[en] In this work, the authors investigate the influence of doses and water content on the radiolysis of acetic acid adsorbed in a clay surface (Na-montmorillonite). The reaction was followed by the formation of CO₂, also for other non-volatile radiolytic products from ¹⁴C-acetic acid. The main reaction observed was a decarboxylation reaction. The mechanism of this heterogeneous catalysis is complex. This reaction can be promoted by a loss of electrons from the carbonyl group of the acid and could be accepted by acid sites on clay. Other mechanisms that are currently under study involve energy transfer process and free radical initiator by the water radiolytic products trapped in the clay lattice