Hydroconversion of n-decane on Pt/HZSM-5 bifunctional catalysts: effect of the Si/Al ratio of the zeolite on selectivities

Hydroconversion of n-decane was investigated on a series of platinum loaded ZSM-5 samples with varied Si/Al ratio. It was observed that the catalytic activity of ZSM-5 zeolite catalysts decreased with increasing Si/Al ratios in samples. The isomer selectivity in the platinum catalysts increased with the Si/Al ratio, which can be explained by a better balance between acidic and hydrogenating sites (high nPt/nH(+) ratio = 0.3). On this catalyst, the olefinic intermediates formed on Pt come into contact with few acidic sites before encountering a Pt particle again on which they hydrogenate to be transformed into branched isomers. Among the various C(10) isomers, 2-MeC(9) was preferentially formed. On all catalysts, the content of linear products in the carbon number fractions is higher than branched products. This result is interpreted by type C hydrocracking of methylnonanes.