1

The paper https://www.hindawi.com/journals/jchem/2013/909217/ describes a possibility to synthesize salicylaldehyde-based Schiff Bases using water as a solvent. Yields shown for the microwave-assisted procedure are high, exceeding 90%, though the procedure requires no water removal, Dean-Stark equipment etc.

Is it the exception that proves the rule or the Schiff bases synthesis, in general, is always possible in aqueous media? Or maybe the microwave does the magic?

Marcin Stec
  • 51
  • 3
  • 2
    There's a passing reference to this at https://chemistry.stackexchange.com/a/89718/16683, although to stop anybody getting ideas, I'll say that this isn't a duplicate. – orthocresol May 05 '20 at 09:55
  • 1
    I wonder if the reactants are truly in solution, or are they esentially dissolving in each other as a microemulsion where reaction occurs. – Waylander May 05 '20 at 11:16
  • The reference post given by @orthocresol describes "conventional' i.e., not microwave-assisted reactions. The cited reference concludes that vacuum simply helps in the formation of imine by removing the water formed in the imine condensation. The case described in this post is different: solid product was obtained in reaction mixture. As far as I understand it means that water is present after the completion of the reaction. – Marcin Stec May 05 '20 at 11:44
  • 1
    I have two opinions here: (1) Microwave sometimes does weird things that make them superior to regular reactions, so that may just be it. (2) If this were a general reaction, I would assume that the paper would not refer to salicyladehydes and be in a better journal. – Zhe May 05 '20 at 14:19
  • Marcin Stec: That;s what exactly @orthocresol was saying. Your post is not a duplicate, but strangely similar. – Mathew Mahindaratne May 05 '20 at 19:56
  • The experimental section of the paper you cite says the product was filtered, not extracted. Thus, the equilibrium was shifted by precipitation of the product in the same way that a Dean-Stark trap shifts an equilibrium. I suspect the procedure may not be effective with aliphatic primary amines. – user55119 May 05 '20 at 22:12

0 Answers0