5-Hydroxymethylfurfural: A key intermediate for efficient biomass conversion

Biomass has been widely accepted as a "zero-emission" energy carrier to take place fossil fuels, while its catalytic conversion is still limited by low efficiency of carbon atoms. Biomass conversion via 5-hydroxymethylfurfural (HMF) as a platform chemical is highly attractive because almost all carbon atoms could be retained in the downstream chemicals under mild reaction conditions. Here we summarize recent fundamental researches and industrial progresses on all involved processes including biomass degradation to hexoses, HMF formation, hydrogenation and oxidation of HMF. (C) 2015 Science Press and Dalian Institute of Chemical Physics. All rights reserved

Fabrication of Nitrogen-Modified Annealed Nanodiamond with Improved Catalytic Activity

Annealed ultra­dispersed nanodiamond (ADD) with sp² curved concentric graphitic shells is an interesting hybrid material consisting of the remarkable surface properties of graphene-based nanomaterials and the intrinsic properties of a diamond core. In this case, based on its specific properties and surface oxygen functional groups, nitrogen-modified ADD powders have been tunably synthesized <i>via</i> three different preparation methods in a calcination treatment process. The detailed formation and dynamic behaviors of the nitrogen species on the modified ADD during the preparation process are revealed by elemental analysis, X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption. Moreover, we study the catalytic performance on the metal-free nitrogen-modified ADD catalysts by means of selective oxidation of benzylic alcohols as a probe reaction. The results indicate that the modified ADD catalysts exhibit a higher catalytic activity than pristine ADD. By correlating XPS data with catalytic measurements, we conclude that the pyridinic nitrogen species plays a pivotal role in the catalytic reaction. Our work provides valuable information on the design of modified carbon materials with more excellent properties

Metal-Free Oxidation of Glycerol over Nitrogen-Containing Carbon Nanotubes

Nitrogen rich carbon nanotubes have been used as a metal free catalyst for the conversion of glycerol into dihydroxyacetone using tert-butyl hydroperoxide as an oxidant. Pyridine nitrogen groups embedded in a carbon matrix are identified as active sites for the reaction. Computational studies have demonstrated that oxidation of pyridine groups to pyridine oxime followed by hydrogen abstraction from secondary alcohol is likely responsible for the oxidation process

Efficient functionalization of multi-walled carbon nanotubes by nitrogen dioxide

Nitrogen dioxide (NO2) as an oxidative agent can efficiently react with multi-walled carbon nanotubes (CNTs) and sequentially introduces large quantities of oxygen functional groups on the surface. The produced NO can be easily oxidized by O2 into NO2, achieving an almost close cycle of NOx. NO2 is more favorable to generate active qunione groups on CNTs surface and improve the specific surface area of CNTs. The NO2-treated CNTs show the superior catalytic performance for oxidative dehydrogenation of propane. This work provides an applicable and efficient method for the mass functionalization of CNTs and other carbon materials

Valorisation of Biomass Derived Furfural and Levulinic Acid by Highly Efficient Pd@ND Catalyst

Palladium nanoparticles deposited on nanodiamonds (Pd/ND) have been demonstrated as efficient catalyst for the liquid phase hydrogenation of furfural and levulinic acid to furfuryl alcohol and gamma-valerolactone, respectively. The activity of the catalyst was compared to other counterparts such as Pd on activated carbon, graphene and carbon nanotubes respectively, and was found to depend on surface carbonyl groups. The highest stability of Pd/ND seems to be related to the presence of a higher amount of sp(3) carbon compared to the other supports. The developed methodology will prove beneficial for valorization of biomass derived furfural and levulinic acid in the future biorefineries

From microporous regular frameworks to mesoporous materials with ultrahigh surface area: Dynamic reorganization of porous polymer networks

High surface area organic materials featuring both micro- and mesopores were synthesized under ionothermal conditions via the formation of polyaryltriazine networks. While the polytrimerization of nitriles in zinc chloride at 400 °C produces microporous polymers, higher reaction temperatures induce the formation of additional spherical mesopores with a narrow dispersity. The nitrogen-rich carbonaceous polymer materials thus obtained present surface areas and porosities up to 3300 m2 g−1 and 2.4 cm3 g−1, respectively. The key point of this synthesis relies on the occurrence of several high temperature polymerization reactions, where irreversible carbonization reactions coupled with the reversible trimerization of nitriles allow the reorganization of the dynamic triazine network. The ZnCl2 molten salt fulfills the requirement of a high temperature solvent, but is also required as catalyst. Thus, this dynamic polymerization system provides not only highly micro- and mesoporous materials, but also allows controlling the pore structure in amorphous organic materials