CATALYTIC REFORMING OF n-HEPTANE ON PLATINUM-TUNGSTEN SUPPORTED ON GAMMA-ALUMINA

Abstract

The mono-metallic and bi-metallic catalysts have been prepared by impregnating with solutions containing a compound of H₂PtCl₆,WO₃ and 1ml HCl (0.1 mol). It should be noted that the catalysts' activity and selectivity have been determined under these conditions : 450-500⁰C ,and 15-25atm by H₂. For converting n-heptane , the molar ratio H₂/C₇H₁₆ is 5 , and LHSV is 1.5ml/h. It has been proved that , under these experimental conditions , the conversion of n-heptane into branched aliphatic isomers is catalyzed by a bifunctional mechanism. The results indicate that in the presence of W , the catalysts have much higher selectivity and stability for isomerization reaction. At a given conversion , the bi-metallic catalysts produce much lower concentrations of cracked products. According to the tests , W modifies the support acidity resulting to the higher selectivity for isomerization and the lower one for cracking , and it also modifies the Pt properties