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 well pronounced. The high-boiling fractions of petroleum (and this may commence with the saturates fraction 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.
