STRUCTURAL-ANALYSIS OF THE ASPHALTENE FRACTION OF AN ARABIAN MIXTURE BY A RUTHENIUM-ION-CATALYZED OXIDATION REACTION

Ruthenium-ion-catalyzed oxidation (RICO) was used to investigate the s tructural details of an asphaltene sample. The oxidation products cons isted of homologous series of straight- and branched-chain monocarboxy lic acids, dominated by C-2-C-4 acids. Aliphatic di- and polycarboxyli c acids were also resolved, confirming the presence of polymethylene m oieties linking two or more aromatic units. The detection of ethanedio ic acid among the oxidation products indicates the importance of biary l linkages within the asphaltene. Large amounts:of a polymeric aliphat ic fraction were also recovered after RICO reaction. The recovery of b enzene polycarboxylic acids and a high molecular weight aromatic acid fraction, along with NMR analyses of the original asphaltene, indicate s that the asphaltene molecule is comprised of relatively large polyco ndensed aromatics and hydroaromatic units.