Method for preparing medium-purity terephthalic acid by gradual heating oxidation

A terephthalic acid, step-by-step heating technology, applied in chemical instruments and methods, preparation of organic compounds, preparation of carboxylate, etc. problems, to achieve the effect of eliminating the hydrorefining process, reducing the consumption of combustion side reactions, and promoting diffusion
CN102731297BInactive Publication Date: 2014-06-04ZHEJIANG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
ZHEJIANG UNIV
Publication Date
2014-06-04
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a method for preparing medium-purity terephthalic acid by gradual heating oxidation. The method comprises the steps of sending paraxylene, acetic acid solvent and cobalt manganese bromide catalyst into a main oxidation reactor for catalytic oxidation reaction; sending slurry comprising coarse terephthalic acid solid output by the main oxidation reactor to a first two-stage heating oxidation reactor and a second two-stage heating oxidation reactor sequentially to cure crystals and remove 4-CBA impurity; and crystallizing to obtain the medium-purity terephthalic acid. The method provided by the invention can omit complex refining process, reduce the water consumption and improve the energy utilization ratio.
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Description

technical field

[0001] The invention belongs to a method for producing terephthalic acid through a liquid-phase oxidation method, and more specifically, the invention relates to a method for preparing terephthalic acid with medium purity through step-by-step temperature-rising oxidation. Background technique

[0002] Terephthalic acid is an important raw material for the production of polyester (PET) fibers and resins. Currently, it is mainly produced by air liquid phase oxidation of p-xylene. The method is to dissolve the raw material p-xylene (PX) in an acetic acid solvent containing a cobalt-manganese-bromine catalyst, and pass in air or oxygen-enriched gas for oxidation to generate terephthalic acid. The typical reaction pressure is 0.6~1.6MPa, the temperature is 160~200℃, the liquid residence time is 50~130min, and the reaction heat is removed by solvent evaporation. The resulting slurry is subjected to separation and purification steps to obtain terephthalic acid prod...

Claims

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