Characterization of the Structure of Saudi Crude Asphaltenes by X-ray Diffraction

Abstract

Structural characterization studies have been carried out on four commercial Saudi Arabian crude oils. The aromaticity and crystallite parameters of the asphaltenes were studied by X-ray diffraction methods and compared to the average structural parameters calculated from nuclear magnetic resonance spectra.

Investigation of the mechanism of sediment formation in residual oil hydrocracking process through characterization of sediment deposits

“…These substructures are repeatedly joined by short saturated carbon chains forming large polyaromatic hydrocarbon sheets, which are combined in clusters [27][28][29]. Typically, the material posses a remarkable low H/C ratio (<0.6) combined with a very high aromaticity (fa > 0.8).…”

Investigation of structural parameters and self-aggregation of Algerian asphaltenes in organic solvents

“…According to chemical structure, asphaltenes are aromatic polycyclic molecules surrounded and linked by aliphatic chains and heteroatoms (sulfur, nitrogen, oxygen) as well as traces of metal elements like nickel, iron, and vanadium. The chemical composition and structure of single asphaltene molecules can be assessed using different analytical techniques (Calemma et al 1995;Shirokoff et al 1997;Pekerar et al 1999;Bouhadda et al 2000;Buenrostro-Gonzalez et al 2002;Groenzin and Mullins 2000;Ancheyta et al 2002;Ibrahim et al 2003;Khan et al 2003;Avid et al 2004;Acevedo et al 2005;Siskin et al 2006). Elemental analysis, mass spectroscopy, and 1 H NMR can be used for determination of the average structural parameters such as the aromatic carbon ratio, the average number of alkyl side chains, and the degree of peripheral aromatic carbon substitution (Dereppe et al 1978;Dickinson 1980;Daaou et al 2008Daaou et al , 2009).…”

Characterization of asphaltenic material obtained by treating of vacuum residue with different reactive molecules

“…These graphenes are formed by the staging of aromatic molecules present in the asphaltenic structure. There are also possibilities to appear other two peaks at a higher 2h value and that are due to the reflection of first (1 0 0) and second (1 1 0) nearest neighbors in the ring structure [17][18][19][20]. And the peak intensities due to these bands are very…”