X-RAY DIFFRACTION OF ASHALTENES: WHAT CAN IT TELL US?

摘要

The stacking of asphaltenes has been inferred from X-ray diffraction of solid asphaltenes. The diffractograms reveal normally three different broad peaks where the "stacking" is related to the 002 peak which is seen sometimes as a shoulder on a peak related to alkyl ordering. The literature is reveiwed and new data investigating not only heptane asphaltenes but fractions obtained in toluene-heptane mixtures are reported. The diffractograms are compared with other information on the compositional changes in the fractions to see if similar results can be deduced. The paper will based on these findings discuss if the solid state can at all be related to the state when asphaltenes are dissolved.