Alcohols interact with both homogeneous and heterogeneous catalysts. Homogeneous catalysts are typically soluble in the same phase as the reactants, such as acids or bases in liquid-phase reactions. Heterogeneous catalysts, on the other hand, are in different phases, like solid catalysts in a liquid reaction mixture. Metals such as palladium, platinum, and rhodium are often employed as heterogeneous catalysts for alcohol reactions.