Zhongtian Du

Conversion of furfural into cyclopentanone over Ni–Cu bimetallic catalysts

The conversion of furfural into cyclopentanone over Ni–Cu bimetallic catalysts was studied under hydrogen atmosphere. Furfuryl alcohol, 4-hydroxy-2-cyclopentenone and 2-cyclopentenone were verified as three key intermediates. Rearrangement of the furan ring was independent of hydrogenation, starting from furfuryl alcohol rather than furfural. The opening and closure of the furan ring were closely related to the attack of a H2O molecule on the 5-position of furfuryl alcohol. Prior hydrogenation of the aldehyde group accounted for the different reactivity of furfural and furfuryl alcohol. The high selectivity of cyclopentanone was ascribed to the presence of 2-cyclopentenone.

Gold Nanoclusters Confined in a Supercage of Y Zeolite for Aerobic Oxidation of HMF under Mild Conditions

Au nanoclusters with an average size of approximately 1 nm size supported on HY zeolite exhibit a superior catalytic performance for the selective oxidation of 5-hydroxymethyl-2-furfural (HMF) into 2,5-furandicarboxylic acid (FDCA). It achieved >99 % yield of 2,5-furandicarboxylic acid in water under mild conditions (60 °C, 0.3 MPa oxygen), which is much higher than that of Au supported on metal oxides/hydroxide (TiO2 , CeO2 , and Mg(OH)2 ) and channel-type zeolites (ZSM-5 and H-MOR). Detailed characterizations, such as X-ray diffraction, transmission electron microscopy, N2 -physisorption, and H2 -temperature-programmed reduction (TPR), revealed that the Au nanoclusters are well encapsulated in the HY zeolite supercage, which is considered to restrict and avoid further growing of the Au nanoclusters into large particles. The acidic hydroxyl groups of the supercage were proven to be responsible for the formation and stabilization of the gold nanoclusters. Moreover, the interaction between the hydroxyl groups in the supercage and the Au nanoclusters leads to electronic modification of the Au nanoparticles, which is supposed to contribute to the high efficiency in the catalytic oxidation of HMF to FDCA.

Oxidation of 5-hydroxymethylfurfural to maleic anhydride with molecular oxygen

5-Hydroxymethylfurfural (HMF) was converted to maleic anhydride in 52% yield via selective oxidation with molecular oxygen using VO(acac)2 as catalyst in liquid phase.

Aerobic oxidation of primary aliphatic alcohols over bismuth oxide supported platinum catalysts in water

Catalytic oxidation of non-activated aliphatic alcohols with molecular oxygen is rather challenging, especially in an aqueous medium in the absence of an additional base. Bismuth is usually used as a promoter of platinum-based catalysts. In this work, bismuth oxide was explored as a support, and Pt0 nanoparticles supported on bismuth oxide (Pt/Bi2O3) exhibited high activity for aerobic oxidation of n-butanol using water as a solvent in the absence of an additional base under optimized conditions. Besides n-butanol, liquid primary aliphatic alcohols with low solubility in water could also be smoothly oxidized into the corresponding carbonyl compounds with molecular oxygen. Pt/Bi2O3 reduced by H2 at about 200 °C showed the highest activity for aerobic oxidation of n-butanol. At this temperature, platinum oxide was reduced to Pt0 and bismuth oxide could be reduced partially which might change the surface property of bismuth oxide.

Synthesis and properties of furan-based imine-linked porous organic frameworks

Furan-based porous organic frameworks (FOFs) were prepared by condensation of biomass-derived 2,5-diformylfuran (DFF) and diamines via the formation of imine linkages, which are insoluble in water and common organic solvents and can keep stable around 300 °C under N2 atmosphere. The materials obtained by DFF being condensed with nonlinear diamines show higher specific surface areas and micropore volumes than that of with linear diamines. In the adsorption of CO2, the capacity of the FOFs largely depends on their specific surface areas and micropore volumes.

Selective oxidative C–C bond cleavage of a lignin model compound in the presence of acetic acid with a vanadium catalyst

Selective transformation of lignin into value-added aromatics is highly attractive and rather challenging. Catalytic oxidative degradation provides a promising approach to obtain aromatics from lignin while preserving the benzene units. In this study, vanadium-catalyzed aerobic oxidation of 2-phenoxy-1-phenylethanol was studied as a lignin model compound. The solvent played a significant role in the distribution of oxidation products. In the presence of acetic acid, oxidative C–C bond cleavage was preferred, while oxidation products via C–H bond cleavage were rather limited. A one-electron transfer process was involved in the oxidation reaction. The occurrence of vanadium(V) was detected, and the carboxylic group could coordinate to vanadium(V) through exchange with the acetylacetonato ligand during oxidation in the presence of acetic acid.

Biphasic Catalytic Conversion of Fructose by Continuous Hydrogenation of HMF over a Hydrophobic Ruthenium Catalyst

The production of chemicals directly from sugars is an important step in biomass conversion. Herein, tetrahydro-2,5-furandimethanol (THFDM), obtained from fructose, is formed by using a combination of acid and hydrophobic Ru/SiO2 in a water/cyclohexane biphasic system. Two key factors enable the high selectivity towards THFDM: modifying the hydrogenation catalyst so that it has hydrophobic properties, and the continuous hydrogenation of generated 5-(hydroxymethyl)furfural in the cyclohexane phase. Moreover, the selectivity towards THFDM is found to depend strongly on the acid catalyst used.

Gold nanoparticles confined in the interconnected carbon foams with high temperature stability

Gold nanoparticle-carbon foam composites with highly-dispersed gold nanoparticles confined in the cavities were prepared. The gold nanoparticles are effectively separated from each other by permeable carbon shells, which show high temperature stability and were fully accessible to the substrate.

Synergistic effect of vanadium–phosphorus promoted oxidation of benzylic alcohols with molecular oxygen in water

The synergistic effect of vanadium–phosphorus in aqueous solution is crucial to ensure high efficiency for oxidation of benzylic alcohols with molecular oxygen in water catalyzed by VOPO4/TEMPO (2,2,6,6-tetramethylpiperidyl-1-oxy).

Organocatalytic oxidative dehydrogenation of dihydroarenes by dioxygen using 2,3-dichloro-5,6-dicyano-benzoquinone (DDQ) and NaNO2.

The oxidative dehydrogenation of dihydroarenes catalyzed by 2,3-dichloro-5,6-dicyano-benzoquinone(DDQ) and NaNO2 with dioxygen is reported. The combination of DDQ and NaNO2 showed high efficiency and high selectivity, compared with other benzoquinones and anthraquinones, e.g., >99% conversion of 9,10-dihydroanthracene with 99% selectivity for anthracene can be obtained at 120 °C under 1.3 MPa O2 for 8 h. Excellent results were achieved in the oxidative dehydrogenation of variety of dihydroarenes.