Process for the synthesis of pyromellitic acid

By using a liquid-phase oxidation method in a microchannel reactor with a Co/Mn/Br catalyst to oxidize mesitylene in contact with oxygen, combined with oxidation in a reaction vessel, the problems of low yield and poor selectivity were solved, achieving high yield, low energy consumption, and reactor safety. This method is suitable for the synthesis of pyromellitic acid.

CN122102886APending Publication Date: 2026-05-29CHINA PETROLEUM & CHEMICAL CORP +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
CHINA PETROLEUM & CHEMICAL CORP
Filing Date
2024-11-28
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

Existing technologies for synthesizing pyromellitic acid have low yields, poor selectivity, and are prone to clogging in microchannel reactors. Furthermore, gas-phase oxidation methods are energy-intensive and economically unviable.

Method used

The first oxidation was carried out in a microchannel reactor using liquid-phase oxidation, where a Co/Mn/Br catalyst was used to oxidize mesitylene by contacting oxygen-containing gas. The second oxidation was then carried out in a reaction vessel. The reaction conditions, such as temperature, pressure, residence time, and catalyst ratio, were optimized, and a suitable solvent, such as acetic acid or propionic acid, was selected.

Benefits of technology

This improved the yield and selectivity of pyromellitic acid, avoided clogging of the microchannel reactor, and enabled a safe, economical, and environmentally friendly synthesis process.

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Abstract

The present application relates to the technical fields of organic chemical synthesis, and discloses a method for synthesizing pyromellitic acid. The method comprises the following steps: (1) under gas-liquid reaction conditions, contacting liquid-phase materials containing durene, a solvent and a catalyst with an oxygen-containing gas in a micro-channel reactor to perform first oxidation, so as to obtain first oxidation materials, wherein the conditions of the first oxidation are such that the conversion rate of the durene reaches more than 99%, and the total molar amount of a monocarboxyl product, a dicarboxyl product and an intermediate product of the oxidation of the monocarboxyl product to the dicarboxyl product in the first oxidation materials is more than 85% of the molar amount of the first oxidation materials; and (2) sending the first oxidation materials into a reaction kettle to perform second oxidation. The method for synthesizing pyromellitic acid provided by the present application has the advantages of high yield, good selectivity, low possibility of blockage of the micro-channel reactor, high oxidation efficiency, safe reaction, economy and environmental protection.
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