Acoustic studies of ternary mixture phenanthrene –toluene – heptane as a model of natural flocculating system

Complexity of natural systems causes that results of experimental studies are often ambiguous and extremely unrewarding in interpretation. To overcome this difficulty, relative simple model systems may be investigated in order to provide physical grounds for further discussion. This study deals with adiabatic compressibility of liquid ternary system consisting of phenanthrene, toluene and heptane. Increase of heptane concentration in the mixture changes considerably the partial compressibility of phenanthrene, from common positive value in pure toluene up to clearly negative ones. This is most probably because of selfassociation of phenanthrene due to strong London forces. Heptane seems to promote the self-association. These feature of the investigated system suggests its usefulness in studies of flocculation of asphaltenes from crude oils.