Entity

Time filter

Source Type


Flores-Sandoval C.A.,Mexican Institute of Petroleum | Godinez-Salomon F.,Mexican Institute of Petroleum | Hallen-Lopez J.M.,Escuela Superior de Ingenieria Quimica e Industrias Extractivas | Beltran H.I.,Metropolitan Autonomous University | And 3 more authors.
Asian Journal of Chemistry | Year: 2012

Bis-(aminomethyl)ethers (1-4) have been employed as molecular scavengers for cyanides. They are theoretically studied herein at DFT, thus enabling a theoretical study in order to elucidate why the efficiency as scavenger depends on the substituent placed at the nitrogen atom. The local softness (s +) value for C2 from electrostatic potential analysis (ESP) shows that the following decreasing order of reactivity is in accordance with the experimental yield values: 4, 1, 2 and 3. 1290 runs considering four to ten parameters such as N3-C2 and C2-O1 bond lengths, HOMO and LUMO energies, GAP, dipolar moment, partition coefficient, atomic charge, local softness, global hardness, electronegativity and 13C NMR chemical shift were taken into account in a structure-activity relationship study. In particular five runs of linear combination of four (run 259), five (run 517), seven (runs 937 and 1063) and eight (run 1214) molecular indexes have shown the best F values, being the run 517, which present the highest F value 4 to 10 parameters. Source


Estudillo-Wong L.A.,Laboratorio Of Electroquimica Y Corrosion | Vargas-Gomez A.M.,Laboratorio Of Electroquimica Y Corrosion | Arce-Estrada E.M.,Escuela Superior de Ingenieria Quimica e Industrias Extractivas | Manzo-Robledo A.,Laboratorio Of Electroquimica Y Corrosion
Electrochimica Acta | Year: 2013

The electro-oxidation of methanol was studied in alkaline solution on Pd nanoparticles supported on carbon black (XC-72R, C) and TiO2/C composite. The materials were prepared via organic colloid route at 170 C with 5 wt% of Pd. X-ray diffraction (XRD), PdO monolayer reduction (PdOred) and CO-stripping was employed to characterize both structure and electrochemical properties. According to this, the lattice parameter decreases from 0.3991 to 0.3905 nm due to a possible formation of Pd-Ti alloy. This modification is linked with the electrochemical active surface area (ECSA) decreasing from 22 to 18 m2 g-1. On the other hand, studies as a function of temperature and alcohol concentration indicated that the current for methanol electro-oxidation is higher and more stable at Pd/TiO2-C, with Ea = 44.042 kJ mol-1. Then, it is highly possible that at Pd/TiO2-C, the OH-/OH ads couple is adsorbed at the TiO2 sites, increasing the kinetic of methanol oxidation reaction at the catalyst surface. © 2013 Published by Elsevier Ltd. Source


Rodriguez-Gonzalez F.,Escuela Superior de Ingenieria Quimica e Industrias Extractivas | Perez-Gonzalez J.,Laboratorio Of Reologia | Marin-Santibanez B.M.,National Polytechnic Institute of Mexico
Revista Mexicana de Ingeniera Qumica | Year: 2011

The knowledge of the flow kinematics of polymer melts is relevant for their processing as well as for the design of molds and dies. However, the analysis of the flow behavior of polymer melts during extrusion has been typically performed by using rheometric measurements and numerical simulation. In this work, a description of the kinematics of a low-density polyethylene flowing under continuous extrusion through a transparent capillary die was performed by using the particle image velocimetry (PIV) technique coupled with rheometric measurements. The velocity maps for the polymer melt exhibited fully developed flow, meanwhile the flow rate data obtained from the velocity profiles agreed very well with the rheometric ones. The maximum difference in the volumetric flow rates by using the two methods was 6.5%, which shows the reliability of the PIV technique to describe the flow behavior of the polymer melt. The true flow and viscosity curves for the polymer melt were obtained from the measured wall shear stress and velocity profiles, in a wider shear rate range than the accessible by the capillary measurements, including the transition between the Newtonian and power-law regions. This allowed the viscosity data to be very well fitted by a Carreau constitutive equation. Source


Estudillo-Wong L.A.,Laboratorio Of Electroquimica Y Corrosion | Arce-Estrada E.M.,Escuela Superior de Ingenieria Quimica e Industrias Extractivas | Manzo-Robledo A.,Laboratorio Of Electroquimica Y Corrosion
Electrochimica Acta | Year: 2014

The electroreduction of nitric oxide (NO) in alkaline media was carried out on Pt nanoparticles (5 wt.% Pt), which were synthesized by the carbonyl route. The as-prepared materials were supported on Carbon Black (XC-72R, C) and TiO2-C composite (10 wt.% TiO2) and deposited on glassy carbon (GC) electrode. X-ray Diffraction (XRD), CO-stripping and hydrogen adsorption-desorption (Hupd) analysis were employed to characterize the structure and electrochemical properties. According to XRD patterns, the particle size increases from 3.95 to 8.98 nm due to the interaction of Pt with TiO2 in the carbon matrix. This modification promotes a better performance during CO-oxidation and proton adsorption-desorption. As a consequence, the performance toward NO-reduction was more important in TiO 2-C composite, linked with the electrochemical active-surface area and chemical surface area relationship (ECSA/CSA). It was found that the mechanism for the reduction of nitric oxide toward nitrogen is a bi-functional process with coupled chemical and electrochemical interfacial-reactions with NH2 specie as intermediate, as demonstrated by the induced reduction reaction of NO2 - and NO2 - + NO, and UV-vis spectrometry. © 2014 Elsevier Ltd. Source


Estudillo-Wong L.A.,Laboratorio Of Electroquimica Y Corrosion | Santillan-Diaz G.,Laboratorio Of Electroquimica Y Corrosion | Arce-Estrada E.M.,Escuela Superior de Ingenieria Quimica e Industrias Extractivas | Alonso-Vante N.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Manzo-Robledo A.,Laboratorio Of Electroquimica Y Corrosion
Electrochimica Acta | Year: 2013

The electroreduction of nitrogen species in alkaline medium was performed on platinum nanoparticles (1-2 nm) with metal loadings of 5 and 10 wt% Pt, synthesized by the chemical carbonyl route. The electrochemically active surface analysis evidences that the real surface area is concomitant to the Pt-loading in the support. The electrochemical analysis put in evidence that nitrite ions were reduced from -0.6 to -0.78 V and the charge transfer step is attributed to the NO2-/NO redox couple. The Tafel slope analysis confirms that from Ep to -0.78 V the reduction of NO occurs via an ECE mechanism. An analysis of Nicholson-Shain schemes and NO-saturated in solution verified these results. © 2012 Elsevier Ltd. All rights reserved. Source

Discover hidden collaborations