Determination of Hansen Solubility Parameters of Asphaltene Model Compounds

The Hansen solubility parameters (HSPs) of asphaltene model compounds were determined experimentally via solubility testing. For the test, we synthesized various archipelago- and continental-type molecule model compounds: 5 were steroid-derived naphthoquinoline compounds; 14 were phenanthrene/pyrene-derived compounds; 2 were nickel porphyrins; and 1 was an alkyl hexabenzocoronene molecule. Some of them contain nitrogen as the quinoline or porphyrin structure, oxygen as the furan structure, and sulfur as the thiophene structure. Using the Hansen sphere method, the HSPs δd, δp, and δh were successfully determined with only small errors, with values of 18.7–21.0, 2.7–8.1, and 2.2–6.5 MPa1/2, respectively. For real asphaltenes, these values were about 19, 4, and 4 MPa1/2, respectively. The solubility characteristics of the model compounds were found to be complex, because there is not clear relationships between solubility and chemical structures. Even slight structural differences, such as the type and location of heteroatoms, greatly changed the Hansen sphere radius, R 0. The HSP analyses will enable the development of a mixing strategy for model compounds, to mimic asphaltene.