The infra-red spectra of three Chinese vacuum residua and their SARA f
ractions, together with their average chemical structure parameters ob
tained from elementary analyses, molecular weight determination and H-
1 NMR measurement, have been employed to elucidate, to some extent, ho
w the colloidally dispersed mixed asphaltenes-heavier resins clusters
in the three typical Chinese petroleum vacuum residua, Daqing, Shengli
and Gudao vacuum residua, are formed. It has been concluded that form
ation of the mixed clusters arises from the aromaticity-promoted hydro
gen bonding interaction. (C) 1997 Elsevier Science Ltd.