CHARACTERIZATION OP VANADIUM COMPOUNDS IN SELECTED CRUDES II. ELECTRON PARAMAGNETIC RESONANCE STUDIES OP THE FIRST COORDINATION SPHERES IN PORPHYRIN AND NON-PORPHYRIN FRACTIONS

Abstract

ABSTRACT We applied electron paramagnetic resonance spectroscopy (EPR) to heavy petroleum fractions to characterize the first coordination sphere around the vanadyl +2 ion. The fractions were generated using a modified porphyrin extraction procedure. For the residual oil from the extraction, which contains the non-porphyrin metals, the first coordination sphere was dominated by 4N and N O 2S for Boscan, Beta, Morichal, and Arabian Heavy crudes. Maya had distinctively different parameters. These findings are significant for determining the overall structure of metal-containing compounds in heavy crude oils. We discuss the difference between the porphyrin and non-porphyrin behavior, possible blogenic precursors, and some process implications.