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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/12321

Title: Activities of γ-Al2O3-supported metal oxide catalysts in propane oxidative dehydrogenation
Authors: Al-Zahrani, S.M.
Jibril, B.Y.
Abasaeed, A.E.
Keywords: Chromium oxide; Molybdenum oxide; Oxidative dehydrogenation; Propane; Propylene; TPR; XPS
Issue Date: 2003
Citation: Catalysis Letters : Volume 85, Issue 1-2, Pages 57-67
Abstract: The activities of metal oxide catalysts in propane oxidative dehydrogenation to propene have been studied. The catalysts are M/γ-Al2O3 (where M is an oxide of Cr, Mn, Zr, Ni, Ba, Y, Dy, Tb, Yb, Ce, Tm, Ho or Pr). Both transition metal oxides (TMO) and rare-earth metal oxides (REO) are found to catalyze the reaction at 350-450 °C, 1 atm and a feed rate of 75 cm3/min of a mixture of C 3H8, O2 and He in a molar ratio of 4:1:10. Among the catalysts, Cr-Al-O is found to exhibit the best performance. The selectivity to propene is 41.1% at 350 °C while it is 54.1% at 450 °C. Dy-Al-O has the highest C3H6 selectivity among the REO. At 450 °C, the other catalysts show C3H6 selectivity ranging from 16.2 to 37.7%. In general TMO show higher C3H 6 selectivity than REO, which, however, show higher C 2H4 selectivity. An attempt is made to correlate propane conversion and selectivity to C3H6 with metal-oxygen bond strength in the catalysts. For the TMO a linear correlation is found between the standard aqueous reduction potential of the metal cation of the respective catalyst and its selectivity to propane at 11% conversion. No such correlation has been found in the case of REO. Analyses of the product distributions suggest that for TMO propane activation the redox mechanism seems to prevail while the REO activate it by adsorbed oxygen.
URI: http://hdl.handle.net/123456789/12321
ISSN: 1011372X
Appears in Collections:College of Engineering

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