Microcalorimetry Study of the Adsorption of Asphaltenes
and Asphaltene Model Compounds at the Liquid–Solid Surface
Diego Pradilla
Sreedhar Subramanian
Sébastien Simon
Johan Sjöblom
Isabelle Beurroies
Renaud Denoyel
10.1021/acs.langmuir.6b00816.s001
https://acs.figshare.com/articles/journal_contribution/Microcalorimetry_Study_of_the_Adsorption_of_Asphaltenes_and_Asphaltene_Model_Compounds_at_the_Liquid_Solid_Surface/3481745
The
adsorption of an acidic polyaromatic asphaltene model compound
(C5PeC11) and indigenous C<sub>6</sub>-asphaltenes onto the liquid–solid
surface is studied. Model compound C5PeC11 exhibits a similar type
of adsorption with a plateau adsorbed amount as C<sub>6</sub>-asphaltenes
onto three surfaces (silica, calcite, and stainless steel). Model
compound BisAC11, with aliphatic end groups and no acidic functionality,
does not adsorb at the liquid–silica surface, indicating the
importance of polar interactions on adsorption. The values of the
adsorption enthalpy characterized by the Δ<i>H</i><sub><i>z</i></sub> parameter (the enthalpy at zero coverage)
indicate that the type of adsorption and the driving force depend
on the surface, a key feature when discussing asphaltene deposition.
The adsorption of C5PeC11 onto silica is shown to be driven primarily
by H bonding (Δ<i>H</i><sub><i>z</i></sub> = −34.9 kJ/mol), unlike adsorption onto calcite where polar
van der Waals and acidic/basic interactions are thought to be predominant
(Δ<i>H</i><sub><i>z</i></sub> = −23.5
kJ/mol). Interactions between C5PeC11 and stainless steel are found
to be weak (Δ<i>H</i><sub><i>z</i></sub> = −7.7 kJ/mol). Comparing C<sub>6</sub>-asphaltenes and their
esterified counterpart shows that adsorption at the liquid–solid
surface is not influenced by the formation of H bonds. This was evidenced
by the similar adsorbed amounts obtained. Finally, C5PeC11 captures,
to a certain extent, the adsorption interactions of asphaltenes present
at the calcite–oil and stainless steel–oil surfaces.
2016-06-27 00:00:00
Model compound C 5PeC exhibits
van der Waals
Asphaltene Model Compounds
aliphatic end groups
acidic polyaromatic asphaltene model compound
C 5PeC
surface
C 6
adsorption
Δ H z parameter