Fast Synthesis, Using Microwave Induction Heating in Ionic Liquid and Characterization of Optically Active Aromatic Polyamides

A simple pathway for the preparation of optically active aromatic polyamides (PAs) is reported. A fairly inexpensive and readily accessible molten ionic liquid, tetrabutylammonium bromide (TBAB) was used for the synthesis of polymers. PAs were synthesized from polycondensation of (2S)-5-[4-(4-methyl-2-phthalimidyl pentanoylamino)benzoylamino]isophthalic acid with various commercially available diisocyanates in N-methylpyrrolidone (NMP) as common organic solvent and molten TBAB as a green medium with or without dibutyltin dilaurate as a catalyst under microwave irradiation. Polycondensation process in TBAB is safe and green since toxic and volatile organic solvent such as NMP was eliminated. Various PAs were obtained with high yields and moderate inherent viscosities in the ranging from 0.26 to 0.91 dL/g. The obtained polymers were characterized by FT IR, specific rotation measurements, 1H NMR, elemental and thermogravimetric analysis techniques and differential scanning calorimetry.