N-HEXANE ISOMERIZATION OVER Pt, Pd CATALYSTS SUPPORTED ON MIXES of HY+γ-Al2O3
In this study, a decationized form of faujasite zeolite HY and mixes of this zeolite with alumina γAl2O3 of various ratios have been used as carriers for catalysts 0.35 wt.% Pt and 0.80 wt.% Pd. Physico-chemical characteristics of the obtained catalysts were determined by methods of BET, SEM, EDS, TEM, XRD, TPR, H2 pulse chemisorption (HPC), and TPD. Activity of the catalysts for n-hexane isomerization was tested at the temperature range 225-450oC and two values of pressure 0.1 and 0.7 MPa. In feed flows the molar ratio hydrogen: hydrocarbon was 5.92 with the concentration of n-hexane as 9.2 mol.%. It has been found that the value of optimal ratio γ -Al2O3: HY was 2.5:1. The effect of the mixed carriers is included in the reduction of acidity and metal crystallites, increase of metal dispersity and reducibility of catalyst and the improvement of catalyst stability. At 0.7 MPa the activity, selectivity, and stability of catalysts have been shown to be significantly higher than those obtained at 0.1 MPa.