Antioxidant additive compositions and lubricating compositions containing the same

A lubricating composition comprising a major amount of base oil and a minor amount of an antioxidant composition comprising:

• (1) an organomolybdenum compound prepared by reacting:
• (a) about 1.0 mole of fatty oil having 12 or more carbon atoms;
• (b) about 1.0 to 2.5 moles diethanolamine;
• and
• (c) a molybdenum source sufficient to yield about 0.1 to 12.0 percent of molybdenum based on the weight of the complex, the reaction being carried out at about 70° to 160° C.;
• (2) an alkylated diphenylamine being
• (a) a secondary alkylated diphenylamine of the formula X—NH—Y, wherein X and Y each independently represent a substituted or unsubstituted phenyl group wherein the substituents for the phenyl group are selected form the group consisting of alkyl groups having 1 to 20 carbon atoms, alkylaryl groups, hydroxyl, carboxy and nitro groups and at least one of the phenyl groups is substituted with an alkyl group having 1 to 20 carbon atoms;
• or
• (b) the reaction reaction product of N-phenyl-benzenamine and 2,4,4-trimethylpentene;
• and
• (3) a sulfur compound selected as one or more of the group consisting of:
• (a) thiadiazole of formula (I):
• wherein R and R1 are independently selected from the group consisting of hydrogen, alkyl, hydroxyalkyl, alkylthio, phenylalkyl, alkylated phenyalkyl, terpene residue and maleic acid residue of the formula
• wherein R2 and R3 are independently selected from the group consisting of hydrogen, branched or straight chain alkyl groups and cyclic aliphatic groups, wherein at least one of R and R1 is not hydrogen;
• (b) a dithiocarbamate of formula (II),
• wherein, R4, R5, R6 and R7 which are the same of different and are hydrocarbyl groups having 1 to 13 carbon atoms;
• and R6 is an aliphatic group such as straight and branched alkylene groups containing 1 to 8 carbons;
• and
• (c) a metal dithiocarbamate formula (IV)
• wherein R13 and R14 represent branched and straight chain alkyl groups having 1 to 8 carbon atoms, M is a metal cation and n is an Integer based upon the valency of the metal cation
• wherein the amount of (1) is form about 0.1-1.0% by weight, the amount of (2) is from about 0.1-5.0% by weight and the amount of (3) is from 0.05-2.5% by weight, based on the total weight of the composition.