排序方式: 共有16条查询结果,搜索用时 15 毫秒
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Jordan Meyet Keith Searles Mark A. Newton Michael Wrle Alexander P. vanBavel Andrew D. Horton Jeroen A. vanBokhoven Christophe Copret 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(29):9946-9950
Monomeric CuII sites supported on alumina, prepared using surface organometallic chemistry, convert CH4 to CH3OH selectively. This reaction takes place by formation of CH3O surface species with the concomitant reduction of two monomeric CuII sites to CuI, according to mass balance analysis, infrared, solid‐state nuclear magnetic resonance, X‐ray absorption, and electron paramagnetic resonance spectroscopy studies. This material contains a significant fraction of Cu active sites (22 %) and displays a selectivity for CH3OH exceeding 83 %, based on the number of electrons involved in the transformation. These alumina‐supported CuII sites reveal that C?H bond activation, along with the formation of CH3O‐ surface species, can occur on pairs of proximal monomeric CuII sites in a short reaction time. 相似文献
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K. Nagy E. Kleven T. A. Fjeldly D. Fremstad 《Fresenius' Journal of Analytical Chemistry》1979,295(5):362-365
Summary A procedure for determination of sulphur in adsorbates based on combustion of samples in a high-frequency induction furnace, and subsequent registration by potentiometric titration in an alcoholic medium is described. Optimum conditions for the titration are discussed. A new type of indicator electrode with integrated impedance transformation electronics has been used. The technique was applied with good results to samples of secondary alumina (standard deviation 0.01%).
Potentiometrische Bestimmung von Schwefel in sekundärem Aluminiumoxid
Zusammenfassung Das beschriebene Verfahren zur Schwefelbestimmung in Adsorbaten beruht auf der Verbrennung der Probe in einem Hochfrequenz-Induktionsofen und nachfolgender potentiometrischen Titration in alkoholischem Medium. Die optimalen Titrationsbedingungen werden diskutiert. Es wurde eine neuartige Indicatorelektrode mit integrierter Impedanztransformation benutzt. Bei der Anwendung auf sekundäres Aluminiumoxid wurden gute Ergebnisse erzielt (Standardabweichung 0,01%).相似文献
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