The Vespiary

The Hive => Methods Discourse => Topic started by: guyincognito on August 15, 2002, 03:35:00 AM

Title: Methanol distillation (vacuum)?
Post by: guyincognito on August 15, 2002, 03:35:00 AM
In methanol removal (distil) step right after the 36 hr spin in th cyano/amm acetate/ketone rxn. (this is the step that leave you with a whiteish jello sludge when the methanol is gone)

should one vacuum distill the methanol off?  Swim was reading TS2 and it said to vacuum distill in this step, but swim couldn't figure why?

Could it hurt the product?  to go only to like 60-65 C?
Title: anyone?
Post by: guyincognito on August 16, 2002, 07:38:00 AM
anyone?
Title: vacuum or simple distillation in solvent removal
Post by: Rhodium on September 02, 2002, 06:22:00 PM
Vacuum in removal of solvents is mostly used because it is way faster than atmospheric distillation. Just distill as usual when removing solvents, as long as you aren't removing high-boiling solvents as DMF or such things the extra heat applied compared to if you would have used vacuum usually makes no difference to your product.
Title: Vac distill methanol?
Post by: raffike on September 03, 2002, 02:49:00 PM
Vac distill methanol?One needs a good condenser to condense methanol vapours at 760mm already,under vac it seems to be impossible,unless ya have tha dry ice condenser.
A friend with speed is a friend indeed
Title: Either that, or you use an aspirator, where you ...
Post by: Rhodium on September 03, 2002, 03:23:00 PM
Either that, or you use an aspirator, where you don't need to care about condensing all the methanol.
Title: another alternative.
Post by: hypo on September 03, 2002, 03:31:00 PM
or, if you have one, you could use your chemical resistant membrane pump
and condense "behind" the pump.

(this is especially good if you don't want to polute your waste water with
halogenated or otherwise nasty solvents.)
couch terrorist