antioxidant additives to lubricants and to their use in lubricating compositions the additives according to the invention have the formula arar 39 n sub a r 39 y where ar and ar 39 are identical or different aromatic radicals r and r 39 which are identical or different denote a c 2 c 18 linear or branched alkylene radical x denotes an oxygen or sulphur atom or an nh group a is an integer between 0 and 5 and y is chosen from the group consisting of nr 1 r 2 where r 1 and r 2 which are identical or different denote a hydrogen atom or a c 1 c 12 alkyl alkenyl cycloalkyl or arylalkyl radical n u2550 ch ar 1 where ar 1 is an aryl radical containing at least one phenolic group nr 1 co ar 1 and str1 where r 3 denotes a saturated or unsaturated linear or branched alkyl radical application_number US 79970091 A description the aromatic nitrogen may be an amine group linked to one or two aromatic radicals ar and ar 39 ar may for example denote a phenyl naphthyl anilinophenyl or phenothiazinyl radical ar 39 being replaced by a hydrogen atom ar and ar 39 may be identical and may denote a phenyl radical the aromatic nitrogen may also form part of a heterocyclic ring in this case ar and ar 39 are linked together to form with the nitrogen to which they are attached an aromatic heterocyclic structure such as phenothiazine imidazole benzimidazole triazole or benzotriazole phenothiazine derivatives are preferably employed ar and ar 39 may be substituted by alkyl or aryl preferably c 1 c 12 radicals or by hydroxyl alkoxy alkylthio groups or a halogen r 1 and r 2 advantageously denote a.