Artículos SCI
2024
2024
Química de Superficies y Catálisis
Mechanistic insights into methanol carbonylation to methyl acetate over an efficient organic template-free Cu-exchanged mordenite
Luque-Alvarez, LA; Gonzalez-Arias, J; Romero-Sarria, F; Reina, TR; Bobadilla, LF; Odriozola, JACatalysis Science & Technology, 14 (2024) 128-136
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Currently, acetic acid is produced via the carbonylation reaction of methanol with the main route entailing the use of homogeneous noble metal-based catalysts, which has certain limitations, including the use of polluting alkyl halide promoters and difficulty in catalyst recovery. To overcome these challenges, the exploration of alternative methods utilizing heterogeneous catalysts, particularly zeolites with copper as a redox center, has gained attention. Nonetheless, the conversion and selectivity obtained are sought after to compete against the homogeneous route. Therefore, a deeper understanding of the reaction and mechanism is needed to determine the weak points and overcome them. In this study, we propose the use of time-resolved operando DRIFTS-MS to study the methanol carbonylation reaction over a Cu–H-MOR catalyst. The study aimed to propose a reaction mechanism through an investigation of the behavior of the catalyst, including potential identification of the location of the copper redox center in the zeolite. The catalytic performance of the Cu–H-MOR catalyst was also evaluated, demonstrating its activity and stability in the methanol carbonylation reaction. The operando DRIFTS-MS results provide insights into the reaction mechanism and the involvement of the acid and redox centers in the process. Based on the findings, we propose a reaction mechanism for methanol carbonylation on Cu–H-MOR zeolite: (i) methanol dehydration, (ii) CO insertion into methoxide groups, (iii) reaction between dimethyl ether and acetyl groups, and (iv) hydrolysis of methyl acetate. Overall, we believe that this work contributes to a deeper understanding of the heterogeneous route for acetic acid production and offers potential avenues for optimizing the process.
Enero, 2024 | DOI: 10.1039/d3cy01271a
Fotocatálisis Heterogénea: Aplicaciones - Reactividad de Sólidos
Investigating the room- and cryo-milling impact in lignocellulosic biomass and its consequence over pyrolysis and oxidative treatments
Pérez, CR; González, MDA; Sarria, FR; López, MDH; Gallego, JMCJournal of Cleaner Production, 437 (2024) 140761
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The lignocellulosic biomass recalcitrance is the uppermost factor for the utilization of this renewable resource. The development of new pre -treatments, addressed to enhance performance in lignocellulosic biomass conversion into biofuels, fine chemicals, and as potential sources of building blocks for materials, must be focus in two main areas: effectiveness (cost-effective and chemical effective) and green chemistry. In this research, a set of different biomass sources (farmer, harvested wild trees and secondary products) were studied to evaluate the high efficiency of the non -liquid nitrogen (LN) and LN-treated biomass samples' planetary ball milling performance. The samples have been characterized by particle size distribution, thermogravimetric, FT-IR, statistical chemometric and chemical oxidation analysis. The results have shown a high level on the rupture of the crystallinity and depolymerization degrees of the cellulose and the lignin, for both, non-LN and LN-treated samples. The thermogravimetric analysis showed a clear diminishing in temperature degradation, and a larger amount of biomass degraded at lower temperature, as well as, a high chemical oxidation degree than not milled samples. Finally, the LN-treated samples even exhibited a lower degradation temperature, a larger amount of biomass degraded at lower temperature and a higher oxidation degree, than those non-LN milled.
Enero, 2024 | DOI: 10.1016/j.jclepro.2024.140761
2023
2023
Química de Superficies y Catálisis
Alkane metathesis over immobilized pincer-ligated iridium complexes: Effect of support nature
Megías-Sayago, C; Centeno-Vega, I; Bobadilla, LF; Ivanova, S; Rendon, N; Suarez, AApplied Catalysis B-Environmental, 338 (2023) 123002
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![](https://icms.us-csic.es/sites/icms.us-csic.es/files/1-s2_418.png)
In this work, catalytic alkane metathesis has been evaluated as a suitable approach to upcycle hydrocarbons (polyolefins) at moderate temperatures. To this end, a pincer-ligated iridium complex (dehydrogenation catalyst) has been combined with a rhenium-based (metathesis) catalyst, being the effect of immobilizing the Ir complex over different supports deeply investigated. FTIR spectroscopy has been used to confirm the complex grafting and to elucidate the anchoring site to the support. Additionally, the supports have been dehydroxylated at different conditions to evaluate its possible impact in both the complex grafting and the catalytic activity. The influence of the support nature and its participation in the catalytic reaction have been clearly evidenced.
Diciembre, 2023 | DOI: 10.1016/j.apcatb.2023.123002 | Digital CSIC: http://hdl.handle.net/10261/353935
Materiales de Diseño para la Energía y Medioambiente
Incorporation of bioactive compounds from avocado by-products to ethyl cellulose-reinforced paper for food packaging applications
Acquavia, MA; Benitez, JEJ; Bianco, G; Crescenzi, MA; Hierrezuelo, J; Grife-Ruiz, M; Romero, D; Guzman-Puyol, S; Heredia-Guerrero, JAFood Chemistry, 429 (2023) 136906
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![](https://icms.us-csic.es/sites/icms.us-csic.es/files/1-s2_391.png)
Reinforced films were fabricated by impregnating paper in ethyl cellulose solutions. After solvent evaporation, the infused ethyl cellulose acted as binder of the paper microfibres and occupied the pores and cavities, thus improving the mechanical and barrier properties. To prepare active films, avocado by-products from guacamole industrial production were extracted in ethyl acetate. Then, the extract (optimized to be rich in phenolic compounds and flavonoids and mainly composed by lipids) was incorporated to the paper reinforced with the highest content of ethyl cellulose. In general, the addition of the avocado by-products extract decreased the water uptake and permeability, improved the wettability, and increased the biodegradability in seawater and the antioxidant capacity. In addition, these films acted as barriers and retainers for Escherichia coli and Bacillus cereus. The potentiality of these materials for food packaging was demonstrated by low overall migrations and a similar food preservation to common low-density polyethylene.
Diciembre, 2023 | DOI: 10.1016/j.foodchem.2023.136906
Materiales y Procesos Catalíticos de Interés Ambiental y Energético
Photoreforming of glycerol to produce hydrogen from natural water in a compound parabolic collector solar photoreactor
Villachica-Llamosas, JG; Sowik, J; Ruiz-Aguirre, A; Colón, G; Peral, J; Malato, SJournal of Environmental Chemical Engineering, 11 (2023) 111216
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![](https://icms.us-csic.es/sites/icms.us-csic.es/files/1-s2_404.png)
To improve TiO2 for H2 generation, one strategy for the separation of photogenerated charges is the formation of heterostructures with other materials. In particular, NiO is a photocatalyst known for its good stability and low cost. However, no studies at pilot scale using solar energy have been described. Consequently, an evaluation of a physical NiO:TiO2 mixture at pilot scale (25 L) with natural irradiation (2.10 m2 of sun-exposed surface) and with simultaneous glycerol photoreforming was explored. NiO:TiO2 50 mg & sdot;L- 1 resulted in the highest hydrogen production, showing an STH = 1.44%, considering only the UV fraction of the solar irradiation. H2 and CO2 production were analysed by on-line GC; Glycerol, dissolved organic carbon, carboxylic acids and nickel leaching were also evaluated. The NiO:TiO2 mixtures rendered a systematically lower H2 production in natural water than in high-purity water. The increase of ionic strength increased the mean size of particle clusters, promoting rapid sedimentation. All this indicates the importance of testing under real field conditions for attaining reliable solar to hydrogen (STH) efficiency.
Diciembre, 2023 | DOI: 10.1016/j.jece.2023.111216
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