Trabajo presentado en la 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, ... more Trabajo presentado en la 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, celebrada en Amantea (Italia) del 14 al 17 de junio de 2015.
Trabajo presentado en la 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, ... more Trabajo presentado en la 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, celebrada en Amantea (Italia) del 14 al 17 de junio de 2015.
Trabajo presentado en la Reunion de la Sociedad Espanola de Catalisis, SECAT'15, celebrada en... more Trabajo presentado en la Reunion de la Sociedad Espanola de Catalisis, SECAT'15, celebrada en Barcelona (Espana) del 13 al 15 de julio de 2015.
Trabajo presentado en la 6th FEZA Conference, celebrada en Leipzig (Alemania) del 08 al 11 de sep... more Trabajo presentado en la 6th FEZA Conference, celebrada en Leipzig (Alemania) del 08 al 11 de septiembre de 2014.
Trabajo presentado en el I Encuentro de Jovenes Investigadores de la Sociedad Espanola de Catalis... more Trabajo presentado en el I Encuentro de Jovenes Investigadores de la Sociedad Espanola de Catalisis (SECAT), celebrado en Malaga (Espana) del 22 al 24 de junio de 2014.
This paper presents the results obtained in the selective esterifieation of glycerol with laurie ... more This paper presents the results obtained in the selective esterifieation of glycerol with laurie acid using zeolites beta as catalysts. The influence of different catalyst parameters (Si/A1 ratio, crystal size, hydrophobicity) on the activity and selectivity of the reaction are discussed.
The Beckmann rearrangement of cyclohexanone oxime (1) was carried out in the liquid phase in the ... more The Beckmann rearrangement of cyclohexanone oxime (1) was carried out in the liquid phase in the presence of a series of acid zeolites (HY-20, HY-50, HY-100, HYD, and HZSM-5) at different reaction temperatures. Together with e-caprolactam (2). 5-cyano-1-pentene (3), and cyclohexanone (4) were present in the reaction mixtures. From the selectivity curves of 2 and 3, it can be concluded that a Ritter equilibrium between 2 and 3 occurs under our experimental conditions, the direction of the process depending strongly on the hydrophobicity of the catalyst. The influence of the level of Na+ exchange and of the framework Si/AI ratio on the total conversion and the selectivity of 2 reveals that medium and strong acid sites (p& < 0) catalyze the reaction. Finally, no appreciable variations in the specific activity of the catalyst were observed when changing from a tridirectional large pore size sample (Y) to a medium pore size (ZSM-5).
Modified mordenites have been used in the direct conversion of glucose into 5-hydroxymethylfurfur... more Modified mordenites have been used in the direct conversion of glucose into 5-hydroxymethylfurfural (5-HMF) in two different media: the ionic liquid 1-butyl-3-methylimidazolium bromide ([BMIM]Br) and a biphasic system composed of water–acetone and ethyl acetate.
This paper reports the results obtained in the synthesis, characterization and catalytic activity... more This paper reports the results obtained in the synthesis, characterization and catalytic activity of thiol-MCM-41 materials synthesized using an improved method of preparation. This novel method of synthesis includes the partial replacement of the surfactant used previously-hexadecyltrimethylammonium bromide, for a shorter chain surfactant such as dodecyltrimethylammonium bromide. It also includes the use of tetramethylammonium hydroxide (TMAOH) as co-structuring agent instead of NaOH. The materials obtained from this modified gels present a higher order in the channels arrangement confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. These materials incorporates an important amount of thiol groups which can be oxidized with H 2 O 2 in order to obtain the corresponding sulfonic groups, with a very strong acidity. The catalysts so obtained have been tested in the esterification of glycerol with fatty acids-oleic and lauric. The results obtained indicate that the catalysts prepared with mixtures of surfactants are more selective to the monoglycerides than the ones synthesized only with hexadecyltrimethylammonium bromide, probably due to the higher order in the channels packing.
SAPO-34 silicoaluminophosphates are well known as catalysts for the synthesis of light olefins–et... more SAPO-34 silicoaluminophosphates are well known as catalysts for the synthesis of light olefins–ethylene and propylene–from methanol by using the methanol to olefins (MTO) process, first described by Mobil. SAPO-18, which has a microporous framework structure related to but crystallographically distinct from SAPO-34, has been much less studied but promises to be a potential catalyst in the MTO process. The main drawback of these catalysts in this reaction is their rapid deactivation, due to the deposition of heavy carbonaceous products–coke–on the surface of the solid avoiding the access of methanol molecules to the active centres located inside the pores of the SAPO catalysts. We have used different mesoporogen agents–nanoparticulate carbons and chitosan–aiming to generate mesoporosity in the SAPO-18 crystals, in an attempt to improve the accessibility of the reagent to the active centres of SAPO-18 and, in that way, inhibit catalyst deactivation. All the materials prepared in this work present similar framework composition and silicon distribution and the main difference among them is the hierarchical porosity generated by the mesoporogen additives use in the synthesis, as determined by STEM. Using chitosan polymer as a secondary template results in an increase of the external surface, which improved significantly the internal diffusivity enhancing the life time of the catalyst in the MTO process.
A series of high-acidity, tailored pore size, MCM-41 catalysts was prepared and tested for the es... more A series of high-acidity, tailored pore size, MCM-41 catalysts was prepared and tested for the esterification of glycerol with stearic acid making use of the spontaneous structure swelling occurring at high temperature hydrothermal synthesis. Optimal conditions for surfactant removal, propylthiol post-synthesis grafting and oxidation were found, leading to final sulphur loadings comparable to those of the materials synthesized by co-condensation. A relevant influence of the pore size on the catalytic performance was found, leading to an optimal size of the porous system which maximized the yield to the desired monostearine.
... Pore-size control of AI-MCM-41 materials by spontaneous swelling Isabel Diaz, Joaquin P6rez-P... more ... Pore-size control of AI-MCM-41 materials by spontaneous swelling Isabel Diaz, Joaquin P6rez-Pariente* and Enrique Sastre Instituto de Cat~disis y Petroleoquimica ... Pore diameter distribution was obtained using argon as adsorbate and following the Horvath-Kawazoe method. ...
Trabajo presentado en la 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, ... more Trabajo presentado en la 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, celebrada en Amantea (Italia) del 14 al 17 de junio de 2015.
Trabajo presentado en la 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, ... more Trabajo presentado en la 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, celebrada en Amantea (Italia) del 14 al 17 de junio de 2015.
Trabajo presentado en la Reunion de la Sociedad Espanola de Catalisis, SECAT'15, celebrada en... more Trabajo presentado en la Reunion de la Sociedad Espanola de Catalisis, SECAT'15, celebrada en Barcelona (Espana) del 13 al 15 de julio de 2015.
Trabajo presentado en la 6th FEZA Conference, celebrada en Leipzig (Alemania) del 08 al 11 de sep... more Trabajo presentado en la 6th FEZA Conference, celebrada en Leipzig (Alemania) del 08 al 11 de septiembre de 2014.
Trabajo presentado en el I Encuentro de Jovenes Investigadores de la Sociedad Espanola de Catalis... more Trabajo presentado en el I Encuentro de Jovenes Investigadores de la Sociedad Espanola de Catalisis (SECAT), celebrado en Malaga (Espana) del 22 al 24 de junio de 2014.
This paper presents the results obtained in the selective esterifieation of glycerol with laurie ... more This paper presents the results obtained in the selective esterifieation of glycerol with laurie acid using zeolites beta as catalysts. The influence of different catalyst parameters (Si/A1 ratio, crystal size, hydrophobicity) on the activity and selectivity of the reaction are discussed.
The Beckmann rearrangement of cyclohexanone oxime (1) was carried out in the liquid phase in the ... more The Beckmann rearrangement of cyclohexanone oxime (1) was carried out in the liquid phase in the presence of a series of acid zeolites (HY-20, HY-50, HY-100, HYD, and HZSM-5) at different reaction temperatures. Together with e-caprolactam (2). 5-cyano-1-pentene (3), and cyclohexanone (4) were present in the reaction mixtures. From the selectivity curves of 2 and 3, it can be concluded that a Ritter equilibrium between 2 and 3 occurs under our experimental conditions, the direction of the process depending strongly on the hydrophobicity of the catalyst. The influence of the level of Na+ exchange and of the framework Si/AI ratio on the total conversion and the selectivity of 2 reveals that medium and strong acid sites (p& < 0) catalyze the reaction. Finally, no appreciable variations in the specific activity of the catalyst were observed when changing from a tridirectional large pore size sample (Y) to a medium pore size (ZSM-5).
Modified mordenites have been used in the direct conversion of glucose into 5-hydroxymethylfurfur... more Modified mordenites have been used in the direct conversion of glucose into 5-hydroxymethylfurfural (5-HMF) in two different media: the ionic liquid 1-butyl-3-methylimidazolium bromide ([BMIM]Br) and a biphasic system composed of water–acetone and ethyl acetate.
This paper reports the results obtained in the synthesis, characterization and catalytic activity... more This paper reports the results obtained in the synthesis, characterization and catalytic activity of thiol-MCM-41 materials synthesized using an improved method of preparation. This novel method of synthesis includes the partial replacement of the surfactant used previously-hexadecyltrimethylammonium bromide, for a shorter chain surfactant such as dodecyltrimethylammonium bromide. It also includes the use of tetramethylammonium hydroxide (TMAOH) as co-structuring agent instead of NaOH. The materials obtained from this modified gels present a higher order in the channels arrangement confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. These materials incorporates an important amount of thiol groups which can be oxidized with H 2 O 2 in order to obtain the corresponding sulfonic groups, with a very strong acidity. The catalysts so obtained have been tested in the esterification of glycerol with fatty acids-oleic and lauric. The results obtained indicate that the catalysts prepared with mixtures of surfactants are more selective to the monoglycerides than the ones synthesized only with hexadecyltrimethylammonium bromide, probably due to the higher order in the channels packing.
SAPO-34 silicoaluminophosphates are well known as catalysts for the synthesis of light olefins–et... more SAPO-34 silicoaluminophosphates are well known as catalysts for the synthesis of light olefins–ethylene and propylene–from methanol by using the methanol to olefins (MTO) process, first described by Mobil. SAPO-18, which has a microporous framework structure related to but crystallographically distinct from SAPO-34, has been much less studied but promises to be a potential catalyst in the MTO process. The main drawback of these catalysts in this reaction is their rapid deactivation, due to the deposition of heavy carbonaceous products–coke–on the surface of the solid avoiding the access of methanol molecules to the active centres located inside the pores of the SAPO catalysts. We have used different mesoporogen agents–nanoparticulate carbons and chitosan–aiming to generate mesoporosity in the SAPO-18 crystals, in an attempt to improve the accessibility of the reagent to the active centres of SAPO-18 and, in that way, inhibit catalyst deactivation. All the materials prepared in this work present similar framework composition and silicon distribution and the main difference among them is the hierarchical porosity generated by the mesoporogen additives use in the synthesis, as determined by STEM. Using chitosan polymer as a secondary template results in an increase of the external surface, which improved significantly the internal diffusivity enhancing the life time of the catalyst in the MTO process.
A series of high-acidity, tailored pore size, MCM-41 catalysts was prepared and tested for the es... more A series of high-acidity, tailored pore size, MCM-41 catalysts was prepared and tested for the esterification of glycerol with stearic acid making use of the spontaneous structure swelling occurring at high temperature hydrothermal synthesis. Optimal conditions for surfactant removal, propylthiol post-synthesis grafting and oxidation were found, leading to final sulphur loadings comparable to those of the materials synthesized by co-condensation. A relevant influence of the pore size on the catalytic performance was found, leading to an optimal size of the porous system which maximized the yield to the desired monostearine.
... Pore-size control of AI-MCM-41 materials by spontaneous swelling Isabel Diaz, Joaquin P6rez-P... more ... Pore-size control of AI-MCM-41 materials by spontaneous swelling Isabel Diaz, Joaquin P6rez-Pariente* and Enrique Sastre Instituto de Cat~disis y Petroleoquimica ... Pore diameter distribution was obtained using argon as adsorbate and following the Horvath-Kawazoe method. ...
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