examines the effect of carbon on the oxidation state of iron during heat treatment and iron transfer in the subsequent hcl pretreatment step two catalyst sections were loaded in the reactor the first section contained 20 grams of 0 3 wt pt and 0 3 wt ir on al 2 o 3 extrudates coated with fe 2 o 3 to give 2 wt iron calculated based on metallic iron additionally 1 wt carbon with a surface area of about 800 m 2 g was also coated onto the extrudates the second section was loaded with 20 grams of catalyst extrudates discharged from a commercial reactor the catalyst extrudates contained 4 7 wt coke these extrudates were coated with fe 2 o 3 to a 2 wt loading calculated based on metallic iron the catalysts were heated up to 510 u00b0 c under helium and stayed at this temperature for about 30 minutes then without an intermediate hydrogen reduction step the catalyst extrudates were treated with 1 vol hcl for about 2 hours the amount of iron chemically bonded to the extrudates in the inlet and outlet sections were 1 32 and 1 76 wt respectively which is considerably higher than the results achieved in example 2 although no hydrogen reduction was used in this example it appears that hcl has reacted with the iron particles despite the fact that iron was introduced as fe 2 o 3 x ray diffraction analysis of the catalyst after.