Ion-exchange, coordination, and adsorption chromatographic separation of heavy-end petroleum distillates.
Information about the composition of heavy-end petroleum distillates is needed because of the increased use of this material as an energy source. The complexity of the heavy ends requires extensive separation to give fractions amenable to compositional studies. A separation scheme is described that separates heavy-end petroleum distillates into acid, base, neutral-nitrogen, saturate, and aromatic fractions. The analytical techniques used include anion- and cation-exchange chromatography, coordination chromatography, and adsorption chromatography. The scheme has been applied to heavy-end distillates from a variety of crude oils having different compositional characteristics. Data from mass spectral analysis of the saturate and aromatic fractions are presented.