The Vespiary

The Hive => Methods Discourse => Topic started by: TheBlindGenius on March 18, 2004, 01:57:00 AM

Title: MM Wacker Scaleup, is it feasible?
Post by: TheBlindGenius on March 18, 2004, 01:57:00 AM
Read in a past post someone said the methanol wacker doesn't work well when scaled up??  Why not?  What if it was scaled up 2x or 2.5x in a 5L flask?  Don't want to waste 400g precursor oil so speak now or forever hold your peace  :P   It would be great to be able to produce 250g ketone in one big batch

Title: Do you want to try this?
Post by: Grouch on April 17, 2004, 05:32:00 PM

Post 171271 (missing)

(LaBTop: "Successfull DMF O2 Wacker", Methods Discourse)
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It's bigger than the 250g, by about ten times!  but you might have to get some new equipment and chemicals.
Title: Which Wacker?
Post by: borolithium on April 22, 2004, 11:34:00 PM
The benzo wacker works fine on a large scale when used with methanol. Mutli kilo batches are not a problem.

On the other hand, I have found methanol in the 02 Wacker to never work, producing some kind of fucked up anti freeze substance that won't aminate.

DMF is the preferred substance for the 02 wacker and to the best of my knowledge, is quite scaleable.
Title: More than that!
Post by: borolithium on April 28, 2004, 01:31:00 AM
I've had no problem with multi kilo dreams of the benzo wacker, without any significant decrease in yield. A five gallon vessel with a 45/50 3' reflux condenser works great.

Title: scale up and distillation..
Post by: runne on April 29, 2004, 10:54:00 AM
On larger scale benzo's would you then distill the crude MDP2P in batches?

Would trying to distill 500ml's at a time increase the amount of polymerization happening? Does the Aldol reaction come into play here?

And regarding the washes, how critical is it for the last washes to be dH2O to remove all traces of base/acid to limit polymerization?

What would be the optimal batch size for distillation given good 24/40 glassware and a vacuum of about 1.5 torr?