Sciencemadness Discussion Board

Solid-Liquid Azeotropic Distillation

GreenD - 25-4-2013 at 14:11

This paper
http://www.ncbi.nlm.nih.gov/pubmed/18498150

describes a procedure:
"The product was azeotroped with toluene and the resulting solid was used in the next step."

I am wondering what the best apparatus would be for this, as any condensation (incorrect term) of the solid is going to be a mess to clean up from a regular distillation apparatus. I can't find much with "solid azeotrope distillation" with UTFSE

S.C. Wack - 26-4-2013 at 15:08

Relevant physical properties of this product and resulting "solid" are not described, so I'm unsure why I must assume problems. Assuming the product is a solid, mechanical stirring is the only extra thing about this in many cases; not even that, if the flask and amount of toluene is large in comparison or the solid is light/fluffy. And if the product does stick to the RBF, it is presumably dissolved in a solvent in the next step?

kristofvagyok - 27-4-2013 at 03:52

Add some toluene, distill it using a Dean-Stark trap till no more water comes over and distill it till all solvent comes over and be happy with the remaining dry solid.

Nicodem - 6-5-2013 at 08:39

Quote: Originally posted by kristofvagyok  
Add some toluene, distill it using a Dean-Stark trap till no more water comes over and distill it till all solvent comes over and be happy with the remaining dry solid.

The procedure does not call for such a treatment. It only says that the residue after rotavaping was "azeotroped with toluene" which does not involve any refluxing or Dean-Stark traps. Besides, this question was already raised in a recent thread.