Isolation and characterization of petroleum sulfonates

Abstract

Different petroleum fractions were sulfonated with fuming sulfuric acid. The fractions were isolated from Boscan crude oil by Soxhlet extraction. This method allows for the separation of four fractions which were extracted with acetonitrile, methanol, n-heptane and benzene, respectively. The separation was monitored by UV/VIS spectrophotometry AAS. After sulfonation, the oil layer was neutralized with caustic soda. The sulfonated sodium salts of each fraction were extracted with ethanol–water. UV/VIS spectra of the diluted aqueous phases of each fraction showed a characteristic band of sulfonate. In all cases, Fraction 3 showed the greatest concentration of sulfonates. Finally, the molecular mass distribution was examined by using an Ultrastyragel column. Fraction 3 exhibited a widespread molecular mass and symmetrical distribution.