, 2012, 04:28:42 AM »
jon -- you're route is certainly cleaner and higher yielding, but knowing other routes is never a bad thing -- it's always fun to learn new routes.

_Pbint_

Sneak

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Re: Dr Drool method Viable?
« Reply #36 on: December 31, 2012, 05:02:00 PM »
Go pbint go! Good work man!
If you really want to enjoy a pure, clean product the only way... is to make it yourself...

You miss 100% of the shots you don't take...

pbinteger

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Re: Dr Drool method Viable?
« Reply #37 on: December 31, 2012, 09:06:27 PM »
100g ketone...

not great yields. I really have a lot to learn about this route -- many ways to improve my technique.

but not bad for a first run...

There's still a bunch of dark oil in my flask I was using to do fractional distillation.. but it was not coming over at the same temp as the rest of the ketone -- does this mean it's all just trash? I was heating it a bit more in hopes it would come over and I melted the rubber on my clamps! LOL! so I stopped it for now to get the goods into the freezer.

Pic attached.

jon

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Re: Dr Drool method Viable?
« Reply #38 on: December 31, 2012, 10:42:37 PM »
sometimes when you distill ketones leftover bases can cause aldol style condensations especially if you distill it hot.
so make sure your water washes come out neutral and some of your shit can be partially soluble in water so back extract always.

poisoninthestain

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Re: Dr Drool method Viable?
« Reply #39 on: January 01, 2013, 08:52:14 PM »
The ketone could be a bit more pale but should work fine for subsequent reactions IMO. What temp did your suspected ketone come over under reduced pressure? also aspirator or pump? Should have a licorice smell with some floral overtones at least to me...definitely different than safrole.

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