Search

A simple non-precious-metal catalyst system based on costeffective and ubiquitously available MnO2, NaHCO3, and molecular oxygen was used to convert 5-hydroxymethylfurfural (HMF) to 2,5-difurandicarboxylic acid (FDCA) as a bioplastics precursor in 91 % yield. The MnO2 catalyst could be recovered by simple filtration and reused several times. The present system was also applicable to the aerobic oxidation of other biomass-derived substrates and the gram-scale oxidation of HMF to FDCA, in which 2.36 g (86 % yield) of the analytically pure FDCA could be isolated. [ABSTRACT FROM AUTHOR]

Catalytic conversion of glycerol to valuable chemicals has been recognized as an attractive and challenging reaction in biorefinery. In this paper, we demonstrated that a combined catalyst of Pt nanoparticles and TiO2 worked as a highly active catalyst for the one-pot conversion of glycerol to lactic acid in water. The yield of lactic acid reached 63 % under oxygen atmosphere without the use of any additives such as strong bases, and the catalyst could be reused without significant loss of the catalytic performance. The mechanistic studies revealed that Pt nanoparticles on TiO2 selectively oxidized glycerol to C3 aldehyde/ketone, and Lewis acid sites on TiO2 smoothly promoted the dehydration and rehydration/rearrangement reactions of the intermediates to produce lactic acid efficiently. [ABSTRACT FROM AUTHOR]

Efficient hydrolytic hydrogenation of cellulose to sugar alcohols under low H2 pressures has remained a challenge. This article deals with the conversion of cellulose by using a carbon-supported Ru catalyst under H2 pressures as low as 0.7-0.9 MPa (absolute pressure at room temperature). Kinetic studies revealed that the Ru catalyst not only enhances the hydrolysis of cellulose to glucose and hydrogenation of glucose to sugar alcohols (sorbitol and mannitol), but also the degradation of sugar alcohols to C2-C6 polyols and gasses. The degradation path limits the total yield of sugar alcohols to less than 40 %. The yield of sugar alcohols is theoretically improved by increasing the ratio of the reaction rates of the cellulose hydrolysis, which is the rate-determining step in the reaction, to the decomposition. Thus, a mix-milling pretreatment of cellulose and the Ru catalyst together selectively accelerated the hydrolysis step and raised the yield up to 68 %, whereas the addition of acids in the cellulose conversion was less effective as a result of promotion of side-reactions. These results demonstrate superior applicability of the mix-milling treatment in the depolymerization of cellulose to its monomers. [ABSTRACT FROM AUTHOR]

Abstract: A manganese oxides supported on cerium(IV) oxide MnO x /CeO2 precatalyst by wetness impregnation with manganese(II) acetate and cerium(IV) oxide. A Ru/MnO x /CeO2 catalyst was prepared by wetness impregnation of MnO x /CeO2 precatalyst with aqueous solution of ruthenium(III) chloride. The Ru/MnO x /CeO2 catalyst has high catalytic activities for the oxidation of alcohols to the corresponding carbonyl compounds. Especially, the advantage of the present catalyst is the smooth oxidation of alcohols at 300K under molecular oxygen atmosphere. [Copyright &y& Elsevier]

The Back Cover picture shows the selective oxidation of 5‐hydroxymethylfurfural to 2,5‐furandicarboxylic acid as a bioplastics precursor. The reaction is performed using a simple non‐precious metal catalyst system based on cost‐effective and ubiquitously available manganese oxide, sodium bicarbonate, and molecular oxygen. More details can be found in the Communication by Hayashi et al. on page 654 in Issue 4, 2017 (DOI: 10.1002/cssc.201601443). [ABSTRACT FROM AUTHOR]

Ammonia is an extremely important storage and transport medium for renewable energy, and technology is expected to produce it on demand and onsite using renewable energy. Applying a DC (direct current) to a solid catalyst layer with semiconducting properties makes ammonia synthesis highly efficient, even at low temperatures (approximately 400 K). In this process, oxide supports with semiconducting properties play important roles as metal supports and conduction fields for electrons and protons. The influence of the degree of particle aggregation on the support properties and ammonia synthesis using an electric field was evaluated for CeO 2 , which is the best material for this purpose because of its semiconducting properties. The results showed that controlling the aggregation structure of the crystalline particles could significantly influence the surface conductivity of protons and electrons; thus, the activity could be largely controlled. The Ru-CeO 2 interaction could also be controlled by changing the crystallinity, which suppressed the aggregation of the supported Ru and significantly improved the ammonia synthesis activity using an electric field at low temperatures., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)