Examinando por Autor "Tenorio, Maria Jose"

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Oil acidity reduction by extraction with imidazolium ionic liquids: Experimental, COSMO description and reutilization study
(Elsevier, 2021) Coto, Baudilio; Suarez, Inmaculada; Tenorio, Maria Jose; Nieto, Sandra; Alvarez, Nieves; Peña, Jose Luis
is a main problem because causes high corrosion rates and fouling during refining process. Reduction of crude oil TAN by means of ionic liquids (ILs) can be due to neutralization (basic ILs) or to extraction (ILs acting as solvent). In this work, a synthetic crude oil (SC, 150 g/mol, TAN equal to 3.8) was treated with [EMIm][EtSO4], [EMIm][SCN], and [EMIm][Cl] in the temperature range 30–120 °C and IL/crude ratio in the range 0.03–1 g/g. TAN reductions were up to 50% at high temperature and IL/SC ratio. Water washing and reuse of [EMIm][SCN] were studied. No structural changes were detected but IL TAN increased and reduced the extraction efficiency, probably due to the strong interaction between IL and acid that makes washing with water not completely efficient. However, the reduction in extraction efficiency was much faster for IL without any treatment and such reuse is not possible. The COSMO-RS model was used for the ILs characterization through the σ-profile and was successfully included in the simultaneous correlation of all the experimental data. COSMO-Therm was used to study the liquidliquid equilibria and the predictions of the TAN of the organic phase were in fair agreement with the experimental results. However, COSMO-RS was unable to predict the effect of temperature and described a decrease in TAN reduction as temperature increases. Reuse of IL was also modelled with COSMO-RS and the decrease in extraction efficiency was correctly described related to the IL acid content.
Thiol group functionalization of mesoporous SiO2 SBA-15 using supercritical CO2
(Elsevier, 2018) Tenorio, Maria Jose; Morere, Jacobo; Carnerero, Cyntia; Torralvo, Maria Jose; Pando, Concepcion; Cabañas, Albertina
Chemical modification of mesoporous SiO2 SBA-15 with thiol groups was performed using mercaptopropyltrimethoxysilane (MPTMS) dissolved in supercritical CO2 (scCO2). Thiol groups serve as adsorbents for the selective removal of contaminant metal cations and in catalysis. Functionalization was carried out in scCO2 at temperatures ranging from 40 to 150 C and pressures from 15.0 to 29.0 MPa. For comparison purposes, the reaction was also performed in toluene at 80 and 110 C. As opposed to toluene, scCO2 is considered a green solvent. Grafting of the thiol groups was confirmed by FTIR spectroscopy, thermogravimetric analysis (TGA) and elemental analysis. Grafting density and surface coverage of the materials modified using scCO2 increased with temperature, CO2 density, time and stirring and varied from 1.3 to 4.4 mmol/ g and from 1.3 to 4.0 molecules/ nm, respectively. On the other hand, surface area and pore size decreased as grafting density increased. At temperatures of 80 C or higher, the pore size remained constant, suggesting the formation of a compact monolayer. Modification at higher temperatures led to larger grafting densities but very low surface areas. Assuming total hydrolysis and condensation of the precursor, the optimum grafting density and surface coverage of 2.3 mmol/ g and 2.4 molecules/ nm, respectively, were obtained in scCO2 at 80 C and 25.0 MPa for 4 h. Grafting densities of the samples prepared in toluene were by far much lower than those obtained using scCO2 at lower temperatures and shorter times, which demonstrates the advantages of CO2 as a green functionalization medium.