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 I:
wherein each R is independently selected from the group consisting of H and C 1-16 alkyl; each G is independently H or a C 1-16 alkyl group of formula IV, with the proviso that at least one 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, in 8% or less of all compounds of formula I, R is other than H;
in 0 to 49% of all compounds of formula I, one G is H and one G is a group of formula IV;
and in 46 to 92% of all compounds of formula I, each G is a group of formula IV.
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 unsubstituted phenyl or phenyl 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 diary 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,
to yield one or more alkylated diarylamines
wherein less than 8% of alkylated diarylamines in the composition are tri- or tetra alkylated diphenyl amines,
0 to 49% of alkylated diarylamines in the composition are mono-substituted diphenyl amines, substituted by a group of formula IV at the 4 or 4′ position,
and 46 to 92% of alkylated diarylamines in the composition are disubstituted diphenyl amines, substituted at each of the 4 and 4′ positions by a group of formula IV.
5. The diaryl amine antioxidant composition according to claim 1 further comprising one or more diaryl amines which are not a compound of formula I.
6. The diary amine antioxidant composition according to claim 5 comprising from 10 to 90% by weight of two or more compounds of formula I and from 10 to 90% by weight of one or more diary amines not of said formula I, based on the total weight of all diaryl amine compounds in the diary antioxidant composition.
7. The aromatic amine antioxidant composition according to claim 1 further comprising one or more compounds of formula Xla and/or Xlb
wherein G′ is C 1-16 alkyl, with the proviso that G′ in each is not a group of formula IV.