Sulfur compounds in high-boiling fractions of saudi arabian crude oil

This study describes the isolation and characterization of sulfur compound types in high boiling distillate of Arab crude oil. The distillates were prepared by physical and chemical methods like adsorption chromatography and complexation with mercurous nitrate and iodine. Spectrophotometric methods were used for detection and. identification. The sulfur compound types, thus obtained, were classified into aliphatic sulfides, aromatic sulfides, and thiophenes. Sulfides represented the most abundant type of sulfur compounds in the distillate. The 225-500°C boiling range distillate was fractionated into four distillate cuts using molecular distillation and each cut was further separated into three chromatographic fractions, saturated hydrocarbons, aromatic hydrocarbons, and sulfur concentrates by using liquid solid adsorption chromatography on a dual packed (silica-alumina) column. The chromatographic separation was effectively monitored by measurement of refractive index, ultraviolet spectroscopy, infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The complex aromatic sulfur concentrates were analyzed by gas chromatography using flame photometric and flame ionization detector, infrared spectroscopy, and gas chromatography - mass spectrometry. Benzothiophenes, dibenzothiophenes, naphthobenzothiophenes and homologs are found to be the major sulfur compound types in the distillate fractions.