Comparative study of using ionic liquid and organic solvent for the preparation of optically active organosoluble polyamides with pendent 4-(2-phthalimidiyl-propanoylamino)benzamide groups
In this study, the direct polycondensation of chiral dicarboxylic acid monomer, 5-[3-phenyl-2-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)propanoylamino]isophthalic acid (1) with diverse aromatic diamines (2a-2h) was investigated in IL, 1,3-dipropylimidazolium bromide as replacement for volatile toxic organic solvents. The polymerization reactions were effectively preceded in IL, and triphenyl phosphite as an activating agent, and the resulting optically active polyamides (PA)s were obtained in a yield of 89-96% and inherent viscosities in the range of 0.54-0.71 dLg-1. The yields and inherent viscosities were comparative in this IL compared with analogous in organic solvents under milder reaction conditions. All of these polymers exhibited excellent solubility in many organic solvents. Characterization of the obtained PAs was studied by FTIR, specific rotation, 1H NMR, elemental analysis, thermogravimetric analysis (TGA) and differential scanning calorimetry.