Synergistic catalysis within TEMPO-functionalized periodic mesoporous organosilica with bridge imidazolium groups in the aerobic oxidation of alcohols

Anchoring TEMPO within the nanospaces of a PMO with bridged imidazolium groups led to an powerful bifunctional catalyst (TEMPO@PMO-IL-Br), which showed enhanced activity in the metal-free aerobic oxidation of alcohols.

Catalytic aerobic oxidation of 5-hydroxymethylfurfural into 2,5-diformylfuran over VO2+and Cu2+immobilized on amino-functionalized core–shell magnetic Fe3O4@SiO2

Amino modified Fe₃O₄@SiO₂(Fe₃O₄@SiO₂–NH₂) was used to immobilize Cu²⁺and VO²⁺for preparing Fe₃O₄@SiO₂–NH₂–Cu²⁺and Fe₃O₄@SiO₂–NH₂–VO²⁺catalysts.

Aerobic selective oxidation of 5-hydroxymethyl-furfural over nitrogen-doped graphene materials with 2,2,6,6-tetramethylpiperidin-oxyl as co-catalyst

N-doped graphene materials were prepared via thermal treatment of graphene oxide in flowing NH₃, and their catalytic performance was tested in aerobic oxidation of 5-hydroxymethy-furfural.

Copper-zinc alloy nanopowder: a robust precious-metal-free catalyst for the conversion of 5-hydroxymethylfurfural

Noble-metal-free copper-zinc nanoalloy (<150 nm) is found to be uniquely suited for the highly selective catalytic conversion of 5-hydroxymethylfurfural (HMF) to potential biofuels or chemical building blocks. Clean mixtures of 2,5-dimethylfuran (DMF) and 2,5-dimethyltetrahydrofuran (DMTHF) with combined product yields up to 97 % were obtained at 200-220 °C using 20-30 bar H2 . It is also possible to convert 10 wt % HMF solutions in CPME, with an excellent DMF yield of 90 %. Milder temperatures favor selective (95 %) formation of 2,5-furandimethanol (FDM). The one-pot conversion of fructose to valuable furan-ethers was also explored. Recycling experiments for DMF production show remarkable catalyst stability. Transmission electron microscopy (TEM) characterization provides more insight into morphological changes of this intriguing class of materials during catalysis.

Catalytic etherification of hydroxyl compounds to methyl ethers with 1,2-dimethoxyethane

1,2-Dimethoxyethane is explored as a new useful etherification agent for the 12-tungstophosphoric acid-catalyzed synthesis of methyl ethers from biomass-derived hydroxyl compounds.

Plant-mediated synthesis of Au–Pd alloy nanoparticles supported on MnO2nanostructures and their application toward oxidation of 5-(hydroxymethyl)furfural

The bio-reduction of Au(iii) and Pd(ii) was first applied to the loading process. Au–Pd/MnO₂was first applied in oxidation of HMF. The effects of Au–Pd molar ratio and the support morphology on the catalysis were discussed.

Ruthenium complex immobilized on poly(4-vinylpyridine)-functionalized carbon-nanotube for selective aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

Ruthenium complex, immobilized on poly(4-vinylpyridine)-functionalized carbon-nanotube, shows excellent catalytic performance towards selective aerobic oxidation of biomass-based 5-hydroxymethylfurfural to 2,5-diformylfuran.

Iron oxide encapsulated by ruthenium hydroxyapatite as heterogeneous catalyst for the synthesis of 2,5-diformylfuran

Magnetic γ-Fe2 O3 nanocrystallites encapsulated by hydroxyapatite (HAP), HAP@γ-Fe2 O3 , were prepared followed by cation exchange of Ca(2+) on the external HAP surface with Ru(3+) to give the γ-Fe2 O3 @HAP-Ru catalyst. The structure of the as-prepared catalyst was characterized, and its catalytic activity was studied in the aerobic oxidation of 5-hydroxymethylfurfural (HMF). γ-Fe2 O3 @HAP-Ru showed a high catalytic activity for the aerobic oxidation of HMF into 2,5-diformylfuran (DFF). A high DFF yield of 89.1 % with an HMF conversion of 100% was obtained after 4 h at 90 °C. Importantly, the synthesis of DFF from fructose was realized by two consecutive steps. The dehydration of fructose in the presence of a magnetic acid catalyst (Fe3 O4 @SiO2-SO3 H) produced HMF in a yield of 90.1%. Then the Fe3 O4 @SiO2 SO3 H catalyst was removed from the reaction solution with a permanent magnet, and HMF in the resulting solution was further oxidized to DFF with a yield of 79.1% based on fructose. The synthesis of DFF from fructose by two steps avoids the tedious separation of the intermediate HMF, which saves time and energy.

One-pot, one-step synthesis of 2,5-diformylfuran from carbohydrates over Mo-containing Keggin heteropolyacids

In this work, a one-pot strategy for directly converting fructose into 2,5-diformylfuran (DFF) over Mo-containing Keggin heteropolyacids (HPAs) in open air is developed. H3 PMo12 O40 HPA is found to show high activity and selectivity to the formation of DFF owing to its higher Brønsted acidity and moderate redox potential. The partial substitution of the H(+) in H3 PMo12 O40 with Cs(+) leads to the heterogenization of the HPA by forming its cesium salts Csx H3-x PMo12 (x=0.5, 1.5, and 2.5). A satisfactory yield of 69.3% to DFF is obtained over Cs0.5 H2.5 PMo12 polyoxometalate after deliberate optimization of the reaction conditions. The heterogenized polyoxometalate could be recycled and reused without significant loss of catalytic activity for five runs. The produced DFF could be separated from the resulting mixture by an adsorption-desorption method using activated carbon as the adsorbent and furfural as the desorbent. A highest isolated yield of 58.2% is obtained.

Zeolite Supported Ionic Liquid Catalyst for the Synthesis of Nano-Cellulose from Palm Tree Biomass

Nanocellulose promises to be a very versatile material having wide range of biomedical and biotechnological applications including tissue engineering, drug delivery, wound dressings, medical implants, food, cosmetics, paper and textiles. The current methods for the synthesis of nanocellulose involve harsh chemical treatments which are perpetually hazardous to human and environment. Catalytic synthesis of nanocellulose might be a green approach. Among the various types of catalyst, ionic liquids, which are composed of both cations and anions and have low or negligible vapor pressure, are particularly promising. Ionic liquids also exhibit a relatively wide electrochemically stable window, good electrical conductivity, high ionic mobility, a broad range of room temperature liquid compositions, selective dissolvability to many organic and inorganic materials, and excellent chemical and thermal stabilities. In contrast, zeolite catalysts have been used in petroleum refineries for the removal of sulfur. Zeolite catalysts are also important for the synthesis of bulk chemicals, fine and specialty chemicals, fuels and chemicals. Acidic and metal modified micro porous zeolite catalysts have been used in several commercial processes in petroleum industry, fuel components, abatement of exhaust gas emissions and biomass upgrading, pharmaceutical and fine chemical industries. Currently, zeolite catalysts are synthesized in powder form and to make them industrially useful, such catalysts have to be mixed with a binder and formulated in different shapes. This paper reviewed the introduction, preparation, synthesis and application of nanocellulose from lignocellulosic palm biomass.

Highly efficient aerobic oxidation of biomass-derived 5-hydroxymethyl furfural to produce 2,5-diformylfuran in the presence of copper salts

Based on the catalysis of copper salt, an efficient and selective oxidation of 5-hydroxymethyl furfural to 2,5-diformylfuran with molecular oxygen as the oxidant has been developed.

The microwave-assisted ionic liquid nanocomposite synthesis: platinum nanoparticles on graphene and the application on hydrogenation of styrene

The microwave-assisted nanocomposite synthesis of metal nanoparticles on graphene or graphite oxide was introduced in this research. With microwave assistance, the Pt nanoparticles on graphene/graphite oxide were successfully produced in the ionic liquid of 2-hydroxyethanaminium formate [HOCH2CH2NH3][HCO2]. On graphene/graphite oxide, the sizes of Pt nanoparticles were about 5 to 30 nm from transmitted electron microscopy (TEM) results. The crystalline Pt structures were examined by X-ray diffraction (XRD). Since hydrogenation of styrene is one of the important well-known chemical reactions, herein, we demonstrated then the catalytic hydrogenation capability of the Pt nanoparticles on graphene/graphite oxide for the nanocomposite to compare with that of the commercial catalysts (Pt/C and Pd/C, 10 wt.% metal catalysts on activated carbon from Strem chemicals, Inc.). The conversions with the Pt nanoparticles on graphene are >99% from styrene to ethyl benzene at 100°C and under 140 psi H2 atmosphere. However, ethyl cyclohexane could be found as a side product at 100°C and under 1,520 psi H2 atmosphere utilizing the same nanocomposite catalyst.