Sciencemadness Discussion Board

easy separation of 4-(dimethylamino)benzaldehyde from benzaldehyde

Maddr33 - 16-3-2015 at 00:59

I really just want to use separatory funnel.
but I can't figure out what would go into the aqueous levels..
Solvents: acetone, ethanol, methanol, ethyl acetate, hexanes, dichloromethane
Aqueous solutions: 1M NaOH, 1M HCl, 3M NaOH, 3M HCl, 1 M NaHCO3, saturated NaCl
Drying Agent: sodium sulfate
I have to test for purity too. of 4-(dimethylamino)benzaldehyde

Chemosynthesis - 16-3-2015 at 13:29

Learn how to evaluate pKa's. That alone will likely solve the last two posts you've made. Basic qualitative purity testing is also available in most texts/lab books.

Boffis - 16-3-2015 at 14:09

@ Maddr33 Your posts are starting to appear as though we are answering your homework question. True?

Steam - 16-3-2015 at 16:01

I am actually sort of curious how to use pKa's to solve this. I am just thinking with the more basic amino group that a more acidic aqueous layer would be more propitiate for extraction but then again I am just guessing. :)

Chemosynthesis - 16-3-2015 at 17:32

Propitiate is a verb.

As to the chemistry, you have a protonable amine and a second material that is more soluble in ether (miscible according to Hawley's) than water (Kirk Othmer). Could verify in CRC, Merck, or Lange's. I don't want to go spoon feeding the OP questions they could learn to answer for theirselves, school or not (though it is legitimate to ask). They clearly haven't even considered melting points, if not a school question....

Steam - 17-3-2015 at 08:07

Quote: Originally posted by Chemosynthesis  
Propitiate is a verb.

Don't know what I was think with propitiate- must of been late! Thanks Chemosynth, I was just curious about the problem!