1. Ionic reaction mechanism. From the broad concept of acid and alkali to understand the role of a catalyst, the catalyst to most acids, alkalis, salts, such as aluminium oxide, silicic acid, aluminum and so on. Most of non-transition metal compounds, catalytic cracking, isomerization, alkylation, hydration and dehydration reaction function.
2. free radical reaction mechanism. Between reactants and catalyst activation of the latter due to oxidative-reductive effect in the reaction catalyst the valences of the elements involved in the process, the catalyst material, mostly of metal, metal oxide, Metal Sulfides, such as nickel, Platinum, vanadium, chromium oxide, molybdenum sulphide and oxide. Most of them are transition elements and their compounds, catalytic hydrogenation and dehydrogenation, oxidation of the reaction function.
3. the mechanism of Complexation reactions. Catalysts and reaction coordination and activation of the latter, by using the catalyst catalyst. Additional channel for the choice of catalyst catalyst is known to use a similar function, such as a known nickel hydrogenation catalysts for ethylene, you can try for propylene hydrogenation catalyst.