GB907403A - Rubber antiozonants - Google Patents

Abstract

Rubber contains as an antiozonant a substituted aniline of the general formula <FORM:0907403/IV(a)/1> in which R1 represents an aliphatic or an aralkyl group, R2 represents an alkyl or a cycloalkyl group, R3 and R4 represent alkyl groups, and in which the benzene ring may be further substituted by an alkyl group, and their salts. The rubber preferably contains 0,1 to 5% by weight of the antiozonant and examples relate to the use of 2,6-dimethyl-N-isopropyl-4-ethoxy-aniline and 2,6-dimethyl-N-s. butyl-4-ethoxy-aniline in vulcanized compositions based on smoked sheet rubber and of the latter compound in a vulcanized composition based on pale crepe rubber. The compound 2,6-dimethyl-4-methoxy-N-n-octylaniline is disclaimed.ALSO:The invention comprises compounds of the general formula <FORM:0907403/IV (b)/1> in which R1 represents an aliphatic or an aralkyl group, R2 represents an alkyl or a cycloalkyl group, R3 and R4 represent alkyl groups, and in which the benzene ring may be further substituted by an alkyl group, and their salts. The compounds may be prepared by reductive alkylation of the corresponding primary amine in the presence of an aldehyde or ketone from which the group R2 may be derived by reduction. The secondary amines may be converted into acid addition and quaternary ammonium salts in the usual manner. R1 is preferably an alkyl, cycloalkyl, chloroalkyl, alkoxyalkyl, alkoxycarbonylalkyl or benzyl group, R2 preferably a secondary alkyl or a cycloalkyl group and R3 and R4 alkyl groups containing up to 5 carbon atoms. Examples describe the preparation of 2,6-dimethyl-N-5-butyl- and isopropyl-4-ethoxy-aniline from 2,6-dimethyl-p-phenetidine, itself prepared by coupling 3,5-xylenol with benzene diazonium chloride, followed by ethylation and reduction. 2,6-dimethyl-4-methoxy-N-n-octyl aniline is disclaimed.