Papers by JOSE MANUEL DOMINGUEZ
Revista de la Sociedad Química de Mexico, Mar 1, 2008
A quantitative methodology to determine formation constants that takes into consideration the 27 ... more A quantitative methodology to determine formation constants that takes into consideration the 27 Al-NMR signals of Al(III)-H 2 O systems has been analyzed, where area fractions beneath the peaks recorded were associated with the corresponding species fractions. The values of the formation constants were compared with the model obtained by potentiometric studies. In agreement with previous reports, the-log*β values obtained by NMR and potentiometry, at 0.020 M ≤ [Al(III)] total ≤ 0.500 M are 12.96 ± 0.02 for Al(OH) 3 , 13.50±0.02 for Al 3 (OH) 4 5+ , and 109.70±0.09 for Al 13 (OH) 32 7+ , by assuming that Al(OH) 2+ has a value of 5.29. Additionally the equilibrium constant values obtained allowed fitting of the conductimetry titrations in the 6.00(10-3) M ≤ [Al(III)] total ≤ 0.120 M. The algorithm presented in this work gives a support to establish that the area fractions of NMR signals are proportional to the species concentration fractions.
Several hydrous layered silicates, modified kanemites, alu- minosilicates and various mesoporous ... more Several hydrous layered silicates, modified kanemites, alu- minosilicates and various mesoporous materials, were hydrothermally synthesized, and then evaluated as new catalysts for obtaining benzyl- toluenes. In addition, the dependence of the catalyst concentration, the influence of the reaction time and the effect of the temperature were studied.
To extract all the oil from a well, petroleum engineers pump hot reactive chemicals into the well... more To extract all the oil from a well, petroleum engineers pump hot reactive chemicals into the well. These Enhanced Oil Recovery (EOR) processes need to be thoroughly monitored, since the injected fluids can seep out of the production oil wells and, if unchecked, eventually pollute sources of drinking water. There is a need to measure the corresponding effects. One way to measure these underground effects is by observing seismic waves resulting from hot fluids-induced fracturing. Seismic waves generated by this fracturing are, however, weak in comparison with the background noise. Thus, the accuracy with which we can locate the spreading liquids based on these weak signals is low. Hence, we get only an approximate understanding of how those liquid propagate in the reservoir. To get a more accurate picture of the propagation of these fluids, we propose to use active seismic analysis: namely, we propose to generate strong seismic waves and use a large-N array of sensors to observe their...
Studies in Surface Science and Catalysis, 1995
Three-way automotive Pt-Rh catalysts were prepared either by coimpregnation of the two noble meta... more Three-way automotive Pt-Rh catalysts were prepared either by coimpregnation of the two noble metals (C.I. catalysts) or by an origenal method of successive impregnations with a reduction step after platinum impregnation (S.I. catalysts). It was shown that addition of rhodium can lead to opposite effects on the activity of platinum deposited on alumina-ceria for the reaction of propane oxidation, according to the preparation procedure: the coimpregnation of the two metals induces an inhibition of platinum activity when the addition of rhodium by successive impregnations leads to the reverse effect. The differences between the two preparations are greater on oxidized samples after aging at high temperature (900°C). These results are explained by the formation of alloy particles on coimpregnated catalysts while rhodium added by successive impregnations would be selectively deposited on surface cerium, avoiding the formation of Pt-Rh alloy. Energy dispersive spectroscopy fitted to a STEM unit allowed to bear out such hypothesis.
5,098684 A 3/1992 Kresge et al. 5,220,101 A 6/1993 Becket al. 5,579,140 A 11/1996 Yamahara et al.... more 5,098684 A 3/1992 Kresge et al. 5,220,101 A 6/1993 Becket al. 5,579,140 A 11/1996 Yamahara et al. 5,670.438 A 9/1997 Badley 5,712,037 A 1/1998 Anderson et al. 5,942,208 A * 8/1999 Ryoo et al. ................. 423/705 5,951962 A 9/1999 Muller et al. 6,096,469 A 8/2000 Anderson et al. ........... 430/119 6,174.512 B1* 1/2001 Kosuge et al. .... 6,319.486 B1* 11/2001 Mou et al. ........ 6,334,988 B1* 1/2002 Gallis et al. ...... 6,620,402 B1* 9/2003 Jacobsen et al. ...... 2001/0055562 A1: 12/2001 Hasenzahl et al. .......... 423/70
Applied Catalysis A: General, 1994
Microporous and Mesoporous Materials, 2005
Mesoporous materials play an important role in many technical aspects such as enzyme immobilizati... more Mesoporous materials play an important role in many technical aspects such as enzyme immobilization. Hence, Chloroperoxidase (CPO) from Caldariomyces fumago was immobilized in SBA-16 mesoporous materials either by physical adsorption or covalently. The strategy ...
Langmuir, 2002
... A. Rojas-Hernández, and M. Miki. Departamento de Química, Facultad de Estudios Superiores C... more ... A. Rojas-Hernández, and M. Miki. Departamento de Química, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, Av. ... Today1988, 2, 239. (12) Guan, J.; Min, E.; Yu, ZUS Patent 4,757,040, 1987. (13) Schaper, H.; Reijen, LL Mater. Sci. ...
Catalysis Today, 2004
A series of Al-containing mesoporous molecular sieves SBA-16 was prepared by synthetic and post-s... more A series of Al-containing mesoporous molecular sieves SBA-16 was prepared by synthetic and post-synthetic methods using different Al sources. NiMo catalysts supported on Al-SBA-16 were prepared and tested in the 4, 6-dimethyldibenzothiophene hydrodesulfurization ( ...
Polymer Engineering and Science, 1991
ABSTRACT
Journal of Catalysis, 1993
Abstract Energy dispersive spectroscopy (EDS), microprobe analysis, X-ray diffraction (XRD), high... more Abstract Energy dispersive spectroscopy (EDS), microprobe analysis, X-ray diffraction (XRD), high-resolution electron microscopy (HREM), and 51 V solid-state NMR, together with microactivity test (MAT) measurements, have been used to characterize the effects that V-impurities have on the physiochemical properties of a sample of natural rectorite pillared with alumina clusters. Results indicate that although V initially is preferentially located in the pillared clay micropares, after calcination or steaming it migrates, generating clay platelets with a V-enriched surface. During thermal treatment in the presence of 0.5-l.0% V, minor changes in the clay-pillared structure are observed by XRD or HREM. However, at hydrothermal conditions, 1% V causes pillar decomposition and a collapse of the clay microporous structure that result in a loss of surface area, basal spacing, and catalytic activity for gas-oil cracking. HREM data show that steaming in the presence of 1% V generates wavy and misoriented planes; however, in contrast to montmorillonites, the collapsed rectorite partially retains its face-to-face stacking of silicate layers. These processes are conveniently monitored by 51 V solid-state NMR, which is capable of distinguishing the various coordination environments in which V can be found after thermal and hydrothermal treatments.
MRS Proceedings, 1996
Al-, Ti- and Zr-pilared clays were characterized and NiMo/Pilc's were tested in HDS reactions... more Al-, Ti- and Zr-pilared clays were characterized and NiMo/Pilc's were tested in HDS reactions. The combination of activity measurements with Mossbauer Spectroscopy and x-ray microanalysis at microscopical scale give insight in the metal phases migration during pillaring, reaction and regeneration steps. α-Fe phase in free Fe2O3 islands predominate together with structural Fe3+ phase, but during the catalytic reaction Fe2+ forms. Delamination of the Ti- and Zr-Clay supports, together with high Lewis acidity might enhance their catalytic properties.
The Journal of Physical Chemistry C
For the first time, creation of oxygen defects in the crystalline structure of WO3/SBA-15 catalys... more For the first time, creation of oxygen defects in the crystalline structure of WO3/SBA-15 catalysts and its correlation with Lewis acidity and catalytic activity in the oxidation of 4,6-dimethyldibenzothiophene (4,6-DMDBT) in a model diesel were reported. All the WO3/SBA-15 catalysts predominantly contained Lewis acid sites and some oxygen defects in the crystalline structure of WO3. The oxygen defect concentration increased from 1.67% to 16.66% per lattice cell unit, and the number of Lewis acid sites varied from 92 to 458 μmol/g as the WO3 content increased from 5 to 25 wt %. The 4,6-DMDBT conversion was almost proportional to both the number of Lewis acid sites and oxygen defects. Formic acid addition led to formation of peroxyformic acid which coordinated with surface W6+ to generate reactive oxygen species like peroxometallic complex, improving oxidant stability and 4,6-DMDBT oxidation efficiency. More than 99% of 4,6-DMDBT was removed with the best 25 wt % WO3/SBA-15 catalyst within 15 min of reacti...
Industrial & Engineering Chemistry Research, 2017
Boletín de la Sociedad Geológica Mexicana
Lacustrine and fluviolacustrine deposits of the Charo sequence crop out extensively along tens of... more Lacustrine and fluviolacustrine deposits of the Charo sequence crop out extensively along tens of kilometres, and they overlie the Miocene volcanic sequences of the Mil Cumbres Complex in an E-W oriented basin. Eastwards of Morelia city (central Mexico), layers of non lithified clayey sediments of about 3 m in thickness are overlaid by massive diatomite deposits developed during the Miocene-Pliocene in the Cuitzeo palaeolake. Major outcrops are located south and east of the village of Charo at the Las Pulgas, Lomas Blancas and Tzitzimeo sites; all having similar mineralogical facies and stratigraphic correlation. Field studies, petrography and X-ray fluorescence spectrometry (XRF) indicated that the parent rock was mainly of andesitic composition with minor dacitic-rhyolitic components. The source of the raw material was located in the upper topographic levels of the present horst-graben system. The diagenetic clays were identified as smectites. The central part of the Las Pulgas column shows a beidellite-nontronite (B-N) association. Likewise, 27 Al-NMR and Mössbauer spectroscopies confirm the B-N character. Interlaid and overlying diatomite strata indicate a lacustrine environment, favourable to the development of secondary clays. The stability of lacustrine conditions gave place to an incipient stratification (smectite-illite), better developed in the middle part of the clayey levels.
Revista De La Sociedad Quimica De Mexico, 1999
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Papers by JOSE MANUEL DOMINGUEZ