Control of Selectivity through Kinetic Coupling between Heterogeneous Catalytic Cycles

Modifier Non-polar stearic acid Polar piperidine bicarbonate 

This example of kinetic coupling is particularly interesting because it deals with selectivity the effect on selectivity is not due to a change in kinetic parameters but to a change in thermodynamic parameters. 

The data represented by circles correspond to calculated partial pressures of n-pentene in equilibrium with n-pentane and H2 vs. the measured rate of isomerization of n-pentane on Pt/Al203. The slope of the straight line in the doubly logarithmic plot is one-half as observed separately. The experimental rate represented by a square is that of isomerization of n-pentene alone on the same alumina as used for the Pt/Al203 catalyst with the same acidity. The 

Schematic representation of two coupled catalytic cycles in the isomerization of n-pentane to i-pentane on a bifunctional catalyst consisting of platinum supported on acidic alumina 

Rate of isomerization versus partial pressure of pentene. The slope gives the observed reaction order a = 0.5 for the isomerization of pentene 

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