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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Catalysis letters 49 (1997), S. 199-205 
    ISSN: 1572-879X
    Keywords: decomposition ; hydrolysis ; heterogeneous catalysis ; dichlorodifluoromethane ; CFC-12 ; zirconia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The hydrolytic decomposition of dichlorodifluoromethane (CFC-12) on various modified zirconium oxide surfaces has been studied. The reaction was carried out under flow conditions at 500°C. Complete CFC-12 conversion and long-time stability of the catalysts were achieved accompanied by a limitation of the undesired CFC-13 formation. A maximum CFC-12 conversion was observed on catalysts of sulfated zirconia or zirconia obtained from temperature-controlled calcination of zirconium oxide hydrate. The reaction depends on the presence or in situ formation of Brønsted acid sites. FTIR-photoacoustic measurements were performed on pyridine complexes chemisorbed on the catalyst surface in order to analyze the changes in the catalyst's acidity. The effects of the temperature and water in the reaction gas on the catalyzed decomposition of CFC-12 are examined.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 1921-1924 
    ISSN: 0044-2313
    Keywords: Potassium hydrogen sulfate ; synthesis ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Potassium Hydrogensulfate, K(H3O)(HSO4)2  -  Synthesis and StructureSingle crystals of the new compound K(H3O)(SO4)2 are synthesized from the system potassium sulfate/sulfuric acid. The up to day not described compound crystallizes in the monoclinic space group P21/c with the unit cell parameters a = 7.203(1) b = 13.585(2) and c = 8.434(1) Å, β = 105.54(1)°, V = 795.1 Å3, Z = 4 and Dx = 2.107 g · cm-3.There are two crystallographically different tetrahedral SO3(OH) anions. The first kind S1 tetrahedra forms dimers, whereas the second kind S2 forms infinite chains bonded via hydrogen bridges. The S1 dimers are linked to the S2 chains via oxonium ions (hydrogen bonds).Potassium is coordinated by 8 oxygen atoms which belong to four different SO3(OH) tetrahedra. These potassium oxygen polyhedra are connected by common edges forming chains running parallel z.
    Notes: Im System Kaliumsulfat/Schwefelsäure ist ein neues, bisher nicht beschriebenes saures Sulfat der Zusammensetzung K(H3O)(HSO4)2 synthetisiert worden. Die Verbindung kristallisiert in der monoklinen Raumgruppe P21/c mit den Gitterkonstanten a = 7,203(1), b = 13,585(2) und c = 8,434(1) Å, β = 105,54(1)°, V = 795,1 Å3, Z = 4 und Dx = 2,107 g · cm-3.Es liegen zwei kristallographisch verschiedene SO3(OH)-Tetraeder vor. Die eine Tetraedersorte (S1) bildet Dimere aus, während die Tetraeder der Sorte S2 über Wasserstoffbrücken verbundene Ketten bilden. Die Dimeren der S1-Tetraeder sind mit den unendlichen Ketten der S2-Tetraeder über Oxoniumionen (Wasserstoffbrücken) verbrückt.Kalium ist von 8 Sauerstoffatomen, die vier verschiedenen SO3(OH) Tetraedern angehören, koordiniert. Die Kalium-Sauerstoff-Polyeder sind über gemeinsame Kanten miteinander verknüpft und bilden Ketten parallel der z-Achse.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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