"Pyrroles are unstable in the presence of oxygen and participate in the oxidative process by which color, gum, and sludge are formed in petroleum and shale-oil distillates (5, 6, 11, 19). This deterioration is generally more rapid and extensive in shale-oil naphtha than in petroleum naphtha, the difference being attributed in part to the substantially higher concentration of pyrrolic nitrogen in shale-oil naphtha. Autoxidation of pyrroles under mild conditions, similar to those leading to the deterioration, of distillate fuels, is, therefore, of interest in the study of gm formation. The process by which pyrroles react with oxygen has received little attention, although some products of the reaction have been identified. Succinimide was identified as a minor product of the air oxidation of pyrrole (2). Air oxidation of several carbon-substituted alkylpyrroles with free alpha positions gave products for which the peroxide structure was proposed (10). However, these substances gave no test for active oxygen, and the structure has been questioned on other grounds (14). Photo-oxidation of dilute aqueous solutions of pyrrole (1, 4) and 1-methylpyrrole (4) under very mild conditions gave products isomeric with the corresponding succinimides. This is a report of the autoxidation of 1-methylpyrrole, 1-isopropylpyrrole, and 1-butylpyrrole at 50 degrees C under one atmosphere of oxygen. Oxygen consumption rates, identification of reaction products, and appearance times of these reaction products led to inference concerning the mechanisms of the oxidation reactions."