Patent GB-989215-A (GB)
Title: New diphenylamine derivatives and their application
IPC: C11B5/00
Filed: 1963-09-02
Abstract: The invention comprises diphenylamine derivatives of the formula <FORM:0989215/C2/1> in which R is an alkoxy group, preferably of 1-4 carbon atoms, and R1 is a secondary alkyl group, preferably of 3-8 carbon atoms.  The compounds may be prepared by reductive alkylation of 4-alkoxy-41-nitro- or 4-alkoxy-41-nitroso-diphenylamines -diphenylamines in the presence of a hydrogenation catalyst, e.g. copper chromite, platinum, palladium or nickel. 4-Alkoxy-41-nitrodiphenylamines for use as starting materials may be prepared by condensing p-chloronitrobenzene with a p-alkoxyaniline or a derivative thereof, e.g. the N-formyl or N-acetyl compound. 4-Alkoxy-41-nitrosodiphenylamines may be prepared by nitrosating 4-alkoxy-diphenylamines and rearranging the N-nitroso derivatives so obtained.  Alternatively, 4-alkoxy-41-nitro-and 4-alkoxy-41-nitroso-diphenylamines may be reduced to 4-alkoxy-41-aminodiphenylamines and then alkylated. Examples are given in which (1) p-chloronitrobenzene and formyl-p-phenetidide yield 4-ethoxy-41-nitrodiphenylamine, which is condensed with acetone in a hydrogen atmosphere in the presence of palladium on carbon to yield 4-ethoxy-41-isopropyl-aminodiphenylamine; (2) 4 - ethoxy - 41-nitrodiphenylamine and 2 - octanone similarly yield 4 - ethoxy - 41 - (2 - octylamino) diphenylamine; (3) 4 - ethoxy - 41 - nitrodiphenylamine and methyl isobutyl ketone similarly yield 4-ethoxy - 41 - (4 - methylpentyl - 2 - amino) diphenylamine; (4) 4 - methoxy - 41 - nitrodiphenylamine (from p - chloronitrobenzene and p - anisidine) is hydrogenated in the presence of palladium on carbon to yield 4-methoxy - 41 - aminodiphenylamine, which is reacted with acetone in a hydrogen atmosphere in the presence of palladium on carbon to yield 4 - methoxy - 41 - isopropylaminodiphenylamine; (5) 4-isopropoxydiphenylamine is nitrosated with sodium nitrite and sulphuric acid, and the product is rearranged by treatment with hydrogen chloride to yield 4-isopropoxy - 41 - nitrosodiphenylamine, which is then catalytically hydrogenated to yield 4-isopropoxy - 41 - aminodiphenylamine; this product is reacted with acetone as described in Example 4 to yield 4-isopropoxy-41-isopropylaminodiphenylamine. The products are useful as antioxidants (see Divisions C3 and C5).ALSO:As antioxidants for rubber compositions, use is made of diphenylamine derivatives of the formula <FORM:0989215/C3/1> in which R is an alkoxy group and R1 is a secondary alkyl group (see Division C2). Specified diphenylamine derivatives include 4-methoxy-41-isopropylaminodiphenylamine, 4-ethoxy - 41 - (2-octylamino)diphenylamine and 4 - isopropoxy - 41 - isopropylaminodiphenylamine.ALSO:As antioxidants for edible fats and oils and gasoline, use is made of diphenylamine derivatives of the formula <FORM:0989215/C4-C5/1> in which R is an alkoxy group and R1 is a secondary alkylgroup (see Division C2). Specified diphenylamine derivatives include 4 - methoxy - 41 - isopropylaminodiphenylamine, 4 - ethoxy - 41 - (2 - octylamino diphenylamine and 4 - isopropoxy - 41 - isopropylaminodiphenylamine.