排序方式: 共有22条查询结果,搜索用时 218 毫秒
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Anina Wöhl Dr. Wolfgang Müller Dr. Stephan Peitz Normen Peulecke Dr. Bhaskar R. Aluri Dr. Bernd H. Müller Dr. Detlef Heller Dr. Uwe Rosenthal Prof. Dr. Mohammed H. Al‐Hazmi Dr. Fuad M. Mosa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(26):7833-7842
In this paper we report the results of an extensive experimental kinetic study carried out on the novel ethylene trimerization catalyst system, comprising the chromium source [CrCl3(thf)3] (thf=tetrahydrofuran), a Ph2P‐N(iPr)‐P(Ph)‐N(iPr)H (PNPNH) ligand (Ph=phenyl, iPr=isopropyl), and triethylaluminum (AlEt3) as activator. It could be shown that the initial activity shows a first‐order dependency on the ethylene concentration. Also, a first‐order dependency was found for the catalyst concentration. The initial activity follows a typical Arrhenius behavior with an experimentally determined activation energy of 52.6 kJ mol?1. At elevated temperatures (ca. 80 °C), a significant deactivation was observed, which can be tentatively traced back to a ligand rearrangement in the presence of AlEt3. After a fast initial phase, a pronounced ‘kink’ in the ethylene‐uptake curve is observed, followed by a slow, almost linear, further increase of the total ethylene consumption. The catalyst composition, in particular the ligand/chromium and the cocatalyst/chromium molar ratio, has a strong impact on the catalytic performance of the trimerization of ethylene. 相似文献
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Compared to internal combustion engines, proton-exchange membrane fuel cells (PEMFC) operate with zero emissions of environmental
pollutants being this an adequate choice for transportation field. The increase of the operation temperature of PEMFC above
130°C is a great concern for the commercial application of the cells in electric vehicles. Hybrid organic-inorganic nanostructured
membranes can combine the main properties to meet this objective: high proton conductivity along with thermal and chemical
stability. The possibilities of synthesis of these hybrid structures grow exponentially with the combination of sol-gel chemistry
and monomers. Three different approaches have been followed for obtaining hybrid membranes that present the properties needed
for application in high temperature PEMFC: development of methacrylate and epoxy structures, and optimization of the inorganic
component incorporating phosphorus. Proton conductivity has been endowed on the base of three strategies: a high concentration
of hydroxyl groups from inorganic component,
groups through sulfonation of phenyl rings, and incorporation of tungstophosphoric acid, H3[P(W3O10)4]. 相似文献
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It is shown that thiol-containing antioxidants and stabilisers can be chemically reacted with ABS in high yields and in substantial concentrations under conditions of high temperature and high shear during processing. The resulting antioxidant concentrates are shown to be very effective thermal and photo-oxidative stabilisers for ABS when used as masterbatch additives for unstabilised ABS. Synergistic combinations of a bound antioxidant (BHBM (I(a))) and a bound uv stabiliser (EBHPT (II)) confer a high level of uv stability on ABS when incorporated into ABS. All the antioxidants show a high resistance to removal from the polymer by solvent extraction. The effect of the mechano-chemical process on the efficiency of adduct formation and on the effectiveness of the stabilisers so formed is discussed. 相似文献
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Jadra Mosa Adrián Carretero-Genevrier David Grosso Christel Laberty-Robert Clement Sanchez 《Journal of Solid State Electrochemistry》2013,17(4):1099-1107
Homogeneous, circular Pt||ZrO2 nanoelectrodes have been synthesized through the sol–gel chemistry and the dip-coating process. These nanoelectrode arrays have been evaluated as a platform for electropolymerization of phenol, as model. We have shown that the microstructure of the polymer depends on the confined environment of the electrode and on the position of the –OH group of the monomer. Additionally, these nanoelectrodes have been tested as an electrochemical sensor for dihydroxybenzene isomers in aqueous medium. These Pt||ZrO 2 nanoelectrodes exhibit a detection limit of 2?×?10?7?M for resorcinol and 1?×?10?6?M for catechol. 相似文献
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Alaa Z. Omar Najla A. Alshaye Tawfik M. Mosa Samir K. El-Sadany Ezzat A. Hamed Mohamed A. El-Atawy 《Molecules (Basel, Switzerland)》2022,27(12)
A new N,N′-disubstituted piperazine conjugated with 1,3,4-thiadiazole and 1,2,4-triazole was prepared and the chemical structures were identified by IR, NMR and elemental analysis. All the prepared compounds were tested for their antimicrobial activity. The antimicrobial results indicated that the tested compounds showed significant antibacterial activity against gram-negative strains, especially E. coli, relative to gram-positive bacteria. Docking analysis was performed to support the biological results; binding modes with the active site of enoyl reductase amino acids from E. coli showed very good scores, ranging from −6.1090 to −9.6184 kcal/mol. Correlation analysis was performed for the inhibition zone (nm) and the docking score. 相似文献
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Synthesis,Characterization, Molecular Structure,and Electrochemistry of a New Ferrocenoyl Derivative
Ana I. Matesanz Isabel Cuadrado Jadra Mosa Irene García Pilar Souza 《无机化学与普通化学杂志》2005,631(11):1979-1981
A new organometallic compound containing a heterocyclic amine linked to the ferrocenoyl moiety was synthesized and characterized by elemental analysis (C, H, N), mass spectrometry, IR and 1HNMR spectroscopy. Its crystal and molecular structure was determined by X‐ray diffraction methods. This compound crystallizes in the monoclinic P21 space group, a = 5.80260(10), b = 9.24160(10), c = 12.3510(2) Å, β = 92.8200(10)° and Z = 2. An interesting feature of the crystal structure is the presence of an intermolecular non‐classical hydrogen bonding interaction between a cyclopentadienyl hydrogen atom and a carbonyl oxygen group. The electrochemical behaviour of this compound is characterized by the reversible one‐electron oxidation of the ferrocene moiety. 相似文献
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An improved total synthesis of spermatinamine, an inhibitor of the anticancer target, isoprenylcysteine carboxy methyltransferase (Icmt) was accomplished from the commercially available 3,4-dibromo-4-hydroxybenzaldehyde via a high yielding reaction sequence in an overall yield of 31%. 相似文献