Preparation method of dialkyl p-phenylenediamine and anti-aging agent mixture

The method of synthesizing N,N′-dialkyl-p-phenylenediamine in one step by liquid feeding and low-temperature, low-pressure hydrogenation reaction solves the problems of poor selectivity and high cost in the existing process, and realizes the production of dialkyl-p-phenylenediamine with high efficiency and low cost.

CN121824324APending Publication Date: 2026-04-10SENNICS CO LTD +1
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Patent Information

Application Number
CN202610006167.1
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-01-05
Publication Date
2026-04-10

AI Technical Summary

Technical Problem

The existing synthesis process for dialkyl-p-phenylenediamine suffers from poor selectivity, numerous byproducts, and high production costs.

Method used

N,N′-dialkyl-p-phenylenediamine is synthesized in one step via hydrogenation reaction using liquid p-nitroaniline and p-phenylenediamine as raw materials such as cyclohexanone in the presence of palladium or platinum catalysts. The process is carried out under controlled low temperature and low pressure conditions to avoid the use of additional solvents and heating, and uses liquid feeding and filtration separation processes.

Benefits of technology

It achieves highly selective (over 98%), high conversion rate and low cost synthesis of N,N′-dialkyl-p-phenylenediamine, simplifies the production process and reduces energy consumption and byproduct generation.

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Abstract

The invention discloses a method for synthesizing N, N '-dialkyl p-phenylenediamine as shown in a formula (I) or a mixture thereof and an anti-aging agent mixture produced by adopting the method. Comprising the following steps: adding a raw material A selected from paranitroaniline and p-phenylenediamine, a raw material B selected from a compound as shown in a formula (II), a compound as shown in a formula (III) and cyclohexanone, and a catalyst into a reaction device, and carrying out hydrogenation reaction under a hydrogen condition to obtain N, N '-dialkyl p-phenylenediamine as shown in a formula (I) or a mixture thereof, wherein the raw material A and the raw material B are fed in a liquid form; in the formula (I), the formula (II) and the formula (III), R1, R2, R3 and R4 are respectively and independently H or C1-C6 alkyl, or-CHR1R2 and-CHR3R4 are independently cyclohexyl. According to the method disclosed by the invention, high-selectivity and low-cost production of the N, N '-dialkyl p-phenylenediamine can be realized, and the reaction conditions are milder and more controllable. (I) (II) (III)
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