Fractionation of petroleum resins by normal and reverse phase liquid chromatography

Native petroleum resins from two Mexican crude oils have been fractionated using reversed phase chromatography (RPC) and adsorption chromatography normal phase chromatography (NPC). RPC with acetone/DCM and NPC with cyclohexane/DCM/acetone produced different resin fractions that were characterized by Fourier transform infrared (FT-IR) spectroscopy and gel permeation chromatography (GPC). Observable reduction in polydispersity was achieved for the resins with both systems. Chromatographic fractionation permits a more complete inventory of structural features in this kind of complex polar-hydrocarbon mixtures.