Vanillin-Based Polymers—part II: Synthesis of Schiff Base Polymers of Divanillin and Their Chelation with Metal Ions

Condensation of renewable resources-based monomer divanillin with alkyl diamines gives Schiff base polymers with degree of polymerization (DP) ~25–32 in 88–95% yield. These yellow polymers are insoluble in water and common organic solvents, slightly soluble in warm DMSO, DMF and dissolves in aqueous NaOH. The polymers were characterized using FT-IR, 1H, and 13C NMR spectroscopy and by comparison with the model compound N,N′-bis(vanillidene)-1,3-propanediamine. Polymer prepared by condensation of divanillin and 1,6-diaminohexane is shown to chelate with Cu(II), Fe(II), and Co(II) metal ions in basic aqueous methanol.