References of "Mendoza Gallego, Carlos"
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See detailTransitioning from conventional batch to microfluidic processes for the efficient singlet oxygen photooxygenation of methionine
Mendoza Gallego, Carlos ULiege; Emmanuel, Noémie ULiege; Pàez Martinez, Carlos ULiege et al

in Journal of Photochemistry and Photobiology A : Chemistry (in press)

Singlet oxygen-based photocatalytic oxygenation reactions have emerged as an efficient technology to synthesize value-added organic molecules. Among organic substrates, bio-sourced molecules such as ... [more ▼]

Singlet oxygen-based photocatalytic oxygenation reactions have emerged as an efficient technology to synthesize value-added organic molecules. Among organic substrates, bio-sourced molecules such as aminoacids or terpenes have a promising forecast as synthetic building blocks. A pseudo first-order kinetic study for the photocatalytic oxygenation of natural amino acid (L)-methionine was carried out in a macroscopic batch reactor. Various parameters were studied, including the effect of the photosensitizer (Rose Bengal, RB) concentration, the intensity of the light and the O2 flow in terms of apparent kinetic constants and space-time yields. The identification of important limiting parameters as pressure, gas flow or light efficiency during the photocatalytic oxygenation of methionine allowed its transition from macroscopic batch reactor to continuous-flow microreactor. [less ▲]

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See detailProtective nature of nano-TiN coatings shaped by EPD on Ti substrates
Mendoza Gallego, Carlos ULiege; Gonzalez, Zoilo; Gordo, Elena et al

in Journal of the European Ceramic Society (2017)

The hardness and corrosion resistance of TiN coatings, processed by Electrophoretic Deposition (EPD) to cover polished and unpolished Ti substrates, have been evaluated. A deposition time of 5 min has ... [more ▼]

The hardness and corrosion resistance of TiN coatings, processed by Electrophoretic Deposition (EPD) to cover polished and unpolished Ti substrates, have been evaluated. A deposition time of 5 min has been enough to obtain a cohesive layer of 7–8 μm in thickness. The coatings were thermally treated in vacuum atmosphere at 1200 °C for 1 h with heating and cooling rates of 5 °C min−1. The surfaces have been covered homogeneously optimizing the properties of the Ti substrates. Uniform and dense TiN coatings have been obtained onto polished substrates, while on unpolished Ti the nitrogen diffuses toward the substrate, moderately dissolving TiN coating. The nanohardness values of the polished samples have been increased from 2.8–4.8 GPa up to 6.5–8.5 GPa. Besides, the corrosion current density has been reduced more than one order of magnitude obtaining a protective efficiency of 82%. These values have been compared with other works in literature where authors used complex and costly processing techniques, demonstrating the strong impact of the colloidal processing over the specific properties of the material. [less ▲]

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See detailSurface Modification of Powder Metallurgy Titanium by Colloidal Techniques and Diffusion Processes for Biomedical Applications
Ureña, Julia; Mendoza Gallego, Carlos ULiege; Ferrari, Begoña et al

in Advanced Engineering Materials (2017), 19(6),

This contribution focuses on modifying the composition and surface characteristics of powder metallurgy titanium substrates to improve their wear resistance and to reduce the surface Younǵs modulus, while ... [more ▼]

This contribution focuses on modifying the composition and surface characteristics of powder metallurgy titanium substrates to improve their wear resistance and to reduce the surface Younǵs modulus, while maintaining the corrosion resistance and biocompatibility. The modification consists of Mo and TiN coatings produced by colloidal techniques which are deposited by electrophoretic deposition (EPD) or spraying onto green or sintered titanium substrates. The final surface structures are formed during a heat treatment, during which diffusion and consolidation of the layers take place. The surfaces are characterised by XRD, SEM, and micro-indentation; showing diffusion areas of between 40 and 85 microns with clear microstructural changes as well as higher hardness values. [less ▲]

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See detailScalable Photocatalytic Oxidation of Methionine under Continuous-Flow Conditions
Emmanuel, Noémie ULiege; Mendoza Gallego, Carlos ULiege; Winter, Marc et al

in Organic Research Process & Development (2017)

Highly efficient and chemoselective singlet oxygen oxidation of unprotected methionine was performed in water using a continuous mesofluidic reactor. Sustainable process engineering and conditions were ... [more ▼]

Highly efficient and chemoselective singlet oxygen oxidation of unprotected methionine was performed in water using a continuous mesofluidic reactor. Sustainable process engineering and conditions were combined to maximize process efficiency and atom-economy, with virtually no waste generation and safe operating conditions. Three water soluble metal-free photosensitizers (Rose Bengal, Methylene Blue, and tetrakis(4-carboxyphenyl)porphyrin) were assessed. The best results were obtained with Rose Bengal (0.1 mol%) at room temperature under white light irradiation and a slight excess of oxygen. Process and reaction parameters were monitored in real-time with in-line NMR. Other classical organic substrates (alpha-terpinene and citronellol) were oxidized under similar conditions with excellent performances. [less ▲]

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See detailIntegrated continuous flow photoreactors: Photooxidation of (L)-methionine with singlet oxygen
Emmanuel, Noémie ULiege; Mendoza Gallego, Carlos ULiege; Lismont, Marjorie ULiege et al

Poster (2016, December 08)

Development of photochemistry in macroscopic batch reaction vessels is hampered due to inherent limitations: light penetration remains superficial, resulting in inhomogeneous irradiation and hence to side ... [more ▼]

Development of photochemistry in macroscopic batch reaction vessels is hampered due to inherent limitations: light penetration remains superficial, resulting in inhomogeneous irradiation and hence to side-reactions or product degradation due to overexposure. The recent implementation of photochemical processes in microreactors under continuous-flow conditions appeared to be much more powerful than its batch analogue in terms of irradiation efficiency and light penetration. Furthermore, the fine control of residence time ensures an accurate control of the irradiation time, avoiding side-reactions and degradation. The photooxidation of (L)-methionine with singlet oxygen using Rose Bengal as a sensitizer was successfully implemented in a microreactor setup and led to total and selective conversion into methionine sulfoxide, an important building block for the organic synthesis of peptides or functionalized amino acid. The reaction was performed in 2 min while the same reaction in batch took 2h. [less ▲]

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See detailIntegrated continuous flow photoreactors: Photooxidation of (L)-methionine with singlet oxygen
Emmanuel, Noémie ULiege; Mendoza Gallego, Carlos ULiege; Lismont, Marjorie ULiege et al

Poster (2016, October 13)

Development of photochemistry in macroscopic batch reaction vessels is hampered due to inherent limitations: light penetration remains superficial, resulting in inhomogeneous irradiation and hence to side ... [more ▼]

Development of photochemistry in macroscopic batch reaction vessels is hampered due to inherent limitations: light penetration remains superficial, resulting in inhomogeneous irradiation and hence to side-reactions or product degradation due to overexposure. The recent implementation of photochemical processes in microreactors under continuous-flow conditions appeared to be much more powerful than its batch analogue in terms of irradiation efficiency and light penetration. Furthermore, the fine control of residence time ensures an accurate control of the irradiation time, avoiding side-reactions and degradation. The photooxidation of (L)-methionine with singlet oxygen using Rose Bengal as a sensitizer was successfully implemented in a microreactor setup and led to total and selective conversion into methionine sulfoxide, an important building block for the organic synthesis of peptides or functionalized amino acid. The reaction was performed in 20 min while the same reaction in batch took 2h. [less ▲]

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See detailImprovement of TiN nanoparticles EPD inducing steric stabilization in non-aqueous suspensions
Mendoza Gallego, Carlos ULiege; González, Zoilo; Castro, Yolanda et al

in Journal of the European Ceramic Society (2016), 36(2), 307-317

In this work, the process parameters involved in the electrophoretic deposition (EPD) to obtain thin TiN films was studied and optimised. The stability of commercial TiN nanopowder in isopropyl alcohol ... [more ▼]

In this work, the process parameters involved in the electrophoretic deposition (EPD) to obtain thin TiN films was studied and optimised. The stability of commercial TiN nanopowder in isopropyl alcohol adding a cationic polymer (polyethylenimine) as dispersant, with different molecular weights, was investigated to determine the kinetics of the deposition and to reach the most efficient EPD process. Cathodic EPD was performed over electro-polished stainless steel substrates. It was found that the provided dispersion when the PEI with the highest molecular weight was added to the suspension, leads to the best deposition behaviour for short times. New flocculation phenomena were described which affect to the sticking factor, and thus to the evolution of the EPD kinetics. As a result of the designed stabilization system, a reliable and versatile EPD method to produce well consolidated nano-TiN coatings at 1200 °C in vacuum atmosphere was described. [less ▲]

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See detailCharacterization of photoactive coatings of SiO2 nanoparticles and Rose Bengal onto glass surfaces
Mendoza Gallego, Carlos ULiege; Lismont, Marjorie ULiege; Pàez Martinez, Carlos ULiege et al

Conference (2016)

The fluorescence emission and singlet oxygen (1O2) production have been widely investigated over the last decade due to high-value added applications such as organic chemical synthesis1, wastewater ... [more ▼]

The fluorescence emission and singlet oxygen (1O2) production have been widely investigated over the last decade due to high-value added applications such as organic chemical synthesis1, wastewater treatment2 or photodynamic cancer therapy3. This work is dedicated to the synthesis and deposition of SiO2 nanoparticles on glass surfaces using Stober’s process and dip coating, respectively. The adherence was improved through the incorporation of different concentrations of these nanoparticles into a TiO2 matrix. Additionally, the speed of dip coating was used to modify SiO2 thicknesses. Rose bengal was covalently anchored to SiO2 coatings through (3-aminopropyl)triethoxysilane (APTES) linker. UV, IR, fluorescence, SEM and profilometry were used to characterize the corresponding films and the efficiency for singlet oxygen production was measured by oxidation of the amino acid methionine. The immobilization of SiO2 nanoparticles photosensitized with rose bengal showed promising results for the production of singlet oxygen. [less ▲]

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See detailTiO2 and TiO2-SiO2 coated cement: Comparison of mechanic and photocatalytic properties
Mendoza Gallego, Carlos ULiege; Valle, Alberto; Castellote, Marta et al

in Applied Catalysis B : Environmental (2015), 178

An increasingly known application of nanomaterials in the construction industry is related to the photoactivity ability of semiconductors, where nano-anatase TiO2 is perhaps the most well-known ... [more ▼]

An increasingly known application of nanomaterials in the construction industry is related to the photoactivity ability of semiconductors, where nano-anatase TiO2 is perhaps the most well-known photocatalytic semiconductor and one which possesses a strong oxidizing capability. To analyze the photo-efficiency of four TiO2 coatings and the effect of SiO2 interlayer on the mechanic and photocatalytic activity in Rhodamine B (RhB) and NOx photodegradation, two photocatalytic cement series have been prepared. First, cement mortar was coated with three commercial TiO2 suspensions (GG1, GC7 and CG13) and a home-made titania sol-gel (TEA), and secondly an insertion of a SiO2 layer was applied on cement surface before spraying the TiO2 layer.All studied TiO2-cements exhibited a significant RhB and NOx photodegradation, arising almost total RhB molar conversions, and upper 53% for NOx photo-oxidation respectively. Nevertheless, although SiO2 layer deposited in between mortar and TiO2-cement did not stabilize the commercial TiO2 coatings, a good adhesion was observed when silica was applied joint to the home-made titania gel (TEA), probably as a consequence of the interactions encountered between SiO2 and TiO2 gels. CG7-Si-Cem exhibited high rate at shorter irradiation times, but TEA-Cem and TEA-Si-Cem can be considered as very interesting and potential photocatalytic mortars due to useful mechanical properties, with a very good coatings adhesion that provides promising outdoor use, and good photo-efficiencies in RhB and NOx photo-oxidation. [less ▲]

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See detailDispersion and stabilization of TiN and TiC nanoparticles in organic suspensions
Mendoza Gallego, Carlos ULiege; González, Zoilo; Castro, Yolanda et al

in Key Engineering Materials (2015), 654

In this work the stability of TiN and TiC nanopowders in isopropyl alcohol as well as the fabrication of dense and well adhered thin coatings based on TiN and TiC by electrophoretic deposition (EPD) have ... [more ▼]

In this work the stability of TiN and TiC nanopowders in isopropyl alcohol as well as the fabrication of dense and well adhered thin coatings based on TiN and TiC by electrophoretic deposition (EPD) have been evaluated in terms of zeta potential and mass deposited when hydrazine is added. The surface of TiN and TiC nanoparticles has been modified to improve the dispersion in isopropyl alcohol adding a cationic polymer (polyethylenimine) as dispersant with two different molecular weights. The influence of acidic/basic character of the solvent also has been evaluated in order to reach the most efficient EPD process. It was found that the adsorption of polyethylenimine with higher molecular weight can preserve the homogeneity of TiC coatings. The surface of TiN nanoparticles can be tuned in order to achieve a similar polyethylenimine adsorption which also improves the deposition in basic media. [less ▲]

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