The reaction network and mechanism of the synthesis of methylenedianiline (MDA) from the condensation product of aniline and formaldehyde (aminal) on microporous acidic materials has been elucidated. The first step of the reaction, the decomposition of the aminal to N-benzylanilines, is limited by film diffusion, and the second and significantly slower step, the acid catalyzed rearrangement of these intermediates to MDA, is controlled by microkinetics on mesoporous dealuminated Y-type zeolites. This second step of the reaction network is limited by pore diffusion on zeolite BEA as an example for non-mesoporous materials. Based on time-concentration profiles, we were able to determine the reaction orders of the initial decomposition of the aminal to one and two for the following rearrangement of para-aminobenylaniline to 4,4′-MDA. From the kinetic data we deduced an S_N2-type reaction mechanism and a complex reaction network, which is able to simulate the observed concentration profiles. The aniline to formaldehyde ratio in the starting mixture had a negligible influence on the final product distribution.