Influence of Ionic Liquids on the Aggregation and Pre-aggregation Phenomena of Asphaltenes in Model Solvent Mixtures by Molecular Dynamics Simulations and Quantum Mechanical Calculations

This work presents a systematic study of asphaltene pre-aggregation phenomena in the absence and presence ionic liquids (ILs) from family 1-alkyl-3-methylimidazolium by molecular dynamics simulations. The effects alkyl chain length cation (studying ILs with chains between C4 C10) dimension anion (testing chloride bromide) on aggregation behavior asphaltenes have been studied. To correlate results obtained direct interaction each additive asphaltene, latter was investigated both analysis radial distribution functions simulations quantum mechanical calculations. DFT method used to calculate relative stability asphaltene-ionic liquid dimers also energy, shape, spatial frontier orbitals. It found that all studied present dispersing effect model solvents, except for mixtures rich toluene where, most cases, opposite is observed. accompanied intensity as measured functions. side radius are subtler, but it seems dispersion increases cation’s decreases anion; these more clearly observed richer n-heptane. These trends were corroborated calculations, which showed energetic asphaltene-additive dimer higher longer smaller. Pre-aggregation containing CO2, proved be precipitating agent experimentally. performances IL not altered CO2.