Method for manufacturing phthalic acid/phthalic acid hydride

Abstract

Continuous method for preparing a mixture of phthalic acid and its anhydride dissolved in an aliphatic monocarboxylic acid (preferably acetic acid), comprises oxidation of o-xylene (dissolved in monocarboxylic acid) with air oxygen in the presence of a catalyst, where the method comprises many reaction steps and the molar ratio of o-xylene to the intermediate product formed from 2-methyl benzaldehyde, 2-methylbenzoic acid and phthalide lies below 1:40 in the product stream (7) supplied to the last reaction step.

Description

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AI Technical Summary

Benefits of technology

This new method allows for faster production rates while reducing the amount of residue produced by previous methods that were exposed when making certain types of chemicals like PEA or poly(phenylacetamide).

Problems solved by technology

Technological Problem addressed in this patents relates to controlling the reaction temperatures during the manufacturing of poly(p)-phenoxymaphenium), abbreviations PMNA). Existing methods involve adding water at once, but they cannot fully remove all unwanted compounds like nitrogen dioxides (NO2) without causing decomposition. Additionally, existing techniques require multiple steps involving different types of equipment such as pipes, tanks, valves, etc., making them costly and slow down overall efficiency.

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