The utilization of compounds from natural sources to prepare functional materials is of great importance. Herein, we describe for the first time the preparation of organic–inorganic hybrid catalysts ...by using natural phytic acid as building block. Zirconium phosphonate (Zr‐PhyA) was synthesized by reaction of phytic acid and ZrCl4 and was obtained as a mesoporous material with pore sizes centered around 8.5 nm. Zr‐PhyA was used to catalyze the mild and selective Meerwein–Ponndorf–Verley (MPV) reduction of various carbonyl compounds, e.g., of levulinic acid and its esters into γ‐valerolactone. Further studies indicated that both Zr and phosphate groups contribute significantly to the excellent performance of Zr‐PhyA.
All natural: Porous zirconium phosphonate (Zr‐PhyA) was synthesized simply by reaction of natural phytic acid (PhyA) and ZrCl4 and applied as a very efficient catalyst for the Meerwein–Ponndorf–Verley reduction of various carbonyl compounds. Both the Zr element and phosphate groups contributed significantly to the excellent catalytic performance of Zr‐PhyA.
Cyclohexanone and its derivatives are very important chemicals, which are currently produced mainly by oxidation of cyclohexane or alkylcyclohexane, hydrogenation of phenols, and alkylation of ...cyclohexanone. Here we report that bromide salt-modified Pd/C in H
O/CH
Cl
can efficiently catalyse the transformation of aromatic ethers, which can be derived from biomass, to cyclohexanone and its derivatives via hydrogenation and hydrolysis processes. The yield of cyclohexanone from anisole can reach 96%, and the yields of cyclohexanone derivatives produced from the aromatic ethers, which can be extracted from plants or derived from lignin, are also satisfactory. Detailed study shows that the Pd, bromide salt and H
O/CH
Cl
work cooperatively to promote the desired reaction and inhibit the side reaction. Thus high yields of desired products can be obtained. This work opens the way for production of ketones from aromatic ethers that can be derived from biomass.
Construction of N-substituted pyrrolidones from biomass-derived levulinic acid (LA) via reductive amination is a highly attractive route for biomass valorization. However, realizing this ...transformation using H2 as the hydrogen source under mild conditions is still very challenging. Herein, we designed porous TiO2 nanosheets-supported Pt nanoparticles (Pt/P-TiO2) as the heterogeneous catalyst. The prepared Pt/P-TiO2 was highly efficient for reductive amination of LA to produce various N-substituted pyrrolidones (34 examples) at ambient temperature and H2 pressure. Meanwhile, Pt/P-TiO2 showed good applicability for reductive amination of levulinic esters, 4-acetylbutyric acid, 2-acetylbenzoic acid, and 2-carboxybenzaldehyde. Systematic studies indicated that the strong acidity of P-TiO2 and the lower electron density of the Pt sites as well as the porous structure resulted in the excellent activity of Pt/P-TiO2.
The effect of water on CO2 hydrogenation to produce higher alcohols (C2–C4) was studied. Pt/Co3O4, which had not been used previously for this reaction, was applied as the heterogeneous catalyst. It ...was found that water and the catalyst had an excellent synergistic effect for promoting the reaction. High selectivity of C2–C4 alcohols could be achieved at 140 °C (especially with DMI (1,3‐dimethyl‐2‐imidazolidinone) as co‐solvent), which is a much lower temperature than reported previously. The catalyst could be reused at least five times without reducing the activity and selectivity. D2O and 13CH3OH labeling experiments indicated that water involved in the reaction and promoted the reaction kinetically, and ethanol was formed via CH3OH as an intermediate.
Water can enhance the synthesis of C2–C4 alcohols (C2+OH) from CO2 hydrogenation over Pt/Co3O4 significantly. The alcohols can be produced at a lower temperature with satisfactory activity and selectivity. DMI=1,3‐dimethyl‐2‐imidazolidinone.
The Zr-based metal-organic frameworks are generally prepared by solvothermal procedure. To overcome the slow kinetics of nucleation and crystallization of Zr-based metal-organic frameworks is of ...great interest and challenging. Here, we find that an ionic liquid as solvent can significantly accelerate the formation of Zr-based metal-organic frameworks at room temperature. For example, the reaction time is shortened to 0.5 h in 1-hexyl-3-methylimidazolium chloride for Zr-based metal-organic framework formation, while that in the conventional solvent N,N-dimethylformamide needs at least 120 h. The reaction mechanism was investigated in situ by
H nuclear magnetic resonance, spectroscopy synchrotron small angle X-ray scattering and X-ray absorption fine structure. This rapid, low-energy, and facile route produces Zr-based metal-organic framework nanoparticles with small particle size, missing-linker defects and large surface area, which can be used as heterogeneous catalysts for Meerwein-Ponndorf-Verley reaction.Crystallization kinetics of metal-organic frameworks in conventional organic solvents are usually very slow. Here, the authors show that an ionic liquid medium accelerates considerably the formation of Zr-based metal-organic frameworks that are active catalysts in the Meerwein-Ponndorf-Verley reaction.
Graphene and its derivatives have great potential for a variety of applications. The large-scale production of high-quality graphene using simple methods with cheap feedstocks is crucial for its wide ...applications. Glucose is an abundant and renewable carbon resource and FeCl
3
is a very cheap salt. Herein, we proposed a new method to prepare graphene that is simply composed of the dissolution of glucose and FeCl
3
in water, vaporization of water, and calcination. It was found that graphene with up to a few layers could be prepared and its electrical conductivity was similar to that of the graphene sheets synthesized using the chemical vapor deposition (CVD) method. Further studies indicated that FeCl
3
was the key to the generation of high-quality graphene, because it acted as both the template and catalyst, for the formation of graphene.
A novel method to prepare high-quality graphene is developed using simple calcination of a mixture of glucose and FeCl
3
.
The creep of shales affects the fracture conductivity, well production rate, and hence ultimate recovery of hydrocarbons from reservoir formations. This paper presents an experimental study of the ...creep characteristics of a shale softened by thermo-hydro-mechano-chemical (THMC) treatments that mimic the rock-fluid interactions affected by high temperature, high pressure, and hydraulic fracturing fluids. Microindentation was conducted to characterize the creep behavior of the THMC-treated specimens with the data analyzed by the Kelvin-Voigt (KV) and compliance methods, while X-ray diffraction and scanning electron microscopy were performed to analyze the compositional and microstructural changes respectively to aid interpretation of indentation measurements. Results show that the THMC treatments increase the creep rate by 46–162%, owing to the treatment-induced softening that varies with the treatment time and distance from the fluid-rock interface, while the Young's modulus and hardness decrease with both the THMC-treatment and creep durations. The softened zones become more viscous, as reflected by the decreased KV model's viscoelastic coefficients for the softened specimens. The higher creep rate of the softened zones is primarily attributed to the weakening in cementation bond and increase in microscale porosity due to the dissolution of carbonates. The findings help understand the mechanisms for creep deformation and pertinent proppant embedment in fractured shales, and hence can be used to predict shale gas production and optimize fracturing fluid additives and stimulants.
<正>Most manufactured products involve one or more chemical processes.We cannot imagine what our life will be like without the products produced by the chemical industry.However,on average,only ...a small proportion of the resources we take from the Earth is converted into the desired products in current chemical processes,and large amounts of wastes and hazardous materials are generated.How to supply humanity with enough food,
Tuning the activity of supported metals by changing the properties of supports is a highly attractive strategy to realize some important reactions in biomass transformation. Herein, Ru nanoparticles ...supported on montmorillonite (MMT) and hydroxyapatite (HAP), denoted as Ru/MMT and Ru/HAP, were prepared. It was found that the activity of the Ru catalysts for different routes to convert biomass-derived 2,5-hexanedione (2,5-HD) could be controlled by the support materials. Ru/MMT was active for the synthesis of dimethyltetrahydrofuran from hydrogenation of 2,5-HD at 90 °C, while Ru/HAP showed excellent performance on the conversion of 2,5-HD into N-substituted tetrahydropyrroles at 30 °C via direct reductive amination. Systematic study revealed that the property of support materials influenced the activity of Ru/MMT and Ru/HAP for the different routes, affording different reaction pathways for conversion of 2,5-HD.
Direct utilization of the abundant hydrogen and oxygen in water for organic reactions is very attractive and challenging in chemistry. Herein, we report the first work on the utilization of the ...hydrogen in water for the hydrogenation of various organic compounds to form valuable chemicals and the oxygen for the oxidation of glucose, simultaneously by photocatalysis. It was discovered that various unsaturated compounds could be efficiently hydrogenated with high conversion and selectivity by the hydrogen from water splitting and glucose reforming over Pd/TiO
under UV irradiation (350 nm). At the same time, glucose was oxidated by the hydroxyl radicals from water splitting and the holes caused by UV irradiation to form biomass-derived chemicals, such as arabinose, erythrose, formic acid, and hydroxyacetic acid. Thus, the hydrogen and oxygen were used ideally. This work presents a new and sustainable strategy for hydrogenation and biomass conversion by using the hydrogen and oxygen in water.
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