Beatriz García

δ‐Valerolactone (DVL) is a monomer with promising applications in the production of biodegradable and biocompatible polymers. This study addresses, for the first time, a sustainable route for DVL production by coupling liquid‐phase furfural (FF) hydrogenation with 1,5‐pentanediol (1,5‐PDO) dehydrogenation, where FF acts as a hydrogen acceptor. In addition, the potential regeneration of 1,5‐PDO from FF, thereby contributing to the closure of the material cycle, is evaluated. For this purpose, Cu─Ni─Al hydrotalcites‐derived catalysts with varying Cu:Ni ratios were prepared. Comprehensive physicochemical characterization revealed that Cu:Ni ratio strongly influences the catalyst structure and the textural properties, significantly affecting the catalytic performance of the catalysts. Catalytic tests allowed for obtaining substrate conversion values above 90% and DVL yields over 65%, demonstrating that hydrogen‐transfer coupling significantly promotes DVL production under liquid‐phase conditions. Kinetic studies based on a simplified model provided preliminary estimates of the apparent activation energies of 120 kJ mol ⁻¹ for FF hydrogenation and 80 kJ mol ⁻¹ for 1,5‐PDO dehydrogenation, highlighting the potential of dual catalytic systems for biomass valorization and the production of sustainable monomers under liquid‐phase conditions.

Sorbitol production from glucose was studied through catalytic transfer hydrogenation (CTH) over Raney nickel catalysts in alcohol media, used as solvents and hydrogen donors. It was found that alcohol sugars, sorbitol and mannitol, can be derived from two hydrogen transfer pathways, one produced involving the sacrificing alcohol as a hydrogen donor, and a second one involving glucose disproportionation. Comparison between short-chain alcohols evidenced that ethanol was able to reduce glucose in the presence of Raney nickel under neutral conditions. Side reactions include fructose and mannose production via glucose isomerization, which occur even in the absence of the catalyst. Blank reaction tests allowed evaluating the extension of the isomerization pathway. The influence of several operation parameters, like the temperature or the catalyst loading, as well as the use of metal promoters (Mo and Fe-Cr) over Raney nickel, was examined. This strategy opens new possibilities for the sustainable production of sugar alcohols.

A family of catechol-based submicron particles, with sizes between 200 and 300 nm, was tested for the removal of Cd(II), Pb(II) and Cr(VI) in water. The highest adsorption capacity was obtained with catechol-based particles in the case of Pb(II), followed by Cd(II). However, the catechol particles failed to adsorb Cr(VI). Our results indicate an up to four-fold increase of the adsorption capacity of these particles compared to that of activated carbon under the same experimental conditions. To check the biocompatible character of the submicron particles, their stability was evaluated in a phosphate buffer solution (PBS) and in a cell culture medium. The results confirmed that the presence of proteins in the medium favors their stability. A bioluminescent Vibrio fischeri test and a cytotoxicity assay on the HepG2 cell line were used to determine that the catechol particles did not exhibit any substantial toxicity. The results show that these catechol-based particles can be used as an efficient biocompatible adsorbent to remove heavy metals at extremely low concentrations.