The paper evaluates, by modeling and simulation, 2-ethyl-hexenal hydrogenation process in catalytic trickle bed three-phase reactors. The mathematical model consists of balance equations for gas and liquid phases. Reaction rate equations, transport models and mass balances were coupled to generalized heterogeneous models which were solved with respect to time and space with algorithms suitable for partial differential equations. The importance of mass transfer resistance inside the catalyst pellets as well as the dynamics of the different phases being present in the reactor is revealed. The dynamic mathematical model presented can be used to analyze and understand the interaction of various processes that take place inside the hydrogenation reactor and also to make preliminary calculation of experimental parameters. Another important use of the mathematical model is to determine the optimal operation conditions and to design the control system. The model is implemented in Matlab and tested in simulations achieving successful results. (C) 2012 Elsevier Ltd. All rights reserved.