Promoted Hexagonal Tungsten Bronzes as Selective Catalysts in the Aerobic Transformation of Alcohols: Glycerol and Methanol

Microemulsion Derived Titania Nanospheres: An Improved Pt Supported Catalyst for Glycerol Aqueous Phase Reforming

Glycerol aqueous phase reforming (APR) produces hydrogen and interesting compounds at relatively mild temperatures. Among APR catalysts investigated in literature, little attention has been given to Pt supported on TiO₂. Therefore, herein we propose an innovative titania support which can be obtained through an optimized microemulsion technique. This procedure provided high surface area titania nanospheres, with a peculiar high density of weak acidic sites. The material was tested in the catalytic glycerol APR after Pt deposition. A mechanism hypothesis was drawn, which evidenced the pathways giving the main products. When compared with a commercial TiO₂ support, the synthetized titania provided higher hydrogen selectivity and glycerol conversion thanks to improved catalytic activity and ability to prompt consecutive dehydrogenation reactions. This was correlated to an enhanced cooperation between Pt nanoparticles and the acid sites of the support.

Continuous Flow Upgrading of Selected C2-C6 Platform Chemicals Derived from Biomass

The ever increasing industrial production of commodity and specialty chemicals inexorably depletes the finite primary fossil resources available on Earth. The forecast of population growth over the next 3 decades is a very strong incentive for the identification of alternative primary resources other than petro-based ones. In contrast with fossil resources, renewable biomass is a virtually inexhaustible reservoir of chemical building blocks. Shifting the current industrial paradigm from almost exclusively petro-based resources to alternative bio-based raw materials requires more than vibrant political messages; it requires a profound revision of the concepts and technologies on which industrial chemical processes rely. Only a small fraction of molecules extracted from biomass bears significant chemical and commercial potentials to be considered as ubiquitous chemical platforms upon which a new, bio-based industry can thrive. Owing to its inherent assets in terms of unique process experience, scalability, and reduced environmental footprint, flow chemistry arguably has a major role to play in this context. This review covers a selection of C₂ to C₆ bio-based chemical platforms with existing commercial markets including polyols (ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,4-butanediol, xylitol, and sorbitol), furanoids (furfural and 5-hydroxymethylfurfural) and carboxylic acids (lactic acid, succinic acid, fumaric acid, malic acid, itaconic acid, and levulinic acid). The aim of this review is to illustrate the various aspects of upgrading bio-based platform molecules toward commodity or specialty chemicals using new process concepts that fall under the umbrella of continuous flow technology and that could change the future perspectives of biorefineries.

Al2O3-Supported W–V–O bronze catalysts for oxidative dehydrogenation of ethane

Vanadium-containing hexagonal tungsten bronze (HTB) structures supported on Al₂O₃ are more selective to ethylene during ethane ODH than supported vanadium oxides.

W–Nb–O oxides with tunable acid properties as efficient catalysts for the transformation of biomass-derived oxygenates in aqueous systems

The control of Nb incorporation in W–Nb–O system leads to tailored Brönsted/Lewis acid properties for the selective transformation of either glycerol or aqueous mixtures of short chain oxygenates into value added products.

New process for producing butane-2,3-dione by oxidative dehydrogenation of 3-hydroxybutanone

Reaction of 3-hydroxybutanone in air has been studied with and without a catalyst under atmospheric pressure and at temperatures between 523 and 673 K.

Structure-Reactivity Correlations in Vanadium-Containing Catalysts for One-Pot Glycerol Oxidehydration to Acrylic Acid

The design of suitable catalysts for the one-pot conversion of glycerol into acrylic acid (AA) is a complex matter, as only fine-tuning of the redox and acid properties makes it possible to obtain significant yields of AA. However, fundamental understanding behind the catalytic phenomenon is still unclear. Structure-reactivity correlations are clearly behind these results, and acid sites are involved in the dehydration of glycerol into acrolein with vanadium as the main (or only) redox element. For the first time, we propose an in-depth study to shed light on the molecular-level relations behind the overall catalytic results shown by several types of V-containing catalysts. Different multifunctional catalysts were synthesized, characterized (>X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, temperature-programmed reduction, and temperature-programmed desorption of ammonia), and tested in a flow reactor. Combining the obtained results with those acquired from an in situ FTIR spectroscopy study with acrolein (a reaction intermediate), it was possible to draw conclusions on the role played by the various physicochemical features of the different oxides in terms of the adsorption, surface reactions, and desorption of the reagents and reaction products.