CHARACTERIZATION OF HEAVY RESIDUUM BY A SMALL-ANGLE X-RAY-SCATTERING TECHNIQUE

Small angle X-ray scattering from asphaltene colloids dispersed in heavy petroleum residuum and in liquefied coal has been studied. The results of this study indicate that the asphaltenes from Jobo atmospheric resid have a radius of gyration of about 25 Å and exhibit the same size in all the solvents in which they were dissolved, the size being independent of concentration. It is concluded that the basic unit of the Jobo asphaltenes is a macromolecule having the above size. The colloidal size of the lower molecular weight bituminous coal asphaltene appears to be below the resolution of the small angle X-ray scattering unit presently employed, ca. 10 Å. Tia Juana asphaltenes show the expected variation of particle size with better solvents giving smaller particles. © 1979, American Chemical Society. All rights reserved.