Method for preparing p-phenylenediamine rubber aging inhibitor

Abstract

The invention discloses a method for preparing a p-phenylenediamine rubber aging inhibitor, and relates to the technical field of chemical synthesis. The method comprises the following steps of: adding 4-aminodiphenylamine and partial methyl isobutyl ketone into a condensation reaction kettle, performing condensation reaction at a certain temperature under certain pressure, removing water generated by the reaction, and obtaining a condensation solution; adding the condensation solution, a hydrogenation catalyst and replenished methyl isobutyl ketone into the reaction kettle, performing hydrogenation reaction at a certain temperature under certain pressure, and obtaining a hydrogenation solution; and performing post treatment on the hydrogenation solution to obtain the p-phenylenediamine rubber aging inhibitor 4020, wherein the hydrogenation catalyst is a nickel, palladium or platinum catalyst. From the practice of industrial production, the rubber aging inhibitor 4020 is synthesized by adopting two-step reaction of condensation and hydrogenation; the difficulty of the hydrogenation reaction is reduced; and the requirement on the catalyst is reduced. The method has mild reaction conditions, high product quality and simple flow and no pollution, and is easy to realize industrialization.

Description

technical field [0001] The present invention relates to a preparation method of rubber anti-aging agent, more specifically, relates to a method for preparing p-phenylenediamine rubber anti-aging agent 4020 through hydrogenation, reduction and alkylation of 4-aminodiphenylamine and methyl isobutyl ketone. Background technique [0002] P-phenylenediamine antioxidant is currently the most widely used type of antioxidant in the rubber industry. They can inhibit the ozone aging, fatigue aging, thermo-oxidative aging and catalytic oxidation of metal ions of rubber products. Rubber anti-aging agent 4020, the chemical name is N-(1,3-dimethylbutyl)-N'-phenylenediamine, which belongs to the anti-aging agent of p-phenylenediamine with anti-aging agent 4010NA. Solvent rubber antioxidant. In natural and synthetic rubber, it has good protective effect against ozone and flex aging; it also has good protective effect against general aging such as oxygen and heat and harmful metals such as...

AI Technical Summary

Problems solved by technology

[0010] Chinese Patent Application Publication No. CN1170711A discloses a method for synthesizing p-phenylenediamine rubber antioxidant in an autoclave. It also uses a one-step method to synthesize rubber antioxidant 4020 by condensation hydrogenation reaction at 2-10MPa and 180-250°C. Reduce the amount of MIBK (the molar ratio of RT times to MIBK is 1:1.05~1.1). Although the yield of the product is relatively good, too little amount of MIBK will cause the viscosity of the reaction solution to be particularly large and the fluidity to be poor, resulting in catalyst failure. very difficult to recycle

In addition, the amount of methyl isobutyl carbinol (MIBC) produced by the reaction is relatively large (alcohol / ketone molar ratio = 1:7), and the separation is difficult

[0011] According to the reports in the existing literature, all of them use one-step method to synthesize rubber antioxidant 4020, which needs both condensation and hydrogenation in the autoclave, so high temperature, high pressure reaction conditions and high activity and high selectivity catalysts are needed to promote The reaction is carried out, but high temperature and high pressure will cause side reactions such as hydrogenation of benzene ring and breakage of C-N bonds, resulting in low quality of 4020 products; in addition, high temperature and high pressure have relatively high requirements for equipment materials and energy consumption , the cost of industrialization is relatively large

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