Resorcin[4]arene Schiff base derivatives: Synthesis, characterization, and extraction studies

Abstract

Novel 2,6-dihydroxyacetophenone[4]arene derivatives with an electron-withdrawing group at the ortho-position are developed. The 2,6-dihydroxyacetophenone[4]arene derivatives are condensed with benzylamine in chloroform to give the Schiff base derivatives of resorcin[4]arene. The acetyl group of the 2,6-dihydroxyacetophenone[4]arenes is condensed with primary amine groups to form imines. The multifunctional target molecules are purified and isolated in good yields. The Schiff base derivatives are characterized by elemental analysis, 1H and 13C nuclear magnetic resonance spectroscopy, infrared spectroscopy, and mass spectrometry. All the Schiff base compounds are successfully used for the extraction of toxic metals including Ni2+, Mn2+, Hg2+, Co2+, and Na+ using a liquid–liquid solvent extraction process. Among these tested metals, the percentage extraction of Hg2+ is the highest. As sodium dichromate has greater oxidative stability to transfer the HCr2O7− anion from an aqueous a protonated ligand solution, an anionic extraction study of dichromate is tested at various pH values.