Within the porous catalyst particles

As a measure of the (de)hydrogenation function of a catalyst we determine a quantity proportional to the rate constant for the dehydrogenation of cyclohexane under standard conditions. This involves a catalytic test operation providing for (a) conversion levels far below thermodynamic equilibrium conversion, (b) negligible reactant concentration gradients in the catalyst bed, (c) negligible reactant concentration gradients within the (porous) catalyst particles. 

R is the overall resistance for a first order reaction with internal diffusion within the porous catalyst particles For kinetics different from first order, the relations for both R and R will be different and, as a rule, will still contain a concentration term For instance for n-th order kinetics Equation (24) is still valid in good approximation provided is defined according to ... 

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