Chapter 2
The components of a crude oil soluble in paraffinic hydrocarbons such as
n-pentane or n-heptane are referred to as the maltenes. They contain three
different types of compounds: saturates, aromatics and resins (SAR). Resins can
be separated from saturates and aromatics through chromatographic methods.
Resins and asphaltenes have similarities in chemical structure and resins play a
key role in the solubilization of asphaltene aggregates in crude oil. They are
thought to solvate the edges of the aromatic clusters of asphaltene colloids [25].
Asphaltene
aggregate
Figure 2.6 Schematic of asphaltenes aggregation 121
Naphthenic acids are carboxylic acids exhibiting aliphatic rings of 5-6 carbon
atoms. They are surface-active when the corresponding salt (naphthenate) is
formed after the ionization of the carboxylic group. Naphthenates can be
considered as a sub-class of resins and may play a role in the stabilization of
asphaltene aggregates [26].
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