Synthesis, characterization, and kinetic investigation of acrylic monomers derived from acetaminophen and p-cresol as model drug molecules

In this work, the synthesis, characterization, and kinetic investigation of the free-radical polymerization of 4-acetylaminobenzene propenoic ester (ABPE) and 4-methylbenzene propenoic ester (MBPE) were studied. The kinetic behaviors of ABPE and MBPE in the polymerization initiated by azobisisobutyronitrile in dimethylformamide solutions at temperatures between 50 and 120 degrees C were investigated, and experimental and theoretical conversion-time Curves were compared. Both monomers showed a polymerization ceiling temperature (T-c). T-c was calculated with experimental values of k(p)/k(f)(1/2) with a constant concentration of 0.7 mol/L for monomers. T-c was about 141 and 131 degrees C for ABPE and MBPE, respectively. In addition, the solvent effect on the polymerization reaction was investigated via the calculation of the solvent chain-transfer constant (C-s) for the ABPE monomer. Then, C-s was determined from the average degree of polymerization measured with gel permeation chromatography and the calculation of the overall rate of polymerization at 60 degrees C. The results showed that dimethylformamide as a solvent had no effect on the rate of polymerization. (c) 2006 Wiley Periodicals, Inc.