Structural characterization of oligomers from the polycondensation of citric acid with ethylene glycol and long‐chain aliphatic alcohols

Abstract

Abstract The structural characterization of polyesters of citric acid (CA) with ethylene glycol and long‐chain aliphatic alcohols (ROH), prepared by the composition of the reaction mixture being adjusted slightly away from stoichiometric equivalence, was performed with 1 H‐ and 13 C‐NMR spectroscopy. The aliphatic alcohols employed were 1‐decanol, 1‐dodecanol, and 1‐octadecanol. The 13 C‐NMR carbonyl region presented four groups of signals, two corresponding to the ester groups and two corresponding to the acid groups. However, symmetric and asymmetric groups of CA moieties were identified in the 13 C‐NMR spectra. The ester yield from ROH decreased as the number of carbon atoms in the alcohols increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 302–306, 2003