Ultra-rapid polyamidation reaction of optically active aromatic diacid containing methionine moieties with aromatic diamines under microwave irradiation

A novel aromatic dicarboxylic acid monomer, 5-[4-methylthio-2-(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)butanoylamino]isophthalic acid was synthesized starting from cis-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid anhydride and L-methionine in four steps. A highly effective, very fast microwave method is applied to synthesize optically active and thermally stable polyamides (PA)s under microwave heating for only 3 min. Generally, better yields are obtained under faster and cleaner reactions when compared to those from conventional heating. Therefore, this method could considerably reduce the synthesis time, cost, and energy. The resulting PAs had inherent viscosities in the range of 0.32–0.59 dL/g. All of the these polymers having bulky anthracenic and amino acid functionality in the side chain showed excellent solubility and readily dissolved in various solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide and N,N-dimethylformamide. PAs were thermally stable, with 10 % weight loss recorded at 400 °C and 450 °C under nitrogen atmosphere, and char yields at 800 °C higher than 41 % and glass transition temperature above 168 °C.