Lignin is the only large-volume renewable source of aromatic chemicals. Efficient depolymerization and deoxygenation of lignin while retaining the aromatic functionality are attractive but extremely ...challenging. Here we report the selective production of arenes via direct hydrodeoxygenation of organosolv lignin over a porous Ru/Nb
O
catalyst that enabled the complete removal of the oxygen content from lignin. The conversion of birch lignin to monomer C
-C
hydrocarbons is nearly quantitative based on its monomer content, with a total mass yield of 35.5 wt% and an exceptional arene selectivity of 71 wt%. Inelastic neutron scattering and DFT calculations confirm that the Nb
O
support is catalytically unique compared with other traditional oxide supports, and the disassociation energy of C
-OH bonds in phenolics is significantly reduced upon adsorption on Nb
O
, resulting in its distinct selectivity to arenes. This one-pot process provides a promising approach for improved lignin valorization with general applicability.
The integration of luminescence and chirality in easy-scalable metal-organic frameworks gives rise to the development of advanced luminescent sensors. To date, the synthesis of chiral metal-organic ...frameworks is poorly predictable and their chirality primarily originates from components that constitute the frameworks. By contrast, the introduction of chirality into the pores of metal-organic frameworks has not been explored to the best of our knowledge. Here, we demonstrate that chirality can be introduced into an anionic Zn-based metal-organic framework via simple cation exchange, yielding dual luminescent centers comprised of the ligand and Tb
ions, accompanied by a chiral center in the pores. This bifunctional material shows enantioselectivity luminescent sensing for a mixture of stereoisomers, demonstrated for Cinchonine and Cinchonidine epimers and amino alcohol enantiomers, from which the quantitative determination of the stereoisomeric excess has been obtained. This study paves a pathway for the design of multifunctional metal-organic framework systems as a useful method for rapid sensing of chiral molecules.
Being the only sustainable source of organic carbon, biomass is playing an ever-increasingly important role in our energy landscape. The conversion of renewable lignocellulosic biomass into liquid ...fuels is particularly attractive but extremely challenging due to the inertness and complexity of lignocellulose. Here we describe the direct hydrodeoxygenation of raw woods into liquid alkanes with mass yields up to 28.1 wt% over a multifunctional Pt/NbOPO4 catalyst in cyclohexane. The superior performance of this catalyst allows simultaneous conversion of cellulose, hemicellulose and, more significantly, lignin fractions in the wood sawdust into hexane, pentane and alkylcyclohexanes, respectively. Investigation on the molecular mechanism reveals that a synergistic effect between Pt, NbOx species and acidic sites promotes this highly efficient hydrodeoxygenation of bulk lignocellulose. No chemical pretreatment of the raw woody biomass or separation is required for this one-pot process, which opens a general and energy-efficient route for converting raw lignocellulose into valuable alkanes.
Supramolecular interactions are fundamental to host-guest binding in many chemical and biological processes. Direct visualization of such supramolecular interactions within host-guest systems is ...extremely challenging, but crucial to understanding their function. We report a comprehensive study that combines neutron scattering, synchrotron X-ray and neutron diffraction, and computational modelling to define the detailed binding at a molecular level of acetylene, ethylene and ethane within the porous host NOTT-300. This study reveals simultaneous and cooperative hydrogen-bonding, π···π stacking interactions and intermolecular dipole interactions in the binding of acetylene and ethylene to give up to 12 individual weak supramolecular interactions aligned within the host to form an optimal geometry for the selective binding of hydrocarbons. We also report the cooperative binding of a mixture of acetylene and ethylene within the porous host, together with the corresponding breakthrough experiments and analysis of adsorption isotherms of gas mixtures.
Abstract
The development of precious-metal-free catalysts to promote the sustainable production of fuels and chemicals from biomass remains an important and challenging target. Here, we report the ...efficient hydrogenolysis of biomass-derived 5-hydroxymethylfurfural to 2,5-dimethylfuran over a unique core-shell structured catalyst, Co@CoO that affords the highest productivity among all catalysts, including noble-metal-based catalysts, reported to date. Surprisingly, we find that the catalytically active sites reside on the shell of CoO with oxygen vacancies rather than the metallic Co. The combination of various spectroscopic experiments and computational modelling reveals that the CoO shell incorporating oxygen vacancies not only drives the heterolytic cleavage, but also the homolytic cleavage of H
2
to yield more active H
δ−
species, resulting in the exceptional catalytic activity. Co@CoO also exhibits excellent activity toward the direct hydrodeoxygenation of lignin model compounds. This study unlocks, for the first time, the potential of simple metal-oxide-based catalysts for the hydrodeoxygenation of renewable biomass to chemical feedstocks.
The conversion of cellulose from renewable biomass into the key platform chemical, 5-hydroxymethylfurfural (HMF), is of fundamental importance to the production of numerous bioproducts and biofuels. ...Various acidic catalysts have been developed for this process; however, most systems suffer from low efficiency and poor sustainability. Here, we report an acid-free conversion of cellulose into HMF in a biphasic system of tetrahydrofuran/concentrated seawater. The yield of HMF reached 48.6%, and this system has excellent reusability and sustainability. We found that the chloridions (Cl–) can promote the isomerization of glucose via a 1,2-hydride shift path and accelerate the dehydration of fructose, thus driving the selective formation of HMF. This simple system is capable of converting raw biomass to furfural and HMF with the lignin residues transformed into useful alkanes via a sequential catalytic upgrading, paving a new economic-viable pathway for the full valorization of lignocellulosic biomass.
We report a record-high SO2 adsorption capacity of 12.3 mmol g–1 in a robust porous material, MFM-601, at 298 K and 1.0 bar. SO2 adsorption in MFM-601 is fully reversible and highly selective over ...CO2 and N2. The binding domains for adsorbed SO2 and CO2 molecules in MFM-601 have been determined by in situ synchrotron X-ray diffraction experiments, giving insights at the molecular level to the basis of the observed high selectivity.
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