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In this paper, the adsorption of CO on FexCuy (x + y = 3) clusters was studied by BPW91 method, and all conceivable geometries and electronic states of carbonyl complexes were explored. The results show that bimetallic clusters tend to have higher stepwise CO adsorption energy than corresponding pure clusters, and the adsorption capacity of FeCu2 with CO is substantially larger than that of other carbonyl complexes. The CO bond length and CO stretching indicated that the CO bond is significantly weakened in Fe3(CO)6. In addition, the frontier molecular orbital theory was used to analyze the effect of the second element in the ligand reactions, which also confirmed that the reactions of CO with bimetallic clusters are easier than that of pure cluster systems. Finally, the energy gaps of HOMO and LUMO were used to explore the reactive activity of carbonyl complexes, and it was found that the Fe2Cu(CO)1 has lower energy gap than that of other carbonyl complexes. This suggests that it may be possible to tune bimetallic cluster to get higher activity carbonyl complexes in the reactions. [ABSTRACT FROM AUTHOR]

Motivated by the prominent catalytic performance and durability of nanoalloy catalysts, the Pd-based bimetallic nanoalloy catalysts were prepared using an aqueous reduction method. The Fe-Pd bimetallic nanoalloy catalyst (nano-Fe/Pd) demonstrated 98.4% yield and 99.7% selectivity for the unsaturated 1,4-dicarboxylic acid diesters. Moreover, the inductively coupled plasma (ICP) analysis shows that the Pd leaching of the catalyst can be effectively suppressed by alloying Fe atoms into the Pd crystal lattice for acetylene dicarbonylation. The detailed catalyst structure and morphology characterization demonstrate that introducing Fe into the Pd nanoparticles tunes the electronic–geometrical properties of the catalyst. Theoretical calculations indicate that the electrons of Fe transfer to Pd in the nano-Fe/Pd catalyst, enhancing activation of the C≡C bond in acetylene and weakening CO absorption capacity on catalyst surfaces. Alloying Fe into the Pd nanocatalyst effectively inhibits active metal leaching and improves catalyst activity and stability under high-pressure CO reactions. [ABSTRACT FROM AUTHOR]

The synthesis and X-ray structure of a novel glycoluril derivative are described. The crystal of the glycoluril derivative is obtained by slow evaporation in a refrigerator at about 5 °C. X-ray crystallographic analysis revealed that the compound crystallized in an unusual as conformation instead of the usual clip-shaped aa conformation. Structural analysis shows that the solvation effect, hydrogen bonding, and space-occupying effect influenced the crystallization conformation of the derivative. The X-ray crystallographic analysis in this work provides additional crystallographic evidence of the as conformation of the 3U glycoluril derivative and shows the effect of solvent water on the conformational behavior. [ABSTRACT FROM AUTHOR]

In order to improve the oil recovery, injection of exogenous bacteria into the oil reservoir is one of the most widely used microbial flooding methods. In this study, a screened strain of Bacillus subtilis (B. subtilis) was introduced to perform the microbial flooding. The biosurfactants produced by B. subtilis was one kind of cyclic lipopeptides, which could reduce the surface tension of the culture solution from 68 mN/m to 25 mN/m and also decrease the interfacial tension of water/oil from 25.6 to 4.6 mN/m. Emulsification tests indicated that the strain and the biosurfactants could degrade and emulsify the crude oil. In the oil displacement experiments, oil recovery was increased by 32.4% by injecting fermentation broth into the simulated formation. By respectively performing the emulsification and oil displacement tests, it was demonstrated that the biosurfactants and degradation of the microbes in the heavy components of the crude oil are the main factors to enhance the oil recovery. Besides, the optimal cultural temperature for strain of B. subtilis was set as 40°C. Nevertheless, the strain was inappropriate for the oil displacement under acidic conditions. In addition, the hydrophilic sands and an optimal culture solution volume of 0.7 pore volume (PV) would be in favor of the oil recovery. It was further confirmed that the efficiency of microbial flooding was much higher than that of the chemical oil displacement. [ABSTRACT FROM AUTHOR]

Functionalized carbon black (F-CB) nanoparticles were synthesized by covalently grafting the polyvinyl alcohol on carbon black (CB) surfaces and used as demulsifier to separate the oil from the emulsified oily wastewater. The bottle test showed that the residual oil content in the separated water was as low as ∼50 mg/L corresponding to a demulsification efficiency of about 99.90% at an optimal condition within a few minutes. It was believed that the surface wettability of the carbon black could be tuned by modifying with the PVA molecules, which enables the F-CB nanoparticles to be readily migrated to the oil/water interface and have the opportunity to interact with and/or displace the stabilizers of the emulsion. As a result, the demulsification process was accomplished with the coalescence of the oil droplets promoted by the F-CB nanoparticles. The interaction behavior between F-CB nanoparticles and asphaltenes was investigated by quantum chemical calculations. The results showed that the F-CB nanoparticles have strong interaction with the asphaltene molecules in form of π−π and θ−π forces. The findings in present study are significant for understanding the demulsification mechanism and also provide a novel demulsifier for the demulsification of emulsified oily wastewater. [ABSTRACT FROM AUTHOR]

• Co-, Ni-, and Ru-based catalysts show good primary amine selectivity. • The competitive adsorption of FAM and H 2 suppresses its excessive hydrogenation. • The adsorption energies of FAM on Co, Ni, and Ru surfaces are calculated. • The activation energy is not the key factor in determining the FAM hydrogenation. In addition to the main reaction, understanding the structure-activity relationship in the side reactions is another important goal for catalysis science. In this work, the catalytic activities and selectivities of various active metals were studied in the reductive amination of furfural (FAL). Compared with Co- and Ni-based catalysts, the excessive hydrogen of furfurylamine (FAM) was found over Ru-based catalysts at much higher reaction temperature (130 vs. 50 °C). Moreover, the evaluation of FAM hydrogenation undoubtedly substantiated the intimate relationship between H 2 reaction pressure and catalytic activity. Combining the theoretical and experimental results, it is clearly verified that the active metal determines the excessive hydrogen of FAM by affecting the competitive adsorption of FAM and H on the active sites. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbon nano-materials have been widely used in many fields due to their electron transport, mechanics, and gas adsorption properties. This paper introduces the structure and properties of carbon nano-materials the preparation of carbon nano-materials by chemical vapor deposition method (CVD)—which is one of the most common preparation methods—and reaction simulation. A major factor affecting the material structure is its preparation link. Different preparation methods or different conditions will have a great impact on the structure and properties of the material (mechanical properties, electrical properties, magnetism, etc.). The main influencing factors (precursor, substrate, and catalyst) of carbon nano-materials prepared by CVD are summarized. Through simulation, the reaction can be optimized and the growth mode of substances can be controlled. Currently, numerical simulations of the CVD process can be utilized in two ways: changing the CVD reactor structure and observing CVD chemical reactions. Therefore, the development and research status of computational fluid dynamics (CFD) for CVD are summarized, as is the potential of combining experimental studies and numerical simulations to achieve and optimize controllable carbon nano-materials growth. [ABSTRACT FROM AUTHOR]

[Objective] To study the influence of different processing methods to the quality of Cynanchum paniculatum, (Bge.) Kitaga. [Methods] To carry out comparing test of different drying and cleaning methods for Cynanchum paniculatum (Bge.) Kitaga. For comparing test of different drying methods, the content of paeonol, the active ingredient, was used as index to evaluate the effects of different processing technics on medicinal material quality. [Results] The drug quality can't be declined after the drug is washed quickly. Oven drying at low temperature is superior to traditional drying method. [Conclusions] The optimum processing method in producing area is that the drug is washed quickly, then drying by oven at the temperature gradient of 40↠50↠60 °C. [ABSTRACT FROM AUTHOR]