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  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 71 (1998), S. 167-172 
    ISSN: 0268-2575
    Keywords: oxidative coupling of methane ; oxidative dehydrogenation of ethane ; strontium-promoted rare earth oxide catalysts ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sr-promoted rare earth (viz. La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er and Yb) oxide catalysts (Sr/rare earth ratio = 0·1) are compared for their performance in the oxidative coupling of methane (OCM) to C2 hydrocarbons and oxidative dehydrogenation of ethane (ODE) to ethylene at different temperatures (700 and 800°C) and CH4 (or C2H6)/O2 ratios (4-8), at low contact time (space velocity = 102000 cm3 g-1 h-1). For the OCM process, the Sr-La2O3 catalyst shows the best performance. The Sr-promoted Nd2O3, Sm2O3, Eu2O3 and Er2O3 catalysts also show good methane conversion and selectivity for C2 hydrocarbons but the Sr-CeO2 and Sr-Dy2O3 catalysts show very poor performance. However, for the ODE process, the best performance is shown by the Sr-Nd2O3 catalyst. The other catalysts also show good ethane conversion and selectivity for ethylene; their performance is comparable at higher temperatures (≥800°C), but at lower temperature (700°C) the Sr-CeO2 and Sr-Pr6O11 catalysts show poor selectivity. © 1998 SCI.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 72 (1998), S. 99-104 
    ISSN: 0268-2575
    Keywords: oxidative coupling of methane ; Li-MgO catalyst ; catalyst supports ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Deposition of Li-MgO catalyst on commonly used supports (containing SiO2, Al2O3, SiC, ZrO2, HfO2, etc.) causes a drastic reduction in the catalytic activity/selectivity for the oxidative methane coupling reaction and also in both the total and strong surface basicity. The decrease in the catalytic activity/selectivity and basicity is attributed to strong chemical interactions between the catalyst and support which occur during the high temperature (750°C) calcination/pretreatment of the catalyst. The chemical interactions result in catalytically less active binary and ternary metal oxides containing Li and/or Mg, thus deactivating the Li-MgO catalyst by consuming its active components. © 1998 SCI
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 72 (1998), S. 125-130 
    ISSN: 0268-2575
    Keywords: oxidative coupling of methane ; Mg-promoted La2O3 ; Ca-promoted La2O3 ; Sr-promoted La2O3 ; Ba-promoted La2O3 ; surface acidity and basicity ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The catalytic activity and selectivity of La2O3 and alkaline earth (viz. Mg, Ca, Sr and Ba) promoted La2O3 (alkaline earth metal/La = 0·1) catalysts in the oxidative coupling of methane (OCM) to C2-hydrocarbons (at 800°C, CH4/O2 ratio = 4 or 8 and gas hourly space velocity = 102000 cm3 g-1 h-1) have been investigated. The acidity and basicity distributions on these catalysts are measured by the temperature programmed desorption (TPD) of NH3 and CO2 from 50°C to 950°C, respectively. Both the acidity and basicity of the La2O3 catalysts and their activity in the OCM are strongly influenced by the alkaline earth promoter and its concentration. Among the catalysts, Sr-promoted La2O3 (Sr/La = 0·1) is the most active and selective catalyst for the OCM process. This catalyst contains a larger number of strong basic sites and intermediate strength acid sites. © 1998 SCI
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 1545-1550 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Homogeneous thermal cracking of ethane, which is an endothermic and hence energy-intensive process, was carried out in the presence of limited O2 under different process conditions (at 600°-850°C; O2/ethane ratio of 0-0.2; H2O/ethane ratio of 0-3.3; and space velocity of 2,000-11,000 h-1). The influence of a sulfur additive in the feed and reactor material on the process performance was also investigated. Noncatalytic oxycarcking of ethane in the presence of limited O2, greatly enhances not only the total conversion of ethane but also the conversion of ethane by purely thermal cracking. This process also occurs at a much lower contact time than that required to achieve the same conversion for the thermal cracking process. Also, both the exothermic oxidative conversion and the endothermic thermal cracking of ethane occur simultaneously, which makes this process very energy-efficeint, with a drastic reduction in external energy requirement and coke formation. By manipulating the process conditions, particularly the temperature and O2/C2H6 ratio, the overall process can be made almost thermoneutral, mildly exothermic, or mildly endothermic.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0044-8249
    Keywords: Cracken ; Dehydrierung ; Ethan ; Ethylen ; Heterogene Katalyse ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 34 (1995), S. 665-666 
    ISSN: 0570-0833
    Keywords: cracking ; dehydrogenation ; ethane ; ethylene ; heterogenous catalysis ; oxidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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