Synthesis of TiO2–ZrO2 Mixed Oxides via the Alginate Route: Application in the Ru Catalytic Hydrogenation of Levulinic Acid to Gamma-Valerolactone

In this work, high surface area mono- and binary oxide materials based on zirconia and titania synthetized via the alginate route were applied as supports of ruthenium catalysts used in levulinic acid hydrogenation towards γ–valerolactone. The physicochemical properties of the catalysts were investigated using surface (like time-of-flight secondary ion mass spectrometry (ToF-SIMS), transmission electron microscopy (TEM)) and bulk techniques (temperature-programmed reduction (TPR), X-ray diffraction (XRD)). The obtained results exhibited that the proposed synthesis method allows for modification of the shape, morphology, and surface properties of the studied materials. These catalysts were tested in levulinic acid hydrogenation, in which catalytic support is known to be crucial. The results revealed that the titania-supported catalyst was the most active in the reaction mentioned above, while the highest mechanical stability was observed for zirconia-supported materials.

Dehydration of Alginic Acid Cryogel by TiCl4 vapor: Direct Access to Mesoporous TiO2 @C Nanocomposites and Their Performance in Lithium-Ion Batteries

A new strategy for the synthesis of mesoporous TiO₂ @C nanocomposites through the direct mineralization of seaweed-derived alginic acid cryogel by TiCl₄ through a solid/vapor reaction pathway is presented. In this synthesis, alginic acid cryogel can have multiple roles; i) mesoporous template, ii) carbon source, and iii) oxygen source for the TiO₂ precursor, TiCl₄ . The resulting TiO₂ @alginic acid composite was transformed either into pure mesoporous TiO₂ by calcination or into mesoporous TiO₂ @C nanocomposites by pyrolysis. By comparing with a nonporous TiO₂ @C composite, the importance of the mesopores on the performance of electrodes for lithium-ion batteries based on mesoporous TiO₂ @C composite was clearly evidenced. In addition, the carbon matrix in the mesoporous TiO₂ @C nanocomposite also showed electrochemical activity versus lithium ions, providing twice the capacity of pure mesoporous TiO₂ or alginic acid-derived mesoporous carbon (A600). Given the simplicity and environmental friendliness of the process, the mesoporous TiO₂ @C nanocomposite could satisfy the main prerequisites of green and sustainable chemistry while showing improved electrochemical performance as a negative electrode for lithium-ion batteries.

Synthesis and characterization of potential stereoisomeric and degradation impurities of ulipristal acetate

Potential stereoisomeric and degradation impurities of UPA has been synthesized through practical approaches which would be valuable for the quality control of UPA.