The scope of this work is to present a rear case in which reactor performance predicted theoretically, avoiding the numerical integration within the particle, is compared with experimental findings. The influence of realistic catalytic activity distributions are also studied since minimum extra efforts are needed with the procedure presented in this contribution. The partial oxidation of methanol in a tubular catalytic reactor, studied by Windes et al. (1989), giving rise to formaldehyde and carbon monoxide as main reaction products, was used as example for the application of our procedure. Both, inter and intraparticle, diffusional limitations were taken into account. Experimental data and theoretical predictions along the reactor were compared in terms of outlet conversion and temperature profiles showing a fairly good agreement which gives support to the procedure developed in this contribution to predict. reactor performance. Furthermore, the effect of different realistic activity distribution function was simulated and its influence on the reactor performance is shown. The obtained results are discussed and some interesting conclusions are withdrawn.