This paper presents results of research on the process of forming gums in gasoline resulted from the pyrolysis of the ethane composition: propane, in a proportion of 1 : 3 in weight, at a temperature of 8200C. In addition, it has been researched the thermal stability of these inhibitors by the thermo-gravimetric analysis (TGA). From the TGA thermo-grams, there were appreciated the temperatures of the losses in weight during the heating process. It was found that the presence of inhibitors does not prevent from the formation of the peroxide radicals, but it prevents from their initiation of the reaction chains. The phenols efficiency is improved by alkylation in the positions 2, 4 and 6. The good results are obtained for the substitutes in all the three positions with a methyl group in para and at least a group of t-butyl in position orto comparing with the hydroxyl
