Antiozonierungsmittel

摘要

1,146,517. p-Phenylenediamine derivatives. MONSANTO CHEMICALS Ltd. 3 Oct., 1967 [3 Nov., 1966], No. 49343/66. Heading C2C. [Also in Division C3] The invention relates to p-phenylenediamine derivatives of the general formula where R is a secondary alkyl or cycloalkyl group of up to 8 carbon atoms, R1 is a secondary alkyl, cycloalkyl or aryl group of up to 8 carbon atoms, and each of R2 and R3 is an alkyl group of up to 5 carbon atoms, provided that the total number of carbon atoms in R, R1, R2 and R3 is not greater than 20. Compounds claimed per se 2,5-dimethyl-NN1-diisopropylp-phenylenediamine and 2,5-dusopropyl -N ,N1 - diisopropyl-p-phenylenediamine. The compounds in which R and R1 are secondary alkyl or cycloalkyl groups are prepared by the reductive alkylation of a phenylenediamine of the general formula where each of R2 and R3 is an alkyl group of up to 5 carbon atoms or a precursor from which the phenylenediamine can be derived by reduction, with the ketone appropriate for the introduction of the groups R and R1. The compounds in which R is secondary alkyl or cycloalkyl group and R1 is an aryl group are prepared by the reductive alkylation of a phenylene diamine of a formula where R1 is an aryl group of up to 8 carbon atoms and each of R2 and R3 is an alkyl group of up to 5 carbon atoms, with the ketone appropriate for the introduction of the group R. The reductive alkylation in each case is preferably carried out using molecular hydrogen in the presence of a hydrogenation catalyst, e.g. a noble metal. In an example, N,N1- diisopropyl - 2,5 - diethyl - p - phenylenediamine is prepared by reacting 2,5-diethyl-p-nitroaniline prepared from 2,5-diethylacetanilide via 2,5-diethyl-4-nitro acetanilide with acetone in hydrogen under pressure in the presence of platinium on a carbon catalyst. Several other examples are given.