Effect of sodium propionate as a stabilizer on the catalytic activity of Pt/C catalysts for d-glucose hydrogenation

Chemocatalytic value addition of glucose without carbon-carbon bond cleavage/formation reactions: an overview

As the monomeric unit of the abundant biopolymer cellulose, glucose is considered a sustainable feedstock for producing carbon-based transportation fuels, chemicals, and polymers. The chemocatalytic value addition of glucose can be broadly classified into those involving C-C bond cleavage/formation reactions and those without. The C6 products obtained from glucose are particularly satisfying because their syntheses enjoy a 100% carbon economy. Although multiple derivatives of glucose retaining all six carbon atoms in their moiety are well-documented, they are somewhat dispersed in the literature and never delineated coherently from the perspective of their carbon skeleton. The glucose-derived chemical intermediates discussed in this review include polyols like sorbitol and sorbitan, diols like isosorbide, furanic compounds like 5-(hydroxymethyl)furfural, and carboxylic acids like gluconic acid. Recent advances in producing the intermediates mentioned above from glucose following chemocatalytic routes have been elaborated, and their derivative chemistry highlighted. This review aims to comprehensively understand the prospects and challenges associated with the catalytic synthesis of C6 molecules from glucose.

Effects of chlorinated Pd precursors and preparation methods on properties and activity of Pd/TiO2 catalysts

We investigated the effects of Pd precursors and preparation methods on the physicochemical properties and performance of Pd/TiO₂ catalysts in the photocatalytic degradation of methyl violet. To confirm the influence of the precursors, Pd/TiO₂ catalysts were prepared via chemical reduction (CR) using four different Pd precursors. Additionally, to determine the effects of preparation methods, Pd/TiO₂ catalysts were fabricated using K₂PdCl₄ precursor via three different methods: CR, deposition-precipitation (DP), and impregnation. The CO chemisorption results showed that the catalyst prepared via DP using the K₂PdCl₄ precursor, i.e., Pd/TiO₂_K_DP, displayed the highest Pd dispersion of 12.42% owing to the stable formation of Pd(OH)₂, which strongly interacted with the -OH groups on the TiO₂ support. Although the catalyst prepared via CR using the Pd(NH₃)₄Cl₂·H₂O (PA) precursor, i.e., Pd/TiO₂_PA_CR, had the lowest Pd dispersion of 0.7%, it exhibited the highest absorption of 26% after 30 min in the dark. It was found that high Pd²⁺/Pd⁰ ratio in dark conditions adversely affected the absorption of MV owing to electrostatic repulsion between the cationic dyes and metal nanoparticles. However, the Pd dispersion and the specific surface area played a key role in the photocatalytic activity under UV irradiation. Pd/TiO₂_K_CR with higher Pd dispersion showed the highest photocatalytic activity and reaction rate of 0.0212 min^-1.

Efficient Sorbitol Producing Process through Glucose Hydrogenation Catalyzed by Ru Supported Amino Poly (Styrene-co-Maleic) Polymer (ASMA) Encapsulated on γ-Al2O3

In this work, a core-shell-like sphere ruthenium catalyst, named as 5%Ru/γ-Al2O3@ASMA, has been successfully synthesized through impregnating the ruthenium nanoparticles (NPs) on the surface of the amino poly (styrene-co-maleic) polymer (ASMA) encapsulating γ-Al2O3 pellet support. The interaction between the Ru cations and the electro-donating polymer shell rich in hydroxyl and amino groups through the coordination bond would guarantee that the Ru NPs can be highly dispersed and firmly embedded on the surface of the support. In addition, the solid sphere γ-Al2O3 pellet could serve as the core to support the resulted catalysts applied in the flow process in a trickle bed reactor to promote the productivity. The resulted catalyst 5%Ru/γ-Al2O3@ASMA can be applied efficiently in the glucose hydrogenation and presents a steadfast sorbitol yield of almost 90% both in batch reactor and the trickle bed reactor, indicating the potential feasibility of the core-shell-like catalyst in the efficient production of sorbitol.