MEGÍAS SAYAGO , Cristina

El concepto de biorrefinería, aunque conocido desde finales del siglo pasado , ha sido objeto de numerosas definiciones durante la última década . Según la Agencia Internacional de Energía (Bioenergía, apartado 42), biorrefinería hace referencia al procesado sostenible de biomasa con el fin de obtener un amplio abanico de bioproductos...

One of the most trending topics in catalysis recently is the use of renewable sources and/or non-waste technologies to generate products with high added value. That is why, the present review resumes the advances in catalyst design for biomass chemical valorization. The variety of involved reactions and functionality of obtained molecules...

Gold is without a doubt the best known metal for chemical oxidation. The noblest of the noble metals gained its place because of its resistance to overoxidation, low temperature of operation, especially in gas-phase oxidation, and fairly good selectivity when required. The aim for sustainable development and the need for new technologies open...

The present work showcases the versatility of nanogold systems supported on Zn-doped ceria when applied in two important environmental processes, the total CO oxidation, and the liquid phase oxidation of glucose to gluconic acid. In the CO oxidation the suitability of these materials is clearly demonstrated achieving full conversions even at...

The influence of the crystal structure and chemical nature of some ionic liquid/phosphomolybdate hybrids on their catalytic activity in the epimerization of glucose is studied. A clear evidence for structure-activity relationship is found. The inorganic part of the hybrid assures the active sites for the reaction; meanwhile the organic cation...

The catalytic activity of a simple Au/Al2O3 catalytic system prepared by the direct anionic exchange (DAE) method was evaluated in the selective 5-hydroxymethylfurfural (HMF) oxidation under mild conditions, using molecular oxygen as the oxidant. The influence of the HMF/NaOH ratio and reaction time on product yield and distribution were...

Base-free aerobic oxidation of glucose in presence of Au/Al2O3, Au/CeO2, Au/CeO2(20 wt%)/Al2O3, Au/CeO2(25 wt%)/ZrO2 and Au/CeO2(50 wt%)/ZrO2 catalysts using molecular oxygen at atmospheric pressure is studied. Within the whole series high conversion and selectivity to gluconic acid are observed after 18 h of reaction at 120 °C. The activity...

The influence of the protecting agent's nature on gold particle size and dispersion was studied in this work over a series of gold-based catalysts. CO and glucose oxidation were chosen as catalytic reactions to determine the catalyst's structure–activity relationship. The nature of the support appeared to be the predominant factor for the...

A series of gold catalysts supported on pure CeO2, ZrO2, and two different Ce-Zr mixed oxides have been prepared and tested in the 5-hydroxymethyl-2-furfural oxidation reaction. All catalysts show high catalytic activity (100% conversion) and important selectivity (27–41%) to the desired product i.e., 2,5-furandicarboxylic acid at low...

The problems associated with the use of molecular hydrogen (transportation, storage and high cost) have pushed scientists to the pursuit of efficient hydrogen donors, able to reduce chemical bonds in the presence of catalysts through catalytic transfer hydrogenation (CTH) reactions. In this sense, formic acid stands up as one of the most...

A new approach for understanding PrOx reaction over gold catalysts is proposed in this work. The competition between H2 and CO oxidation has been studied over a series of Au/MOx/Al2O3 (M = Ce and Co) catalysts in simulated post-reforming gas stream, containing H2O and CO2 for H2 cleanup goals. The catalysts' behavior is correlated to their...

This work is devoted to the study of viability of immobilized gold colloids on carbon as catalysts for the base-free glucose oxidation reaction with a special emphasis made on catalysts' recycling, operational life and possible routes for deactivation/reactivation under batch conditions. The observed catalytic behavior is related to all...

A series of gold nanoparticles in the 4–40 nm range were prepared, immobilized on activated carbon and further tested, at low base concentration, in the catalytic oxidation of 5-hydroxymethyl furfural (HMF) to 2,5-furandicarboxylic acid (FDCA). Gold particles size variation has no influence on HMF conversion but significantly affects product...

A series of CexZr1-xO2 supports with different Ce/Zr molar ratios were utilized for the preparation of gold catalyst used in the selective oxidation of 5-hydroxymethyl-2-furfural to 2,5-furandicarboxylic acid. The used method of gold deposition allows the preparation of gold particles with homogeneous size and shape distribution, a formulation...

A series of gold colloids were prepared and immobilized on commercial activated carbon. The influence of the colloid preparation and stability were studied and related to the gold particle size in the final catalyst. The catalysts show an important activity in the glucose to gluconic acid oxidation reaction, leading to gluconic acid yield close...

Two different approaches are proposed in this work in order to study the influence of the ionic liquid presence in the reaction of glucose oxidation by H2O2 in mild conditions. The ionic liquids are applied either as a solvent by using homogeneous Mo based catalyst, [Mo(O)(O2)2(H2O)n] complex, or by using it as an integral part of a...

In this work, carbon nanofibers (CNFs) have been successfully functionalized by using different approaches and finally used for the preparation of Ru based catalysts. The organometallic approach has been demonstrated to be suitable for CNF functionalization, leading to well-defined Ru NPs (by adding organosilane, amino or mercapto...