Three analytical methods to isolate and characterize vanadium and nickel porphyrins from heavy crude oil

Three extraction methods to isolate metalloporphyrins from a heavy crude oil have been developed. The metalloporphyrins were isolated from Boscan crude oil by (a) SARA method, (b) Soxhlet extraction method, and (c) vacuum sublimation method. Each fraction was characterized by UV-visible and atomic absorption spectroscopy. SARA method allowed the separation of hydrocarbon group types which usually cover saturates, aromatics, resins and asphaltenes. Soxhlet extraction method resulted in more effective, quick and inexpensive method to isolate these metalloporphyrins. Finally, vacuum sublimation method allowed the separation of volatile or low molecular weight metalloporphyrins. (C) 1999 Elsevier Science B.V. All rights reserved.