Preparation method of 4-aminodiphenylamine

Abstract

The invention discloses a preparation method of 4-aminodiphenylamine, wherein a self-made mixture of bis-quaternary ammonium base and tetramethylammonium hydroxide with low price and good heat stability is used as a base catalyst for a condensation reaction of nitrobenzene and aniline. The bis-quaternary ammonium base has the structure of a general formula (I), wherein R1 and R2 are mutually independent alkyls of C1-C18 and preferentially of methyl, ethyl, n-propyl, isopropyl, allyl, butyl or dodecyl; R3, R4, R5 and R6 are mutually independent straight chain or branch chain alkyls of C1-C6 and preferentially of methyl, ethyl or propyl; and R7 is an alkylene or alkoxy substituted alkylene of C2-C6 and preferentially of ethylidene, propylidene, 2-methoxypropylidene, 2-ethyoxylpropylidene orbutylidene. The preparation method has the advantages that the selectivity of the nitrobenzene in the condensation reaction and the yield of the 4-aminodiphenylamine are high; the hydrogenation speedof a base-containing condensation liquid is high; a hydrogenation liquid has high layering speed and no emulsification phenomenon; and the base has good stability and is not easy to disintegrate, thereby the recovery rate of the base catalyst is improved and the production cost is reduced.

Description

technical field The present invention relates to a method for preparing 4-aminodiphenylamine, especially a method for preparing 4-aminodiphenylamine by mixing a novel self-made diquaternary ammonium base with tetramethylammonium hydroxide as a catalyst for the condensation reaction of nitroaniline method. Background technique 4-aminodiphenylamine (4-aminodiphenylamine), also known as RT base, is mainly used in the production of p-phenylenediamine rubber antioxidants 4010NA, 4020, etc. There are more than ten kinds of production methods for 4-aminodiphenylamine, and the currently industrialized methods mainly include aniline method, formanilide method, diphenylamine method and nitrobenzene method. These several methods all first synthesize 4-nitrodiphenylamine or 4-nitrosodiphenylamine, and then reduce to obtain 4-aminodiphenylamine. The nitrobenzene method produces 4-aminodiphenylamine, that is, nitrobenzene and aniline are condensed in the presence of a base catalyst to...

AI Technical Summary

Problems solved by technology

(1) the selectivity of condensation reaction nitrobenzene and the yield of 4-aminodiphenylamine are not high;

(2) The hydrogenation rate of the alkali-containing condensation liquid is relatively slow;

(3) The stratification speed of the hydrogenation liquid is slow and there is emulsification;

(4) the rate of recovery of tetramethylammonium hydroxide is on the low side

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