ABSTRACT
As the boiling points of petroleum fractions increase, the complexity of the constituents in
these fractions also increases, and the differences between the main classes of hydrocarbons
become less pronounced. The high-boiling fractions of petroleum (and this may commence
with the saturates and the aromatics fractions, depending on the boiling profile of the crude
oil) may be considered as having an extremely complicated composition. In fact, any
attempted isolation of individual compounds is a frustrating and an impossible task.
