Mexican Institute of Petroleum

About: Mexican Institute of Petroleum is a government organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Catalysis & Asphaltene. The organization has 3273 authors who have published 4170 publications receiving 87269 citations.

Molecular mechanics and microcalorimetric investigations of the effects of molecular water on the aggregation of asphaltenes in solutions

Abstract: The interaction of two model asphaltene molecules from the Athabasca sand oil with a water molecule in a toluene solution was studied by means of molecular mechanics calculations. It was found that water forms bridging H bonds between the heteroatoms of asphaltenes with a considerable span in energies. The stronger H bond found has energies higher than those corresponding to the stacking of the aromatic areas of the same asphaltene molecules. This shows that the water molecule may generate additional mechanisms of aggregation of asphaltenes in toluene solution, as found experimentally. The H bond mechanism depends on the heteroatoms involved, the extension of the aromatic regions, and the steric interference present in the asphaltene molecules. The simulation results have been compared with experimental values of enthalpy of association of two different petroleum asphaltenes obtained by titration calorimetry. A simple dimer dissociation model was used to derive the information about the heat and the const...

WOx/TiO2 Catalysts via Titania Nanotubes for the Oxidation of Dibenzothiophene

Abstract: WOx/TiO2 catalysts were synthesized by impregnating aqueous (NH4)2WO4 on hydrous titania nanotubes. The materials were annealed in air at 500 °C and characterized by X-ray diffraction (XRD), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and X-ray photoelectron spectroscopy (XPS); their catalytic activity was evaluated in the oxidation reaction of dibenzothiophene (DBT). After annealing at 500 °C, the structure of the support transformed from orthorhombic, with nanotubular morphology, to tetragonal, yielding anatase nanoparticles decorated by tungsten nanoparticles on its surface. During this transformation, the nanotubes released residual Na+ ions from the interlayer space, which reacted with tungstate species to change the W coordination from octahedral to tetrahedral, yielding ≤1 nm Nax(WO4) nanoparticles on the surface of anatase TiO2. These nanoparticles were highly active for the DBT ...