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71.
Dr. Baoxiang Peng Dr. Chen Zhao Stanislav Kasakov Sebastian Foraita Prof. Dr. Johannes A. Lercher 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(15):4732-4741
The mechanism of the catalytic reduction of palmitic acid to n‐pentadecane at 260 °C in the presence of hydrogen over catalysts combining multiple functions has been explored. The reaction involves rate‐determining reduction of the carboxylic group of palmitic acid to give hexadecanal, which is catalyzed either solely by Ni or synergistically by Ni and the ZrO2 support. The latter route involves adsorption of the carboxylic acid group at an oxygen vacancy of ZrO2 and abstraction of the α‐H with elimination of O to produce the ketene, which is in turn hydrogenated to the aldehyde over Ni sites. The aldehyde is subsequently decarbonylated to n‐pentadecane on Ni. The rate of deoxygenation of palmitic acid is higher on Ni/ZrO2 than that on Ni/SiO2 or Ni/Al2O3, but is slower than that on H‐zeolite‐supported Ni. As the partial pressure of H2 is decreased, the overall deoxygenation rate decreases. In the absence of H2, ketonization catalyzed by ZrO2 is the dominant reaction. Pd/C favors direct decarboxylation (?CO2), while Pt/C and Raney Ni catalyze the direct decarbonylation pathway (?CO). The rate of deoxygenation of palmitic acid (in units of mmol moltotal metal?1 h?1) decreases in the sequence r(Pt black)≈r(Pd black)>r(Raney Ni) in the absence of H2. In situ IR spectroscopy unequivocally shows the presence of adsorbed ketene (C?C?O) on the surface of ZrO2 during the reaction with palmitic acid at 260 °C in the presence or absence of H2. 相似文献
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Dr. Katherine Koh Dr. Udishnu Sanyal Dr. Mal-Soon Lee Dr. Guanhua Cheng Dr. Miao Song Dr. Vassiliki-Alexandra Glezakou Dr. Yue Liu Dr. Dongsheng Li Dr. Roger Rousseau Dr. Oliver Y. Gutiérrez Dr. Abhijeet Karkamkar Dr. Miroslaw Derewinski Prof. Johannes A. Lercher 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1517-1521
Acid functionalization of a carbon support allows to enhance the electrocatalytic activity of Pd to hydrogenate benzaldehyde to benzyl alcohol proportional to the concentration of Brønsted-acid sites. In contrast, the hydrogenation rate is not affected when H2 is used as a reduction equivalent. The different responses to the catalyst properties are shown to be caused by differences in the hydrogenation mechanism between the electrochemical and the H2-induced hydrogenation pathways. The enhancement of electrocatalytic reduction is realized by the participation of support-generated hydronium ions in the proximity of the metal particles. 相似文献
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Inside Cover: Atomic‐Scale Determination of Active Facets on the MoVTeNb Oxide M1 Phase and Their Intrinsic Catalytic Activity for Ethane Oxidative Dehydrogenation (Angew. Chem. Int. Ed. 31/2016) 下载免费PDF全文
76.
The majority of research on annoyance as an important impact of noise, odor, and other stressors on man, has regarded the person as a passive receptor. It was however recognized that this person is an active participant trying to alter a troubled person-environment relationship or to sustain a desirable one. Coping has to be incorporated. This is of particular importance in changing exposure situations. For large populations a lot of insight can be gained by looking at average effects only. To investigate changes in annoyance and effects of coping, the individual or small group has to be studied. Then it becomes imperative to recognize the inherent vagueness in perception and human behavior. Fortunately, tools have been developed over the past decades that allow doing this in a mathematically precise way. These tools are sometimes referred to by the common label: soft-computing, hence the title of this paper. This work revealed different styles of coping both by blind clustering and by (fuzzy) logical aggregation of different actions reported in a survey. The relationship between annoyance and the intensity of coping it generates was quantified after it was recognized that the possibility for coping is created by the presence of the stressor rather than the actual fact of coping. It was further proven that refinement of this relationship is possible if a person can be identified as a coper. This personal factor can be extracted from a known reaction to one stressor and be used for predicting coping intensity and style in another situation. The effect of coping on a perceived change in annoyance is quantified by a set of fuzzy linguistic rules. This closes the loop that is responsible for at least some of the dynamics of the response to a stressor. This work thus provides all essential building blocks for designing models for annoyance in changing environments. 相似文献
77.
The use of time resolved FTIR spectroscopy for characterizing time dependent adsorbate concentrations has been demonstrated with the examples of adsorption/desorption of ammonia and of adsorption and reactions of propan-2-ol. Adsorption sites and adsorbate structures are discussed. 相似文献
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