Diaryl amine antioxidants prepared from branched olefins
Diaryl amines are selectively alkylated by reaction with branched olefins, which olefins are capable of forming tertiary carbonium ions and can be conveniently prepared from readily available branched alcohols. The diaryl amine products are effective antioxidants and often comprise a high amount of di-alkylated diaryl amines and a low amount of tri- and tetra-alkylated diaryl amines.
1. A diaryl amine antioxidant composition comprising two or more compounds of formula II:
wherein each R is independently selected from the group consisting of H and C 1-16 alkyl; each G is independently H or C 1-16 alkyl, with the proviso that at least one G is a group of formula IV
wherein R 1 is C 1-6 alkyl and R 2 is C 1-8 alkyl, wherein the total number of carbon atoms in R 1 and R 2 combined is from 2 to 12 with the proviso that neither of R 1 and R 2 is tertiary alkyl, wherein at least 90% by weight, based on a total weight of the diaryl amine antioxidant composition, is mono para alkylated phenyl-α-naphthylamine.
2. The diaryl amine antioxidant composition according to claim 1 wherein R is selected from the group consisting of H and C 1-12 alkyl.
3. The diaryl amine antioxidant composition according to claim 2 wherein R is H.
4. A method for alkylating a diaryl amine to produce a diaryl amine antioxidant composition, the method comprising reacting a diaryl amine of formula
wherein each Ar is independently phenyl or naphthyl, wherein each phenyl or naphthyl independent of each other is unsubstituted or substituted by one or more C 1-16 alkyl, with one or one or more olefins of formula V, Va and/or Vb
to provide a diaryl amine substituted on either or both Ar groups by one or more alkyl group containing from 6 to 16 carbon atoms of formula IV:
wherein in each of formula IV and V, R 1 is C 1-6 alkyl, and R 2 is C 1-8 alkyl, wherein the total number of carbon atoms in R 1 and R 2 combined is from 2 to 12, with the proviso that neither of R 1 and R 2 is tertiary alkyl, wherein at least 90% by weight, based on a total weight of the diaryl amine antioxidant composition, is mono para alkylated phenyl-α-naphthylamine.
5. The diaryl amine antioxidant composition according to claim 1 further comprising one or more diaryl amines which are not a compound of formula II.
6. The diaryl amine antioxidant composition according to claim 5 comprising from 10 to 90% by weight of two or more compounds of formula II and from 10 to 90% by weight of one or more diaryl amines not of said formula II, based on the total weight of all diaryl amine compounds in the diaryl antioxidant composition.
7. The aromatic amine antioxidant composition according to claim 1 further comprising one or more compounds of formula XIa and/or XIb
wherein G′ is C 1-16 alkyl, with the proviso that G′ in each is not a group of formula IV.