Small angle X-ray scattering from coal-derived liquids

Abstract

Small angle X-ray scattering measurements were used to determine the size and shape of asphaltene and preasphaltene micelles in solution. The fraction of the coal-derived liquids forming micelles in solution was as high as 49%. The fraction depends upon the concentration and molecular size of the asphaltenes and preasphaltenes, the [pi]--gp and/or hydrogen bonding properties of the solvent and the agitation. Most systems studied were polydispersed with the majority of the micelles being spherical with a diameter of 22-38 A. Micelles in the 80-100 A range were also apparent but at 5-12% of the number of the smaller size. Variations in the scattering intensity over the scattering angles and the variations of the absolute intensity of scattered X-rays from solutions irradiated immediately after ultrasonic agitation and upon extended sitting, gl118 suggested the presence of a low level floc in most of the solutions.