Direct polycondensations of N,N′‐(4,4′‐oxydiphthaloyl)‐bis‐L‐leucine diacid by use of tosyl chloride in the presence of N,N‐dimethylformamide

Abstract

Abstract4,4′‐Oxydiphthalic anhydride (1) was reacted with L‐leucine (2) in acetic acid and the resulting N,N′‐(4,4′‐oxydiphthaloyl)‐bis‐L‐leucine diacid (4) was obtained in high yield. The direct polycondensation reaction of this diacid with several aromatic diols such as bisphenol A (5a), phenolphthalein (5b), hydroquinone (5c), 4,4′‐dihydroxydiphenyl sulfide (5d), 4,6‐dihydroxypyrimidine (5e) and 4,4′‐dihydroxydiphenyl sulfone (5f) 2,4′‐dihydroxyacetophenone (5g) and 2,6‐dihydroxytoluene (5h) was carried out in a system of tosyl chloride (TsCl), pyridine and N,N‐dimethylformamide (DMF). The reactions with TsCl were significantly promoted by controlling alcoholysis with diols in the presence of the catalytic amounts of DMF to give a series of optically active poly(ester‐imide)s (PEI)s with good yield and moderate inherent viscosity ranging 0.36–0.78 dL/g. The polycondensation reactions were significantly affected by the amounts of DMF, the molar concentration of monomers, TsCl and pyridine, aging time, temperature and the reaction time. All of the above polymers were fully characterized by 1H‐NMR, FT‐IR, elemental analysis and specific rotation. Some structural characterization and physical properties of these optically active PEIs are reported. Copyright © 2005 John Wiley & Sons, Ltd.