In the present paper a comparative consideration is given for the physico-chemical phenomena involved in homogeneously and heterogeneously catalyzed reactive distillation processes (RDP). The processes are classified qualitatively by dimensionless parameter groups derived from the balances for vapor, liquid and solid phases according to the principles of irreversible thermodynamics. The groups are applied to analyze industrial processes and experimental data for esterification, etherification and alkylation regarding different catalysts, operating conditions and configurations of plants. The mathematical models published until today and the experimental results are contrasted taking the parameter groups as a basis. This gives a discrimination of the models and some recommendations for their applicability.