A PIB derivative suitable for use as a fuel additive or lubricant additive prepared from a reactive low molecular weight polyisobutylene composition comprising at least 50 mol percent alpha vinylidene terminated polyisobutylene molecules, the composition having a polydispersity of no more than 1.5 and a number average molecular weight of at least 500 Daltons and no more than 1000 Daltons. The derivative is selected from the group consisting of: alkyl hydroxyaromatic compounds; alkyl alkoxy aromatic compounds; polyisobutenylsuccinic anhydrides; polyisobutenylsuccinimides; PIB-amine compounds; sulfurized PIB compounds; and Mannich condensation products of an alkylated hydroxyaromatic compound.

A PIB derivative suitable for use as a fuel additive or lubricant additive prepared from a reactive low molecular weight polyisobutylene composition comprising at least 50 mol percent alpha vinylidene terminated polyisobutylene molecules, the composition having a polydispersity of no more than 1.5 and a number average molecular weight of at least 500 Daltons and no more than 1000 Daltons. The derivative is selected from the group consisting of: alkyl hydroxyaromatic compounds; alkyl alkoxy aromatic compounds; polyisobutenylsuccinic anhydrides; polyisobutenylsuccinimides; PIB-amine compounds; sulfurized PIB compounds; and Mannich condensation products of an alkylated hydroxyaromatic compound.

A synergistic mixture comprising from 1 to 99.9% by weight of compounds having structural elements (I) ##STR00001##
in which the free valencies on the oxygen atom and on the nitrogen atom may be combined to form a five-, six- or seven-membered ring and the benzene ring may also bear substituents at one or more of the free positions, and from 0.1 to 99% by weight of sulfur-containing organic compounds with antioxidant action. This synergistic mixture is suitable as a stabilizer for stabilizing inanimate organic material, especially mineral oil products and fuels, against the action of light, oxygen and heat.