QUALITATIVE AND QUANTITATIVE FUNCTIONAL DETERMINATION IN BITUMEN ACIDIC FRACTIONS BY SI-29 NMR-SPECTROSCOPY - CORRELATION WITH BITUMEN AGING

Knowledge of the chemical functions existing in bitumens represents an important step in the characterization of their aging processes. A ne w investigation method based on a combination of precipitation and IEC separations followed by both qualitative and quantitative Si-29-NMR s pectrocopy is presented. This method is proved to be an efficient proc edure for the determination of the acidic fractions of these high-boil ing petroleum fractions. It has been demonstrated that phenols, carbox ylic acids, and other oxygenated functions were present. A correlation between the acidic character and the aging of bitumens is presented a s a prediction of the rate of evolution of these materials.