الفهرس 
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Abstract
Producing gasoline of high octane number via hydroisomerization of light paraffins is an important industrial process. Unconventional sulphated zirconia (SZ) catalysts which have proved to acquire the highest activity were prepared by the sol-gel method. The sulfation was performed using H2SO4 acid, the weight ratio of Zr : S was 1:0.038. The calcination of the prepared catalysts at temperatures between 500 and 650℃ was studied and found to execute a strong influence. The crystallinity transforms to the denser form (monoclinic). However, the surface properties do not exhibit such effectiveness. Calcination at 500°C gives the best activities and stabilities, whereas at 650°C, calcination is deteriorative. The effect of addition of a traditionally active and stable noble metal has been achieved. Two groups of modified Sulfated Zirconia catalysts were prepared by incipient wetness. In the first group, monometallic catalysts containing Pt in different concentrations; 0.15 %, 0.3%, 0.45 and 0.6wt IV % have been prepared and examined as hydroisomerization catalysts. In the second group, bimetallic catalysts containing different Pt and Re combinations, in different ratios where the sum of the two metals is 0.6wt%have been prepared. All the prepared catalysts were characterized by X-Ray diffraction (XRD), Temperature programmed reduction analysis (TPR), Transmission electron microscopic analysis (TEM), Thermo gravimetric analysis (TGA), Infrared spectroscopy (IR) as well as surface properties using the Brunaure-Emmett-Teller (BET) method. The catalytic activity of the catalysts was examined via the isomerization reaction of n-pentane to iso-pentane. The catalytic activity was found to increase with increasing the Pt concentration in monometallic catalysts. The inclusion of Re ion together with Pt on SZ results in significant changes in the characters and activities of the catalysts. The 0.45wt%Pt/0.15wt%Re /SZ catalyst exhibited the highest activity and stability among the current catalysts.