Hi bees!
Deemtermined: I once thought GAA just served as a solvent in Henry condensations, but I heard from my buddy SWIA that he recently tried using ammonium acetate catalyst with GAA/iPrOH solvent system, and got VERY ugly, red tar-like nitrostyrene (went down the toilet..). And then the question: why is the acetate made when ethylene diamine is used as catalyst (ED+2GAA=EDDA)? Perhaps the thought behind it is to avoid evaporating the catalyst (methylamine is even more volatile than ethylenediamine). Adding GAA to
nitrostyrene crystals makes no sense to me. But as you got nice nitrostyrene w/o GAA, may I suggest you simply don't add any...
(seriously, I suggest using EDDA)
Perhaps the following is a bit off-topic (I apologize) but the FSE is down at the moment, so I can't find the appropriate thread an have to ask here: SWIA has an OTC source for nitroethane, but the product in question contains ~40-60% NE, the rest being ethyl formate, ethyl acetate and butylalcohol. Although fractionally distilling several times, he hasn't managed to get high purity (at least all knoevenagel rxns gave him constantly 50-60% of the expected yield, with aldehydes, solvents and catalysts being lab-grade, and SWIA thinks the reason is his nitroethane) Since I wanted to help the poor guy, I suggested to make the nitronate salt by adding NE to aequ. KOH, then heating to remove EtOAc etc. (perhaps wash with nonpolar) and finally acidify and salt out the NE again.
Do you think my advice was right?
Or is there a simpler method for removing said impurities?
THX for your help!
A