title: Synthesis and characterization of novel, optically active polyamides derived from S-valine natural amino acid and bulky anthracenic side chain.
abstract: This is the first description of the application of molten tetrabutylammonium bromide (TBAB) in the presence of triphenyl phosphite (TPP) for the synthesis of novel polyamides (PAs). Monomer diacid, 5-[(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)-3-methylbutanoylamino]isophthalic acid (4), having anthracenic and amino acid S-valine pendant group, was synthesized in four steps. Several novel, optically active PAs were prepared by the condensation of synthesized diacid monomer 4 with various aromatic diamines using two different techniques: a mixture of N-methyl-2-pyrrolidone (NMP)/TPP/pyridine/calcium chloride (method I) and combination of TPP with TBAB (method II). The main goal of the present paper was to prepare novel PAs in a green media by removal of toxic reagents. Therefore, TBAB/TPP was used as a novel, easy, safe and eco-friendly method for the preparation of aromatic PAs. This method is compared with the polymerization reaction under conventional solvent and in the case of TBAB as a new method, higher yields, inherent viscosities and thermally stable of PAs are gained. The resulting polymers showed good solubility in polar aprotic solvents such as dimethyl sulfoxide, NMP, N,N-dimethylacetamide and N,N-dimethylformamide. These polymers are characterized with respect to chemical structure and purity by means of specific rotation experiments, FT-IR, 1H NMR spectroscopy techniques and elemental analysis. The obtained PAs exhibit good thermal stability up to 335°C for 10% weight loss in nitrogen atmosphere and glass transition temperatures fell in the rang of 177-185°C.
authors.affiliation: Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, 84156-83111, Isfahan, Iran. mallak@cc.iut.ac.ir
authors.forename: Shadpour
authors.initials: S
authors.lastname: Mallakpour
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Mirkarimi
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009757:Nylons / Q000138:chemical synthesis* / Q000737:chemistry*; D017905:Phosphites / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012995:Solubility; D013237:Stereoisomerism; D013696:Temperature; D014633:Valine / Q000737:chemistry*
chemical_list: D009757:Nylons; D017905:Phosphites; D000644:Quaternary Ammonium Compounds; C013318:triphenyl phosphite; C009405:tetrabutylammonium; D014633:Valine