South African Journal of Chemistry
On-line version ISSN 1996-840X
Print version ISSN 0379-4350
DASIREDDY, Venkata D.B.C.; FRIEDRICH, Holger B. and SINGH, Sooboo. A kinetic insight into the activation of n-octane with alkaline-earth metal hydroxyapatites. S.Afr.j.chem. (Online) [online]. 2015, vol.68, pp.195-200. ISSN 1996-840X. http://dx.doi.org/10.17159/0379-4350/2015/v68a26.
Alkaline-earth metal hydroxyapatites are prepared by the co-precipitation method and characterized using XRD, ICP NH3-TPD, SEM-EDX, TEM and N2 physisorption analysis. The metal present in the hydroxyapatite influences the acidity of the catalyst. Oxidative dehydrogenation reactions carried out in a continuous flow fixed bed reactor showed that the selectivity towards desired products was dependent on the alkaline-earth metal in the hydroxyapatite. All hydroxyapatite catalysts showed high selectivity towards carbon oxides, followed by cracked products, octenes and aromatics. The highest selectivity and turnover numbers towards C8 products and a high specific rate was shown by Sr-HAp. The activation of Η-octane over these catalysts followed the Eley-Rideal mechanism.
Keywords : Keywords Hydroxyapatite; acidity; chemisorption; Η-octane; octenes; aromatics; oxidative dehydrogenation.