Physicochemical methods are frequently used for characterizing the acid-base catalysts which are involved in many industrial processes, with the problem of large differences between their operating conditions and those of catalytic reactions. This drawback does not exist with model reactions, their use demanding essentially a thorough knowledge of their mechanism: intermediates, characteristics of the active sites: nature (acid, base, acid base), strength, density, environment and their effect on the reaction rate. The contribution of model reactions of hydrocarbons (alkanes, alkenes, methylbenzenes) and functional compounds (alcohols, 2-methylbut-3-yn-2-ol, acetone) in the characterization of various acid-base catalysts: oxides (SiO2-Al2O3, Al2O3, MgO, etc.) and zeolites, is critically evaluated.