Hydrogenolysis of N-heptane over Nickel supported catalysts: influence of experimental conditions on selectivity

Abstract

The hydrogenolysis of n-heptane over 2%, 4%, 6% and 8% Ni / Al2 O3 was studied in a flow reactor using a pulse technique. The rate of. reaction in relation to the reactor temperature was observed and its dependency on the partial pressure of hydrogen and n-heptane was also determined. Catalysts at 6% and 8% nickel loading show appreciable catalytic activity as compared to the other two catalysts. Similarly, the effect of temperature on the reaction rate is very prominent on the high nickel loading catalysts with greater rate increase at more elevated temperature. The rate was also found to be greatly influenced by an increase in n-heptane partial pressure while higher partial pressure of hydrogen appears to impede the ease by which the reaction proceeds. Hydrogenolysis with nickel catalysts is observed to produce methane preferentially with ethane, propane, butane, pentane and hexane as minor products. A plausible mechanism is presented supporting a-scission cleavage of the n-heptane.