The Vespiary

The Hive => Newbee Forum => Topic started by: experimentalbois on February 10, 2003, 06:33:00 PM

Title: To Reflux Or Not To Reflux....
Post by: experimentalbois on February 10, 2003, 06:33:00 PM

A friend of a friend does not reflux when doing his wacker; instead he does his wacker exactly like MM says to do it, but just drips in his saf/MeOH mix over an hour, caps it, and lets it stir for 8 hours or so....Brightstar also said nothing of refluxing here....so is my friend right(brightstar too) or does refluxing make a real difference?? I mentioned this in an earlier post, but no one responded...I also did some searching today(TFSE) and no one referred to not refluxing when it's called for during the wacker....

Title: yes, to reflux is the answer
Post by: hCiLdOdUeDn on February 10, 2003, 07:22:00 PM

You should reflux. If you cap it and heat is evolved your cap will pop off and alot of methanol is evaporated and lost and will end up in a failed reaction. If a condensor is attached and cold water is running through, the vapors will condense and will drip back into the flask, and the cycle continues. This is what a reflux is.

Title: Brightstar's and MM's wackerrs are the same...
Post by: pickler on February 11, 2003, 02:15:00 PM

Brightstar's and MM's wackerrs are the same but use different alcohols as the medium for the reaction to take place. Bs uses dmf and this wacker creates its own heat so only stirring is needed. MM uses methanol which requires heating to a reflux to get decent yields. Try the search engine, it has been discussed many times before.