A computational study on the steric effects of naphthenic moieties on aggregation interactions of nonconventional petroleum constituents

Download
  1. Get@NRC: A computational study on the steric effects of naphthenic moieties on aggregation interactions of nonconventional petroleum constituents (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1002/poc.3329
AuthorSearch for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleJournal of Physical Organic Chemistry
ISSN0894-3230
Volume28
Issue3
Pages234241; # of pages: 8
SubjectAggregates; Aromatic compounds; Aromatic hydrocarbons; Aromatization; Atoms; Computation theory; Density functional theory; Free energy; Gibbs free energy; Hydrogen; Monomers; Oil shale; Oligomers; Aggregation behavior; Aromatic rings; Computational studies; DFT calculation; Dispersion interaction; Interaction enthalpies; Optimized geometries; Steric interactions; Dimers
AbstractNonconventional oil is usually heavy and extra heavy crude or light oil that is relatively unstable. This oil contains varying proportions of larger, more aromatic constituents rather than molecules that can be distilled directly into fuels and petrochemicals. We perform density functional theory (ωB97X-D/6-31G(d,p)) calculations to study the contributions of steric effects and dispersion interactions in a series of dimers and trimers of model hydrocarbons containing fused aromatic and cyclohexyl (referred to in the petroleum literature as naphthenic) rings. The aggregation behavior of these molecules is analyzed in terms of the optimized geometry, atomic charges, interaction enthalpy (ΔH), and Gibbs free energy (ΔG298). The ΔH and ΔG298 values show that all the dimerization and trimerization processes are exothermic, and only a few are spontaneous at 298 K. The naphthenic hydrogen atoms have a key role in the orientation of the monomers in dimer and trimer aggregates. The interaction among naphthenic hydrogen atoms belonging to adjacent monomers causes steric repulsion. The interaction of naphthenic hydrogen atoms with the π-electronic clouds of aromatic rings in adjacent molecules causes attraction. In both cases, the naphthenic hydrogen atoms cause deviation of the monomer from the initial parallel displaced configuration in dimers and trimers. These results reflect the importance of naphthenic rings and their steric interactions in determining the relationship between structures of nonconventional petroleum constituents and their tendency to aggregate and cause fouling.
Publication date
PublisherWiley
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); National Institute for Nanotechnology
Peer reviewedYes
NPARC number21275682
Export citationExport as RIS
Report a correctionReport a correction
Record identifierc87f6f64-74be-4ca7-8181-33dbe521f384
Record created2015-07-14
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)