A Conventional and Green Synthesis of 3,3`-([1,1`-biphenyl]-4,4`-diylbis(azanylylidene))bis(indolin-2-one) Derivatives, Potential Monomers for Schiff base Polymers, Using an Ionic Liquid Catalyst

Abstract

A number of 3,3`-([1,1`-Biphenyl]-4,4`-diylbis(azanylylidene))bis(indolin-2-ones) were synthesized by the conventional method and by a green method involving solvent-free phase transfer catalysis. The catalyst used is a quaternary ammonium salt aliquat 336. Mechanisms of reaction are proposed for the both synthesis methods. The structures of the products were confirmed by spectroscopic measurements. Schiff base monomers are good candidates for obtaining new polymers.