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51.
Konrad Eichhorn Colombo Vladislav V. Kharton Alexandre P. Viskup Andrei V. Kovalevsky Aliaksandr L. Shaula Olav Bolland 《Journal of Solid State Electrochemistry》2011,15(2):329-347
A gas turbine power plant for CO2 capture, based on oxygen-permeable membranes with mixed ionic-electronic conductivity, was analysed with respect to long-term
stability by means of numerical simulation. Due to the attractive transport and physicochemical properties of mixed-conducting
La2NiO4+δ, this nickelate was selected as a prototype membrane material for this application. Experiments showed very slow degradation
of La2NiO4+δ membranes at oxygen chemical potentials close to atmospheric conditions, which are associated with kinetic demixing and other
microstructure-related factors. Interaction with CO2 in the intermediate temperature range also leads to lower oxygen permeation, whilst increasing oxygen pressure may cause
partial phase decomposition and microstructural changes, thus again limiting the range of possible operation conditions. The
relevant operational constraints were included in a detailed membrane-based gas turbine power plant model. The membrane performance
degradation with time was approximated by a linear function with average rate of 3.3% per 1,000 operation hours. Furthermore,
performance deterioration of the gas turbine compressor and turbine were also considered. Simulations revealed that the power
plant is substantially affected by degradation of the ceramic membranes and turbomachinery components. The already rather
small operating window was further narrowed when compared with a conventional gas turbine power plant. Two different designs
of the membrane-based power plant were analysed: (1) with and (2) without additional combustors (afterburners) between the
membrane reactor and the gas turbine. Afterburners increase thermal efficiency as well as power output, but also lead to non-negligible
CO2 emissions. In order to have a frame of comparison, results for a conventional gas turbine power plant with degradation of
turbomachinery components are also presented. Simulations representing changes in ambient temperature and fuel composition
as well as failure incidents were executed to analyse the susceptibility of the gas turbine power plant to external and internal
changes. 相似文献
52.
Ying Su Christos S. Karamitros Julian Nomme Theresa McSorley Manfred Konrad Arnon Lavie 《Chemistry & biology》2013,20(4):533-540
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53.
Dr. Christian Kulp Konrad Gillmeister Prof. Dr. Wolf Widdra Prof. Michael Bron 《Chemphyschem》2013,14(6):1205-1210
The synthesis of Cu(core)Pt(shell) model catalysts by the direct electrochemical deposition of Pt on Cu particles is presented. Cu particles with an average diameter of 200 nm have been deposited on glassy‐carbon electrodes by double pulse electrodeposition from a copper sulfate solution. Subsequent deposition from a platinum nitrate solution under potential control allows for a high selectivity of the Pt deposition towards Cu. Using a combination of cyclic voltammetry, XPS and sputtering, the structure of the generated particles has been analyzed and their core–shell configuration proven. It is shown that the electrocatalytic activity for the oxygen reduction is similar to that of other PtCu catalyst systems. The synthesized structures could allow for the analysis of structure–activity relations of core–shell catalysts on the way to the simple and controlled synthesis of supported Cu(core)Pt(shell) nanoparticles as oxygen reduction catalysts. 相似文献
54.
Konrad Hindelang Alexander Kronast Dr. Sergei I. Vagin Prof. Bernhard Rieger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(25):8244-8252
For the first time, the adaptability of the C?C double bond as a versatile precursor for the postsynthetic modification (PSM) of microporous materials was extensively investigated and evaluated. Therefore, an olefin‐tagged 4,4′‐bipyridine linker was synthesized and successfully introduced as pillar linker within a 9,10‐triptycenedicarboxylate (TDC) zinc paddle‐wheel metal–organic framework (MOF) through microwave‐assisted synthesis. Different reactions, predominately used in organic chemistry, were tested, leading to the development of new postsynthetic reactions for the functionalization of solid materials. The postsynthetic oxidation of the olefin side groups applying osmium tetroxide (OsO4) as a catalyst led to the formation of a microporous material with free vicinal diol functionalities. The epoxidation with dimethyldioxirane (DMDO) enabled the synthesis of epoxy‐functionalized MOFs. In addition to that, reaction procedures for a postsynthetic hydroboration with borane dimethyl sulfide as well as a photoinduced thiol–ene click reaction with ethyl mercaptan were developed. For all of these PSMs, yields of more than 90 % were obtained, entirely maintaining the crystallinity of the MOFs. Since the direct introduction of the corresponding groups by means of pre‐synthetic approaches is hardly possible, these new PSMs are useful tools for the functionalization of porous solids towards applications such as selective adsorption, separation, and catalysis. 相似文献
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58.
Thomas Auth Dr. Christopher J. Stein Prof. Richard A. J. O'Hair Prof. Konrad Koszinowski 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(7):e202103130
High-valent tetraalkylcuprates(iii ) and -argentates(iii ) are key intermediates of copper- and silver-mediated C−C coupling reactions. Here, we investigate the previously reported contrasting reactivity of [RMiii Me3]− complexes (M=Cu, Ag and R=allyl) with energy-dependent collision-induced dissociation experiments, advanced quantum-chemical calculations and kinetic computations. The gas-phase fragmentation experiments confirmed the preferred formation of the [RCuMe]− anion upon collisional activation of the cuprate(iii ) species, consistent with a homo-coupling reaction, whereas the silver analogue primarily yielded [AgMe2]−, consistent with a cross-coupling reaction. For both complexes, density functional theory calculations identified one mechanism for homo coupling and four different ones for cross coupling. Of these pathways, an unprecedented concerted outer-sphere cross coupling is of particular interest, because it can explain the formation of [AgMe2]− from the argentate(iii ) species. Remarkably, the different C−C coupling propensities of the two [RMiii Me3]− complexes become only apparent when properly accounting for the multi-configurational character of the wave function for the key transition state of [RAgMe3]−. Backed by the obtained detailed mechanistic insight for the gas-phase reactions, we propose that the previously observed cross-coupling reaction of the silver complex in solution proceeds via the outer-sphere mechanism. 相似文献
59.
Rolle Rahikainen Pramila Rijal Tiong Kit Tan Hung‐Jen Wu Anne‐Marie C. Andersson Jordan R. Barrett Thomas A. Bowden Simon J. Draper Alain R. Townsend Mark Howarth 《Angewandte Chemie (International ed. in English)》2021,60(1):321-330
Matching of symmetry at interfaces is a fundamental obstacle in molecular assembly. Virus‐like particles (VLPs) are important vaccine platforms against pathogenic threats, including Covid‐19. However, symmetry mismatch can prohibit vaccine nanoassembly. We established an approach for coupling VLPs to diverse antigen symmetries. SpyCatcher003 enabled efficient VLP conjugation and extreme thermal resilience. Many people had pre‐existing antibodies to SpyTag:SpyCatcher but less to the 003 variants. We coupled the computer‐designed VLP not only to monomers (SARS‐CoV‐2) but also to cyclic dimers (Newcastle disease, Lyme disease), trimers (influenza hemagglutinins), and tetramers (influenza neuraminidases). Even an antigen with dihedral symmetry could be displayed. For the global challenge of influenza, SpyTag‐mediated display of trimer and tetramer antigens strongly induced neutralizing antibodies. SpyCatcher003 conjugation enables nanodisplay of diverse symmetries towards generation of potent vaccines. 相似文献
60.
Organozinc Pivalate Reagents: Segregation,Solubility, Stabilization,and Structural Insights
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Dr. Alberto Hernán‐Gómez Emma Herd Prof. Eva Hevia Dr. Alan R. Kennedy Prof. Dr. Paul Knochel Prof. Dr. Konrad Koszinowski Sophia M. Manolikakes Prof. Robert E. Mulvey Christoph Schnegelsberg 《Angewandte Chemie (International ed. in English)》2014,53(10):2706-2710
The pivalates RZnOPiv?Mg(OPiv)X?n LiCl (OPiv=pivalate; R=aryl; X=Cl, Br, I) stand out amongst salt‐supported organometallic reagents, because apart from their effectiveness in Negishi cross‐coupling reactions, they show more resistance to attack by moist air than conventional organometallic compounds. Herein a combination of synthesis, coupling applications, X‐ray crystallographic studies, NMR (including DOSY) studies, and ESI mass spectrometric studies provide details of these pivalate reagents in their own right. A p‐tolyl case system shows that in [D8]THF solution these reagents exist as separated Me(p‐C6H4)ZnCl and Mg(OPiv)2 species. Air exposure tests and X‐ray crystallographic studies indicate that Mg(OPiv)2 enhances the air stability of aryl zinc species by sequestering H2O contaminants. Coupling reactions of Me(p‐C6H4)ZnX (where X=different salts) with 4‐bromoanisole highlight the importance of the presence of Mg(OPiv)2. Insight into the role of LiCl in these multicomponent mixtures is provided by the molecular structure of [(THF)2Li2(Cl)2(OPiv)2Zn]. 相似文献