Delfina Serrano

Delfina Serrano
Spanish National Research Council | CSIC · Instituto de Lenguas y Culturas del Mediterráneo y Oriente Próximo

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66
Publications
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2,885
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Citations since 2016
0 Research Items
1352 Citations
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250

Publications

Publications (66)
Article
A number of catalysts made of Ni particles of different size distributions supported on a hierarchical beta zeolite (Ni/h-beta) were prepared and tested in the hydroreforming of low-density polyethylene (LDPE) thermal cracking oils. The materials were prepared by identical impregnation method but using different nickel precursors: chloride, nitrate...
Article
The effect of Ru on co-impregnated NiRu-supported hierarchical Beta zeolite (NiRu/h-Beta) and Ru/h-Beta as catalysts in the hydroreforming of the oil obtained by LDPE thermal cracking has been investigated, determining the thermal stability of the metal particles after two reaction-regeneration cycles. The formation of Ni–Ru particles on the fresh...
Article
Full-text available
To alleviate the chronic inflammation, nasal obstruction, and loss of sense of smell that produces the rhinosinusitis disease, ordered mesoporous materials and hierarchical zeolites could be used for slow and sustained corticoid (methylprednisolone hemisuccinate conjugate) release. The correlations between delivery performance of methylprednisolone...
Article
Fuel production from plastics is a promising way to reduce landfilling rates while obtaining valuable products. The usage of Ni-supported hierarchical Beta zeolite (h-Beta) for the hydroreforming of the oils coming from LDPE thermal cracking has proved to produce high selectivities to gasoline and diesel fuels (>80%). In the present work, the effec...
Article
The catalytic oxidative desulphurization (ODS) of S-containing aromatic compounds has been investigated over a hierarchical TS-1 zeolite prepared from silanized protozeolitic units, characterized by having, additionally to the zeolitic micropores, a secondary porosity within the supermicro/mesopore region. A standard TS-1 sample has been employed a...
Article
The deactivation and regeneration of Ni supported over hierarchical Beta zeolite catalyst was investigated. Ni/h-Beta was deactivated by coke deposition during the hydroreforming of the product from LDPE thermal cracking, being this coke mostly located inside the micropores (71% coverage). Its regeneration by calcination in stagnant air at 550 °C f...
Article
Hierarchical ZSM-5 zeolites were prepared by crystallization of silanized protozeolitic units employing silylated polypropylene oxide diamine polymers as organosilanes. The influence of the (Sipol/Sigel) molar ratio was investigated within 0–0.15 range. High synthesis yields (∼90%) of well-crystallized hierarchical zeolites exhibiting a high propor...
Article
The thermal cracking at 400 °C of pure polyolefins—low density polyethylene (LDPE), high density polyethylene (HDPE) and polypropylene (PP) and a standard polyolefin mixture (46 % LDPE + 27 % HDPE + 28 % PP)—was studied together with the catalytic hydroreforming of the obtained oils over Ni/h-beta at 310 °C under 20 bar of hydrogen. The oils obtain...
Article
The present review is aimed at exploring the field of the catalytic cracking of polyolefins over solid acids, focusing on the role played by the catalysts toward the synthesis of fuels and chemicals as well as on the reaction systems currently used. Initially, conventional solid acids, such as micrometer sized crystal zeolites and silica–alumina, w...
Article
The oil obtained from the thermal cracking of low-density polyethylene (LDPE) is formed mainly by linear hydrocarbons with a high quantity of olefins, which hinders the possible application of this product in the formulation of transportation fuels. However, hydroreforming of this oil using bifunctional catalysts with high accessibility to the acti...
Article
The effect of the calcination conditions on the properties and catalytic performance of hierarchical ZSM-5 zeolite has been investigated using different reactions as catalytic tests: acylation of aromatic substrates and rearrangement of linear and cyclic epoxides. The hierarchical h-ZSM-5 material was prepared by crystallization of silanized pro...
Article
The hydroreforming of the liquid product resulting from LDPE thermal cracking at 400°C (C5–C40) has been studied using Ni supported hierarchical zeolites (Ni/h-ZSM-5, Ni/h-Beta) and mesostructured materials (Ni/Al-MCM-41 and Ni/Al-SBA-15) as catalysts. Hydroreforming experiments were carried out at 310°C under 20bar of hydrogen. All the catalysts w...
Article
Hierarchical ZSM-5 zeolite has been synthesized by means of a method involving a precrystallization stage to form the protozeolitic units, the addition and subsequent grafting of both silanization and alkoxylation agents, and a final hydrothermal crystallization. The influence of the alkoxylation with different alcohols (methanol, ethanol, 2-propan...
Article
Full-text available
Two types of MFI zeolitic materials with improved accessibility, hierarchical zeolites and hybrid ordered mesoporous materials are here compared in terms of textural, acidic and catalytic properties. In both cases, protozeolitic units were employed as starting building blocks, the growth of which was perturbed by a silanization agent (hierarchic...
Article
The thermal cracking of HDPE in the presence of different amounts of phenol has been studied and compared with the reaction carried out without this solvent. HDPE conversion is enhanced with the amount of solvent, reaching a value of nearly 100% using a 1/10 HDPE/phenol ratio. The yield of the gaseous hydrocarbons also rose with the amount of pheno...
Article
Friedel-Crafts acylation is widely used for the production of aromatic ketones applied as intermediates in both fine chemicals and pharmaceutical industries. The reaction is carried out by using conventional homogenous catalysts, which represents significant technical and environmental problems. The present work reports the results obtained in the...
Article
The synthesis of hierarchical ZSM-5 from silanized protozeolitic units has been accomplished following a three step procedure comprising gel precrystallization at 90 °C, grafting of the seed silanization agent (SSA) and hydrothermal crystallization at 170 °C. The following four organosilanes were tested and investigated as SSAs: 3-aminopropyltrimet...
Article
Mesostructured SBA-15 materials, with both pure silica and aluminosilicate compositions, have been investigated as supports for the heterogenization of the chiral Mn(salen) catalyst using different methods: impregnation, direct ion exchange, indirect ion exchange, and coordinative anchoring on organosilica-functionalized supports. In the last case,...
Article
A higher 1-olefin (1-dodecene) was oxidized to 2-dodecanone and other ketones in a modified Wacker system featured by omitting the use of copper chloride and employing tert-butylhydroperoxide (TBHP) as oxidant. Acetonitrile was the solvent of choice due to its higher selectivity towards 2-dodecanone, the reaction occurring mostly in the interface....
Article
Abstract Microporous-mesoporous materials were synthesized by a two step process, based on the assembling of ZSM-5 precursors around CTAB micelles. The solids, named HZM, were characterized by XRD, FT-IR, TEM, N 2 adsorption-desorption isotherms, TG and NH 3 TPD analyses, exhibiting properties intermediate of those of A1-MCM-41 and ZSM-5 materi...
Article
A novel synthesis method has been applied to different zeolites (ZSM-5, ZSM-11 and Beta), based on the crystallization of silanized seeds, as a way to perturb the subsequent crystal growth step and to modify the zeolite textural properties. The zeolitic materials so obtained exhibit unique properties, such as the presence of ultra-small nanocrystal...
Article
Full-text available
En su libro Shari a and Custom in Libyan Tribal Society, Aharon Layish traduce al inglés 72 documentos árabes que contienen decisiones judiciales procedentes de los archivos de los tribunales de las ciudades libias de Ajdabiyya y Kufra durante un período comprendido entre principios de los años 30 y principios de los años 70 del siglo pasado. Los 7...
Article
In this work, catalytic cracking of low density polyethylene (LDPE) over nanocrystalline HZSM-5 zeolite in a batch reactor at 340°C was carried out with the aim of study both the catalyst resistance to deactivation and the catalyst regeneration process. For looking into the catalyst deactivation, consecutive polyethylene cracking experiments were c...
Article
The thermal cracking of a polyolefin (HDPE) has been investigated in the presence of solvents with different hydrogen-donating capabilities (9,10-dihydroanthracene, tetralin, decalin and 1-methylnaphthalene) with the aim of increasing the yields of C5–C32 α-olefins, which are valuable hydrocarbons for the chemical industry. The results have been al...
Article
The thermal cracking of HDPE in presence of different amounts of decalin was studied and compared with the reaction carried out in the absence of solvent. The decalin favours the mass and heat transfer during the reaction. In addition, it modifies the thermal degradation mechanism, which facilitates the formation of specific products. The use of de...
Article
A novel method has been developed for the synthesis of Ti-MCM-41 based on the preparation in a first step of an amorphous SiO2-TiO2 xerogel, followed by addition of a cationic surfactant and hydrothermal treatment. Ammonium hydroxide (NH3) and tetrapropylammonium hydroxide (TPAOH) solutions were used as basic agents during both the preparation of t...
Article
Catalytic cracking of both LDPE and HDPE has been studied using three different samples of nanocrystalline HZSM-5 zeolite as catalysts. The zeolite samples were synthesized under different conditions in order to obtain materials with different crystal sizes in the nanometer range (10–60nm) and high external surface areas (78–242m2/g). The plastic c...
Article
Pyrolysis coupled with gas chromatographic separation and mass spectrometry detection (Py–GC/MS) has been used to study the catalytic degradation of low-density polyethylene (LDPE). This novel approach allowed rapid screening of the catalytic activity of different acid solids and permitted a straightforward analysis of the resulting products. The r...
Article
Catalytic cracking of both LDPE and HDPE has been studied using three different samples of nanocrystalline HZSM-5 zeolite as catalysts. The zeolite samples were synthesized under different conditions in order to obtain materials with different crystal sizes in the nanometer range (10–60 nm) and high external surface areas (78–242 m 2 /g). The plast...
Article
ZSM-5 formed by aggregates of nanocrystals with ultra-small crystal size (10–20 nm) has been prepared by hydrothermal crystallization of clear synthesis mixtures at low temperatures (70–90 °C) under atmospheric pressure. Compared with the conventional autoclave treatment, this method leads to a significant reduction in the crystal size, although wi...
Article
Both thermal and catalytic cracking of mixtures consisting of low-density polyethylene (LDPE) and a lubricating oil base have been investigated in a continuous screw kiln reactor, provided with two reaction zones operating at different temperatures (T1/T2). The incorporation of the lubricating oil into the plastic leads to a significant decrease in...
Article
The behaviour of mesoporous silica as a support for anchored catalytic species depends on its physical and chemical surface properties, particularly those related with the hydroxyl groups. In this report, the number and nature of hydroxyl groups of a commercial silica sample calcined at different temperatures have been determined by titration with...
Article
Nanocrystalline HZSM-5 (crystal size around 25 - 60 nm) shows remarkable activity in the catalytic cracking of LDPE, HDPE and PP despite the low temperatures (340 - 380 °C) and catalyst loadings used (plastic / catalyst mass ratio = 100). Gaseous hydrocarbons are the main products with a maximum centered at C4, which are formed through a carbocatio...
Article
Both thermal and catalytic cracking of low-density polyethylene (LDPE) have been investigated using a screw kiln reactor. Thermal degradation gives rise to a broad product distribution whereas catalytic cracking over Al-MCM-41 leads mainly to hydrocarbons within the gasoline range (C5 ¿ C12) with selectivities up to 80%. The increase of the screw s...
Article
This chapter discusses the preparation and characterization of mesoporous silica spheres. The effect of different variables in the preparation of mesoporous silica spheres has been investigated through a two-phase method that requires tetrabutoxy silane as silica source, cetyltrimethylammonium chloride as surfactant, and water as solvent. The mater...
Article
This chapter presents the catalytic properties of micelle templated microporous and mesoporous materials for the conversion of low-density polyethylene. Both microporous and mesoporous micelle-templated aluminosilicates exhibit high catalytic activity for the low-density polyethylene (LDPE) cracking. Aluminium (Al)-SBA-15 materials are used for the...
Article
Thermal and catalytic cracking of both high and low-density polyethylene (HDPE and LDPE, respectively) under mild conditions have been investigated in order to study the properties of the solid waxy product so obtained. The catalysts employed were n-HZSM-5 and HY zeolites, amorphous silica–alumina, activated carbon, Pd charcoal powder and mesoporou...
Article
Thermal and catalytic degradation of low-density polyethylene (LDPE) has been investigated using a screw kiln reactor provided with two zones of reaction temperature. Thermal degradation experiments carried out at different temperatures and screw speeds have shown that this continuous system is suitable for the LDPE degradation, product outputs up...
Article
The initial steps of the thermal and catalytic cracking of low-density polyethylene (LDPE) at different temperatures and reaction times have been studied in batch operation. The catalysts employed were silica-alumina, USY zeolite and MCM-41. The thermal degradation follows a random scission mechanism with little contribution of isomerization and...
Article
The catalytic degradation of polypropylene and both low- and high-density polyethylene over different samples of zeolite beta has been investigated. Zeolite beta synthesized by the fluoride method has a low activity for the cracking of polyolefins, which is related to its large crystal size (12 μm) and poor aluminium incorporation. In contrast, zeo...
Article
HMCM-41, amorphous SiO2–Al2O3 and HZSM-5 zeolite have been studied as catalysts in the degradation of polystyrene (PS) at 375°C. HMCM-41 is the only catalyst that shows a slight increase in activity with regard to the thermal cracking, whereas the other two materials present similar or even lower conversions. This fact has been explained by the exi...
Article
A two-step sol–gel method has been developed for the synthesis of Al-containing micelle-templated silica (Al-MTS) with Si/Al atomic ratios in the range 8–45. The synthesis proceeds at ambient temperature, atmospheric pressure, acid medium and for only 3h. For the calcined materials, a decrease of both the d100 spacing and the pore size, as well as...
Article
The synthesis of VS-1 zeolites from SiO2-V2O5 xerogels has been carried out by wetness impregnation with TPAOH solutions, followed by autoclave crystallization. A method for the preparation of the starting xerogels has been developed which allows the V atoms to be incorporated in isolated positions of the amorphous silica solid. Although a part of...
Article
The synthesis of VS-1 zeolites from SiO2-V2O5 xerogels has been carried out by wetness impregnation with TPAOH solutions, followed by autoclave crystallization. A method for the preparation of the starting xerogels has been developed which allows the V atoms to be incorporated in isolated positions of the amorphous silica solid. Although a part of...
Article
The potential application of Al-containing MCM-41 for the catalytic degradation of polyolefinic plastics and used lubricating oils has been investigated and compared with the behavior of ZSM-5 zeolite and commercial amorphous SiO2-Al2O3. For all the studied raw plastics, MCM-41 presents significant higher activity than the amorphous catalyst, and e...
Article
The coincorporation of Ti and Al into the MFI zeolite framework has been investigated using a method based on the wetness impregnation of amorphous Al2O3–TiO2–SiO2 solids with TPAOH solutions and subsequent crystallization under autogenous pressure. The influence of the precursor addition sequence and the conditions during the amorphous cogel forma...
Article
The catalytic degradation of both low- and high-density polyethylene (LDPE and HDPE) and polypropylene (PP) has been investigated using MCM-41, a mesoporous aluminosilicate recently discovered, as catalyst. The results obtained have been compared to those of ZSM-5 zeolite and amorphous silica−alumina. For all the studied plastics, MCM-41 has been f...
Article
TS-2 has been synthesized from SiO2-TiO2 xerogels by wetness impregnation with TBAOH solutions and subsequent autoclaving at 170°C. The preparation of the raw materials through sol-gel methods leads to a stabilization of the Ti atoms by dispersion in isolated positions of the amorphous SiO2 network, which prevents the formation of undesired TiO2 ph...
Article
The crystallization mechanism of TS-1 has been investigated when this Ti-containing material is obtained from amorphous SiO2TiO2 solids impregnated with TPAOH solutions followed by thermal treatment under autogenous pressure. Samples with different degrees of crystallinity have been prepared and characterized by elemental analysis, X-ray diffracti...
Article
The synthesis of TS-1 and TS-2 zeolites from SiO2–TiO2 xerogels wetness impregnated with solutions of the structure-directing agent proceeds mainly through solid–solid transformations which allow the raw amorphous network to be reordered into crystalline frameworks.
Article
A new route for the synthesis of methyl tert-butyl ether (MTBE) from isobutane using a single catalytic system is developed in the liquid phase; the key of the process relies on the use of a bifunctional material, Al-TS-1, capable of catalysing the oxidation of isobutane with H2O2 and consequently etherification with methanol.
Article
Tetrahedral Al-containing MCM-41, prepared under ambient conditions, exhibits suitable catalytic properties for the conversion of low-density polyethylene into hydrocarbon feedstocks.
Article
Ti-containing ZSM-5 (Al-TS-1) has been synthesized by wetness impregnation of amorphous Al2O3-TiO2-SiO2 solids with TPAOH solutions and subsequent crystallization under autogenous pressure at 170°C. The cogel containing aluminum, titanium and silicon oxides used as raw material has been prepared following a two-step (acid-base) sol-gel process whic...
Article
Sol-gel methods have been applied for the preparation of amorphous SiO2-TiO2 solids having Si-O-Ti bonds, in order to get a suitable raw material to synthesize TS-1. The procedure involves the wetness impregnation of these solids with TPAOH solutions followed by crystallization under autogeneous pressure. This method seems to be also successful in...
Article
TS-1 has been synthesized following a method based on the wetness impregnation with a template solution of amorphous SiO2TiO2 solids followed by crystallization under autogenous pressure. The preparation of the raw SiO2TiO2 solids has been carried out by different two-step sol-gel processes in order to achieve the formation of SiOTi bonds prior...
Article
Full-text available
A principios de Septiembre de 1125 Alfonso el Batallador partió de Zaragoza en una expedición contra al-Andalus cuyo principal objetivo parece ser que era atacar Granada’. Según las crónicas, los cristianos de Granada se pusieron en contacto con Alfonso, incitándole a tomar aquella plaza y tentando al monarca con las riquezas que en ella había, ade...

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