Room temperature ionic liquids as replacements for organic solvents: Direct preparation of wholly aromatic polyamides containing phthalimide and S-valine moieties
Ionic liquids (IL)s are often considered as green solvents capable of replacing traditional organic solvents and have extensively studied in material chemistry and catalysis. In this work a new class of wholly aromatic and optically active polyamides (PAs) having phthalimide and S-valine pendent groups were prepared by the reaction of 5-(2-phthalimidyl-3-methylbutanoylamino)isophthalic acid as a diacid monomer with various aromatic diamines. ILs media in the presence of triphenyl phosphite was used as a condensing agent. The resulting novel optically active PAs with inherent viscosities ranging from 0.35–0.71 dLg−1, were obtained in excellent yields. This method of polymerization was also compared with direct polyamidation using conventional phosphorylation reaction. Introduction of bulky and flexible clusters in these polymers pendent group, make them readily soluble in most organic solvents. The resulting polymers show optical rotation, therefore, are optically active.