Patent ID: 7816308

Claim:
A composition comprising: A) a lubricant; and B) a mixture of antioxidants, wherein said mixture is prepared by the partial condensation of an alkylated diphenylamine comprising a tri-nonylated diphenylamine with an aldehyde or ketone in the presence of an acidic catalyst to yield at least one acridan of the general formula: along with residual alkylated diphenylamine remaining after said partial condensation; wherein: R 1 , R 2 , R 3 , and R 4 are independently selected from the group consisting of hydrogen and nonyl, provided that at least three of R 1 , R 2 , R 3 , and R 4 are not hydrogen, and R 4 , and R 5 are independently selected from the group consisting of C 1 to C 20 hydrocarbyl and hydrogen; wherein, at the termination of said condensation, residual alkylated diphenylamine is not separated from the acridan product and remains in said mixture with said antioxidants.