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排序方式: 共有194条查询结果,搜索用时 312 毫秒
31.
Ivan Scodeller Samir Mansouri Dr. Didier Morvan Dr. Eric Muller Dr. Karine de Oliveira Vigier Dr. Raphael Wischert Dr. François Jérôme 《Angewandte Chemie (International ed. in English)》2018,57(33):10510-10514
We report the synthesis of biomass‐derived functionalized aromatic chemicals from furfural, a building block nowadays available in large scale from low‐cost biomass. The scientific strategy relies on a Diels–Alder/aromatization sequence. By controlling the rate of each step, it was possible to produce exclusively the meta aromatic isomer. In particular, through this route, we describe the synthesis of renewably sourced meta‐xylylenediamine (MXD). Transposition of this work to other furfural‐derived chemicals is also discussed and reveals that functionalized biomass‐derived aromatics (benzaldehyde, benzylamine, etc.) can be potentially produced, according to this route. 相似文献
32.
Inside Cover: Synthesis of Renewable meta‐Xylylenediamine from Biomass‐Derived Furfural (Angew. Chem. Int. Ed. 33/2018)
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33.
Partial oxidation of methane to formaldehyde and methanol was studied at atmospheric pressure in the temperature range of 700-750 °C using heteropolycompound catalysts (NH4)6HSiMo11FeO40, (NH4)4PMo11FeO39, and H4PMo11VO40, which were prepared and characterized by various analysis techniques such as infrared, visible UV, XRD and DTA. O2 or N2O was used as the oxidizing agent, and the principal products of the reaction were CH3OH, CH2O, CO, CO2, and water. The conversion and the selectivity of products depend strongly on the reaction temperature, the nature of oxidizing agent, and the composition of catalyst. 相似文献
34.
B. Mansouri N. Manamanni K. Guelton M. Djemai 《Nonlinear Analysis: Hybrid Systems》2008,2(4):1136-1143
This paper concerns the state feedback control for continuous-time, disturbed and uncertain linear switched systems with arbitrary switching rules. The main result of this work consists in getting a LMI (Linear Matrix Inequalities) condition guaranteeing a robust pole placement according to some desired specifications. Then, external disturbance attenuation with a fixed rate according to the H∞ criterion is ensured. This is obtained thanks to the existence of a common quadratic Lyapunov function for all sub-systems. Finally, an academic example illustrates the efficiency of the developed approach. 相似文献
35.
Mostafaie A Bidmeshkipour A Shirvani Z Mansouri K Chalabi M 《Applied biochemistry and biotechnology》2008,144(2):123-131
Actinidin is a cysteine protease abundant in Kiwifruit. This enzyme is known as a meat-tenderizing protease. In this project,
actinidin was purified from kiwifruit by salt precipitation and ion exchange chromatography. Collagenolytic effect of the
purified enzyme was tested in four different buffer systems. Thereafter, the enzyme was used for isolation and culture of
cells from three different tissues: endothelial cells from human umbilical vein, hepatocytes from rat liver, and thymic epithelial
cells from rat thymus. Our results revealed that actinidin can hydrolyze collagen types I and II at neutral and alkaline buffers.
Furthermore, actinidin compared with type II or IV collagenase isolated intact human umbilical vein endothelial cells, hepatocytes,
and thymic epithelial cells with viability more than 90%. These results address a novel and valuable collagenase, which can
be used efficiently for hydrolysis of collagen and isolation of different cell populations from various solid tissues. 相似文献
36.
Isothermal Cyclic Conversion of Methane into Methanol over Copper‐Exchanged Zeolite at Low Temperature
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Patrick Tomkins Ali Mansouri Dr. Selmi E. Bozbag Dr. Frank Krumeich Dr. Min Bum Park Dr. Evalyn Mae C. Alayon Dr. Marco Ranocchiari Prof. Dr. Jeroen A. van Bokhoven 《Angewandte Chemie (International ed. in English)》2016,55(18):5467-5471
Direct partial oxidation of methane into methanol is a cornerstone of catalysis. The stepped conversion of methane into methanol currently involves activation at high temperature and reaction with methane at decreased temperature, which limits applicability of the technique. The first implementation of copper‐containing zeolites in the production of methanol directly from methane is reported, using molecular oxygen under isothermal conditions at 200 °C. Copper‐exchanged zeolite is activated with oxygen, reacts with methane, and is subsequently extracted with steam in a repeated cyclic process. Methanol yield increases with methane pressure, enabling reactivity with less reactive oxidized copper species. It is possible to produce methanol over catalysts that were inactive in prior state of the art systems. Characterization of the activated catalyst at low temperature revealed that the active sites are small clusters of copper, and not necessarily di‐ or tricopper sites, indicating that catalysts can be designed with greater flexibility than formerly proposed. 相似文献
37.
Ce(IV) salophen encapsulated into dealuminated Y zeolite was prepared by the flexible ligand method. Incorporation of TiO2 into nanocages of dealuminated Y zeolite was performed by the impregnation method. The obtained photocatalyst was characterized by FT-IR, XRD, DRS, SEM, EDS and ICP techniques. The amount of Ce(salophen) in the zeolite supercages was 0.07 mg/g of encapsulated zeolite. This catalytic system was investigated in the photodegradation of 4-nitrophenol. In this work, the effect of dark conditions, and visible and UV illumination was investigated for the degradation of 4-nitrophenol. In addition, the effect of other parameters including catalyst loading, H2O2 and TiO2 was studied in the degradation of 4-nitrophenol. The obtained results reveal that the photocatalyst performance depends on catalyst loading, the presence of H2O2, and UV illumination. 相似文献
38.
Transient electrokinetic transport in a finite length microchannel: currents, capacitance, and an electrical analogy 总被引:1,自引:0,他引:1
Mansouri A Bhattacharjee S Kostiuk LW 《The journal of physical chemistry. B》2007,111(44):12834-12843
Numerical simulations with the fluid mechanics based on the unsteady Navier-Stokes equations and the Poisson-Nernst-Planck formulation of electrostatics and ion transport were used to explore the transient transport of charge through a finite length cylindrical microchannel that is driven by a pressure difference. The evolution of the transcapillary potential from a no-flow equilibrium to the steady-state-steady-flow streaming potential was analyzed by following the convection, migration, and net currents. Observations of the unsteady characteristics of the streaming current, electrical resistance, and capacitance led to an electrical analogy. This electrical analogy was made from a current source (to represent convection current), which was placed in parallel with a capacitor (to allow the accumulation of charge) and a resistor (to permit a migration current). A parametric study involving a range of geometries, fluid mechanics, electrostatics, and mass transfer states allowed predictive submodels for the current source, capacitor, and resistor to be developed based on a dimensional analysis. 相似文献
39.
Majid M. Moghaddam H.R. Ghazizadeh A. Mansouri 《Communications in Nonlinear Science & Numerical Simulation》2009,14(11):3833-3843
In this paper, the analytic solution of the buoyancy-driven flow over a horizontal impermeable flat plate embedded in a saturated porous medium is derived using the newly developed analytic method, namely the homotopy analysis method (HAM). The HAM results show great agreement comparing with numerical results. HAM contains an auxiliary parameter ? that provides a simple way of controlling and adjusting the convergence region. The resultant analytic solution is valid for all acceptable values of the temperature exponent parameter λ. 相似文献
40.
Solid-state structures of Mg, Sr, Ba, Na2, Na0.8K1.2, NaRb, and Na1.5Cs0.5 complexes of the disulfonated dye 7-hydroxy-8-(phenylazo)-1,3-naphthalenedisulfonic acid, Orange G, are presented. It is shown that the s-block metal salts of the Orange G dianion (Og) can be categorized into three structural classes related to those previously proposed for simple monosulfonated azo dyes. All of the structures feature alternate organic/inorganic layering, but whereas the Mg, Ca, and Li complexes are solvent-separated ion-pair species, the Sr and Ba complexes form simple discrete molecules based on metal-sulfonate bonding, and the heavy alkali metal complexes utilize a variety of M-O interactions to form 2- and 3-dimensional coordination networks. These structural differences are rationalized in terms of simple properties of the metals (charge, size, and electronegativity) and the steric demands of the arylsulfonate groups. The Ag2 complex of Orange G is also structurally characterized, and in contrast to the s-block salts, it is found to exhibit strong Ag pi bonds. In confirmation of the above, the crystal structures of [Mg(H2O)6][Og] . 3.33H2O, [Sr(Og)(H2O)7].H2O, [Ba(Og)(H2O)7]2 . 2H2O, [Na2(Og)(H2O)6.67], [Na2(Og)(H2O)2(HOEt)], [Na0.8K1.2(Og)(H2O)6] . 1.75H2O, [NaRb(Og)(H2O)6.5] . 2.375H2O, [Na1.5Cs0.5(Og)(H2O)6] . 0.5H2O, and [Ag2(Og)(H2O)4].H2O are presented. 相似文献