NMR Characterization of Size Exclusion Chromatographic Fractions from Asphalt

摘要

Size exclusion chromatography was used to separate an asphalt into nine fractions, and these fractions were then investigated by ~1H and ~(13)C NMR. From the integration of the spectra, various molecular structural parameters were calculated. The aromatic carbon to nitrogen and the aromatic carbon to sulfur ratios were determined for six of the fractions. The catenation (linear and circular) of the aromatic ring structure was determined for six fractions. It appears that circular catenation is more probable for the high molecular weight fraction. For the lower molecular weight fraction, both linear and circular catenation are equally probable.