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  • 1975-1979  (14)
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Materialart
Erscheinungszeitraum
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    IR-spectroscopic study of the effect of the CoO concentration of CoO-MgO solid solutions on the activation energy for oxidation of the surface forms of CO (1979)
    Springer
    Russian chemical bulletin 28 (1979), S. 883-886 
    Details
    ISSN: 1573-9171
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Conclusions 1. Kinetic parameters for the oxidation of two surfaces forms of CO on CoO-MgO solid solutions have been determined by IR spectroscopy. The values obtained indicate that these forms differ in their reactivities with respect to oxygen. 2. Comparison of the effect of concentration changes on the activation energy for oxidation on cluster centers and on Weiss centers suggests that the exceptional properties of the cluster centers are due to weakening of the Co-to-surface bonding resulting from indirect exchange.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00963289
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  • 2
    Digitale Medien
    Digitale Medien
    IR-spectroscopic study of the variation of the activation energy for the oxidation of the surface forms of CO with the concentration of NiO in NiO-MgO solid solutions (1979)
    Springer
    Russian chemical bulletin 28 (1979), S. 2246-2249 
    Details
    ISSN: 1573-9171
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Conclusions 1. The presence of clusters gives rise to a nonstatistical distribution of Ni2+ ions in MgO. 2. The energy of activation for the oxidation of CO adsorbed on clusters varies in parallel with the Weiss constant under alteration of the solid solution concentration. 3. Intensification of the indirect exchange interaction leads to an alteration of the orbital transfer of electron density to the CO molecule, and from the latter to the Ni2+ ion, thereby giving rise to deforming forces and alteration of the force constant for the Ni2+-C bond. The effect of these two factors is to reduce the activation energy by intensifying the indirect exchange interaction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00951692
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  • 3
    Digitale Medien
    Digitale Medien
    Flowing cell-reactor for recording infrared spectra of adsorbed molecules during catalysis (1976)
    Springer
    Journal of applied spectroscopy 24 (1976), S. 127-128 
    Details
    ISSN: 1573-8647
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01100743
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  • 4
    Digitale Medien
    Digitale Medien
    Quantum-chemical investigation of the interaction of propene and oxygen with solid CoO−MgO surfaces (1976)
    Springer
    Reaction kinetics and catalysis letters 4 (1976), S. 269-274 
    Details
    ISSN: 1588-2837
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Abstract С помощью квантово-химического метода изучались взаимодействие пропилена и кислорсда с ионами Co2+, Co3+ и Mg2+ на поверхности решетки MgO, а также адсорбция заряженной формы O 2 − и п-аллиьного радикала. Показано, что адсорбция пропилена должна происходить более прочно на ионах Co3+, чем на ионах Co2+ и Mg2+. В противо-положность пропилену кислород адсорбируется более прогно на ионах Co2+ с последующим электронным переносом на молекулу кислорода. Полученные результаты сопоставлены с экспериментальными данными.
    Notizen: Abstract The interaction of propene and oxygen with Co2+, Co3+ and Mg2+ ions on the MgO lattice surface, as well as the adsorption of charged forms of O 2 − and π-allyl radical have been studied by a quantum-chemical method. Propene adsorption has been found to be stronger on Co3+ than on Co2+ and Mg2+ ions. Unlike propene, oxygen is adsorbed more strongly on Co2+ ions with subsequent electron transfer to an oxygen molecule. The data obtained are compared with experimental results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02062008
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  • 5
    Digitale Medien
    Digitale Medien
    Investigation of supported WO3 catalysts for propene metathesis by diffuse reflectance spectroscopy (1978)
    Springer
    Reaction kinetics and catalysis letters 8 (1978), S. 257-261 
    Details
    ISSN: 1588-2837
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Abstract Измерены спектры диффузного отражения катализаторов диспропорционирования пропилена WO3/SiO2 и WO3/γ-Al2O3 для различных стадий обработки зтих образцов, в частности, для случая обработки WO3/SiO2 парами HCl. Покзано, что в случае WO3/γ-Al2O3 температуры начала реакции и восстановления окиси вольфрама совпадают.
    Notizen: Abstract Diffuse reflectance spectra have been recorded for WO3/SiO2 and WO3/γ-Al2O3 catalysts after various steps of treatment of these samples, in particular, after treatment of WO3/SiO2 by HCl. It is shown that for WO3/γ-Al2O3 the temperatures of the onset of reaction and WO3 reduction coincide.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02061314
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  • 6
    Digitale Medien
    Digitale Medien
    Diffuse reflectance spectroscopic studies of supported molybdenum oxide catalysts for propene metathesis (1978)
    Springer
    Reaction kinetics and catalysis letters 8 (1978), S. 347-352 
    Details
    ISSN: 1588-2837
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Abstract Измерены спектры диффузного отражения окиси молибдена, нанесенной на γ-Al2O3 и SiO2 в количестве 10% вес. для различных стадий обработки этих систем. γ-Al2O3 была предварительно обработана 0,05% и 1,0% KOH. Сравнение полученных в настоящей работе спектральных данных и каталитических свойств этих систем позволяет сделать заключение об оптимальном окислительном состоянии ионов молибдена в поверхностных кластерах (∼ Mo5+), необходимом для получения нанесённых окисномолибденовых катализаторов диспропорционирования пропилена с высокой каталитической активностью и селективностью.
    Notizen: Abstract Diffuse reflectance spectra of 10 wt.% MoO3 supported on γ-Al2O3 and SiO2 have been measured after various steps of treatment. γ-Al2O3 was pretreated by 0.05 and 1.0 wt.% KOH. The comparison of spectral data and catalytic properties allows to predict the optimal oxidation state of molybdenum ions in surface clusters (approximately Mo5+), necessary to obtain supported MoO3 catalysts for propene metathesis with high activity and selectivity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02068177
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  • 7
    Digitale Medien
    Digitale Medien
    Thermodesorption studies on the interaction of propylene with solid CoO−MgO solutions (1975)
    Springer
    Reaction kinetics and catalysis letters 2 (1975), S. 211-215 
    Details
    ISSN: 1588-2837
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Abstract Проведены термодесорбционные исследования взаимодействия пропилена и кислорода на твердых растворах CoO−MgO. Получены значения энергии активации десорбции, Ed, для 12% CoO−MgO 1,5% CoO−MgO и MgO рав ные 10,5, 6,5 и 8,8 ккал/моль, соответственно. Показано, что предварительнчя адсорбция кислоропа или совместная алсорбция кислорода на исследованных твердых растворах приводит к необратимой адсорбции пропилена.
    Notizen: Abstract Thermodesorption studies on the interaction of propylene and oxygen over solid CoO−MgO solutions have been carried out. The activation energy of desorption, Ed, for 12% CoO−MgO, 1, 5% CoO−MgO and MgO samples was found to be 10.5, 6.5 and 8.8 kcal/mol, respectively. Pre-adsorption of oxygen or simultaneous adsorption of propylene and oxygen were shown to lead to irreversible adsorption of propylene on the solid solutions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02068193
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  • 8
    Digitale Medien
    Digitale Medien
    ESR study of the interaction of oxygen and propene with solid CoO−MgO solutions under pulse conditions (1976)
    Springer
    Reaction kinetics and catalysis letters 4 (1976), S. 275-279 
    Details
    ISSN: 1588-2837
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Abstract Методом ЭПР показано, что на поверхности 1% CoO−MgO после подачи на образец импульсов кислорода при комнатной температуре образуются ион-радикалы O 2 − с gI=2.0085 и gII=2.087. Нагревание образца в резонаторе спектрометра до 150 °C приводит к полному исчезновению в ЭПР-спектрах сигнала O 2 − . Получена зависимость изменения интенсивности сигнала O 2 − во времени как результат взаимодействия адсовбированных пропилена и кислорода на поверхности образца.
    Notizen: Abstract An ESR study has shown that under the action of oxygen pulses, radical ions O 2 − with gI=2.0085 and gII=2.087 are generated at room temperature on the surface of 1% CoO−MgO. Heating of the sample to 150 °C in the spectrometer results in complete disappearance of the O 2 − signal from the ESR spectra. The variation of the O 2 − signal intensity with time due to the interaction between propene and oxygen adsorbed on the sample surface, has been measured.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02062009
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  • 9
    Digitale Medien
    Digitale Medien
    IR Spectroscopy study of the interaction of methylpyrazine and 4-methylpyrimidine with vanadium and molybdenum oxides supported on magnesium oxide (1977)
    Springer
    Russian chemical bulletin 26 (1977), S. 2287-2292 
    Details
    ISSN: 1573-9171
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Conclusions 1. The introduction of vanadium and molybdenum oxides into MgO gives rise to the formation of acid centers which bond with adsorbed methylpyrazine and 4-methylpyrimidine through the ring nitrogen atom. 2. Increasing the temperature changes the state of these active centers and thereby increases the strength of coordinational bonding of the methylpyrazine and 4-methylpyrimidine with the surface of the vanadium and molybdenum oxides on MgO. Similar effects are not observed in the interaction of these diazines with the γ-Al2O3 surface. 3. The interaction of oxygen with methylpyrazine and 4-methylpyrimidine adsorbed on vanadium and molybdenum oxides supported by MgO gives rise to the formation of surface heterocyclic carbonyl compounds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00958712
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  • 10
    Digitale Medien
    Digitale Medien
    Magnetic and chemisorptional properties of dilute, highly dispersed CoO-MgO solid solutions (1977)
    Springer
    Russian chemical bulletin 26 (1977), S. 2474-2478 
    Details
    ISSN: 1573-9171
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Conclusions 1. The CO adsorbed on CoO-MgO solid solutions with high specific surface areas is bound to three different types of surface centers. The first type is a pair of Co2+ ions, one in octahedral coordination and one in square pyramidal coordination, each weakly interacting with neighboring ions. The second type of center is an individual Co2+ ion in square pyramidal coordination and strongly interacting with neighboring Co2+ ions in the same coordination. The third type of center is a variant of the second, one ion Co2+ ion in square pyramidal coordination interacting with neighboring Co2+ ions in octahedral coordination. 2. The CO molecule bonds more firmly to centers of the first type than to centers of either of the other types.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00924547
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