Papers by Joaquin Perez-Pariente
Microporous and Mesoporous Materials, Mar 1, 2005
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Elsevier eBooks, 2005
ABSTRACT Dibenzyldimethylammonium cations containing one fluorine atom in ortho, meta or para pos... more ABSTRACT Dibenzyldimethylammonium cations containing one fluorine atom in ortho, meta or para position of both aromatic rings have been used as structure directing agents for the synthesis of AFI-type materials. The presence of fluorine improves the templating ability of the molecule, as compared with the all-hydrogen counterpart. A computational study of the interaction between the different cations and the AFI framework has been carried out to explain the experimental results in terms of the packing efficiency and interaction energies of the molecules inside the channels. The silicon environments in SAPO-5 have been found to be dependent upon the specific template molecule used in the synthesis.
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Microporous and Mesoporous Materials, Apr 1, 2010
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Studies in Surface Science and Catalysis, 2005
ABSTRACT The 1-benzyl-1-methyl-hexamethylenammonium (BMHM) cation under the appropriate synthesis... more ABSTRACT The 1-benzyl-1-methyl-hexamethylenammonium (BMHM) cation under the appropriate synthesis conditions is a good structure directing agent (SDA) for the synthesis of pure silica zeolite beta in fluoride media. The chemical properties of this cation change with the replacement of a fluorine atom by a hydrogen atom in the aromatic ring and the nature and morphology of the crystal phases thus obtained are affected. The 1-orthofluorobenzyl-1-methyl- hexamethylenammonium allows the crystallization of all-silica beta zeolite but the morphology of crystals is very different from that of beta obtained with the all-hydrogen counterpart. The meta-F derivative leads to a mixture of three phases, Beta, nonasil (NON) and a characteristic unidentified phase, whereas by using the para-F cation only nonasil is obtained.
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Zeolites, Apr 1, 1992
... Spain j. Pdrez-Pariente, A. Mifsud, and T. Blasco Instituto de Tecnologia Qulmica, CSIC-UPV, ... more ... Spain j. Pdrez-Pariente, A. Mifsud, and T. Blasco Instituto de Tecnologia Qulmica, CSIC-UPV, Universidad Politdcnica de Valencia, Valen-cia, Spain j. Sanz Instituto de ... 1988, 92, 3965 17 Goepper, M., Guth, F., Delmotte, L. and Kessler, H., in Zeo/ites: Facts, Figures, Future, (Eds ...
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Microporous and Mesoporous Materials, Mar 1, 2007
A new chiral structure directing agent, (S)-(−)-N-benzylpyrrolidine-2-methanol, has been rational... more A new chiral structure directing agent, (S)-(−)-N-benzylpyrrolidine-2-methanol, has been rationally designed, synthesized and successfully used to direct the crystallization of the AFI-type structure in various compositions. AlPO-5, SAPO-5, MgAPO-5, VAPO-5, CoAPO-5 and ZnAPO-5 materials have been obtained and characterized by several physico-chemical techniques. Characterization results demonstrated the incorporation of the different dopants within the microporous network, giving place to materials
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Elsevier eBooks, 2004
AlPO and SAPO materials have been synthesised from gels containing N-benzyl cyclic amines as stru... more AlPO and SAPO materials have been synthesised from gels containing N-benzyl cyclic amines as structure directing agents (SDA). The nature of the crystalline phases, their degree of crystallinity, crystal size and morphology and Si incorporation can be modified by tuning the ring size of the cyclic amine.
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ChemInform, Aug 16, 2005
For Abstract see ChemInform Abstract in Full Text.
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New Journal of Chemistry, 2016
Zeolite A synthesized from Ethiopian raw kaolin via alkali fusion with 91% crystallinity and CEC ... more Zeolite A synthesized from Ethiopian raw kaolin via alkali fusion with 91% crystallinity and CEC of >310 mg CaCO3 per g.
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Separation and Purification Technology, 2016
Abstract Fluoride contamination of drinking water is a serious problem in the Rift Valley region ... more Abstract Fluoride contamination of drinking water is a serious problem in the Rift Valley region of Ethiopia. In this work, a nano-hydroxyapatite/stilbite (nHAST) composite was prepared based on locally available stilbite zeolites and its fluoride removal performance was compared with that of Bone Char (BC). The reaction mechanism involving the fluoride adsorption is analyzed based on kinetics and isotherm studies. In both nHAST and BC the kinetic data fitted well to a pseudo-second order kinetic model of similar characteristics. In contrast, the adsorption isotherm on the nHAST composite fitted best with the Freundlich model, whereas on BC, it correlated well with the Langmuir model, suggesting a different mechanism: adsorption of fluoride on BC was homogeneous, whereas on the composite was heterogeneous, possibly related to the higher load of fluoride on the hydroxyapatite component in the composite. At low concentrations, both adsorbents behave similarly; however, the maximum adsorption capacity, measured at high concentrations, is higher in the nHAST composite than in BC. The intrinsic HAp capacity of nHAST, normalized to the amount of HAp on the adsorbent, is significantly higher (9.15 mg F − /gHAp) than that of BC (1.08 mg F − /gHAp) (measured at low F − initial concentrations where the OH/F-exchange mechanism predominates), showing a much higher F − removal efficiency of HAp on the composite. These results foresee a high potential of nHAST composite toward F − removal implementation, specially taking into account the low-cost, ease of production, local availability and social acceptance.
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Journal of Catalysis, Jul 1, 2000
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Chemistry of Materials, Oct 23, 2007
Hydrothermal synthesis of zeolites often requires the presence of an organic molecule or structur... more Hydrothermal synthesis of zeolites often requires the presence of an organic molecule or structure directing agent (SDA), which participates in the organization of the inorganic tetrahedral units into a particular topology. Bulky molecules are frequently employed as SDAs in attempts ...
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Microporous and Mesoporous Materials, Aug 1, 2010
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Studies in Surface Science and Catalysis, 2002
ABSTRACT
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ChemInform, Aug 17, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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Elsevier eBooks, 2002
... using CuK~ radiation, on a Seifert XRD 3000P diffractometer operating at low angle (20 from 1... more ... using CuK~ radiation, on a Seifert XRD 3000P diffractometer operating at low angle (20 from 1 to 10~ For the TEM studies the samples were dispersed in acetone and dropped on a holey carbon copper microgrid. ... 4. REFERENCES 1. SL Burkett, SD Sims, S. Mann, Chem. ...
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Microporous and Mesoporous Materials, Feb 1, 2006
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Journal of Catalysis, 1998
ABSTRACT High silica content SAPO-5 was synthesized using aqueous and two-liquid phase systems in... more ABSTRACT High silica content SAPO-5 was synthesized using aqueous and two-liquid phase systems in presence of hexadecyltrimethylammonium bromide. The scope of the work was to study the effect of the synthesis parameters on the amount of silicon incorporated into the network, the different silicon environments and on the catalytic activity in them-xylene isomerization. The results showed that the use of the two-liquid phase synthesis causes greater incorporation and diversification of the silicon distribution in the SAPO-5 network and therefore, a substantial increase in the material acidity. The maximum catalytic activity in the conversion of meta-xylene was achieved by the samples synthesized via the two-liquid phase method and in the presence of the surfactant with 10 wt% of SiO2. Silica incorporation above 10% creates greater silicon domains, reducing drastically the catalytic activity of the material.
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Microporous and Mesoporous Materials, May 1, 2005
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Journal of the American Chemical Society, Dec 1, 1993
ABSTRACT
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Papers by Joaquin Perez-Pariente