Hydrocracking of n‐heptane. Study of NiO—MoO₃ catalysts supported on a HY ultrastable zeolite

Abstract

The hydrocracking of n‐heptane in the temperature range of 573 to 623 K and at 2.45 × 106 Pa pressure has been employed as a test reaction for the study of Ni—Mo bifunctional catalysts supported on a HY ultrastable zeolite. Two groups of catalysts containing 8 and 12 wt% of MoO3 and different amounts of NiO have been studied. In both series a maximum in the activity has been obtained for catalysts with a Ni/Mo atomic ratio of 0.8‐1.0. The order of the impregnation of the oxides can have little influence on the activity. The most active catalyst has been obtained when the zeolite is exchanged with NH+4 ions until the Na+ level is less than 2% of the original and calcined at 823 K to obtain a HY ultrastable zeolite. Using this catalyst the rate controlling step could be the transformation of the carbonium ion on the acid sites.

Activity and selectivity of nickel-molybdenum/HY ultrastable zeolites for hydroisomerization and hydrocracking of alkanes

“…A direct relation is found however when considering only the samples with a Ni/(Ni + Mo) > 0.5 (Figure 9). These results would be in agreement with a previous work (Vázquez et al, 1986), which presented, on the basis of kinetic data, that for Ni/(Ni + Mo) < 0.44-0.5, the controlling step of the hydrocracking is the dehydrogenation of n-heptane on the metal, while for samples with Ni/(Ni 4• Mo) > 0.5 the reaction of carbonium ion on the acid centers is the controlling step.…”

Hydrocracking of n-heptane with a nickel monoxide-molybdenum trioxide/HY ultrastable zeolite as catalyst. The network of the reaction

“…The experiments were carried out in a continuous, tubular, plug flow, stainless steel reactor of 40 cm length and 2 cm internal diameter. The apparatus has been described in detail in a previous work (Vázquez et al, 1986).…”