Catalytic isomerization of paraffines of low molecular weight is a very important process in petrochemical refination and zeolites like mordenites and erionites are used frequently as supports, due to acid properties, neccesary for a dual action in hydroisomerization processes(1–3). In the present work, we analyze the behavior of erionites interchanged with Pt at low weight concentrations, using test reaction for n-pentane hydrodesintegration. At several stages of the process, small quantities of the samples were studied using TEM,AEM, IR, ESCA and Auger methods.