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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

Inactive Publication Date: 2014-06-04
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the main oxidation temperature of this method is too low, and the heat of reaction is difficult to be used effectively; at the same time, the secondary oxidation time is too long, and the efficiency is low
[0009] According to patent and literature search, various existing methods for CTA purification through multi-stage oxidation or aging have different degrees of problems, and there is no report on the use of step-by-step temperature-rising oxidation for CTA purification.

Method used

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

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Embodiment 1

[0028] Medium-purity terephthalic acid production is carried out according to the method given by the present invention, according to figure 1 The relevant process parameters, results and related indicators of each unit are introduced in the sequence of the flow process, and the related process parameters, results and related indicators obtained are as follows:

[0029] 1. Main oxidation reaction unit

[0030] Table 1 Process conditions of the main oxidation reactor

[0031] temperature pressure PX processing capacity Catalyst concentration / ppm ℃ MPa t / h Co / Mn / Br 190 1.20 48.36 600 / 640 / 900 Feed HAC / PX air velocity Condensate Reflux Temperature dwell time mass ratio (kg / s) ℃ min 4.90 64 161 64

[0032] Table 2 Output indicators of the main oxidation reactor

[0033] PX conversion rate TA yield Solid holdup 4-CBA concentration in mother liquor Water content of mother liquor % % % ppm % ...

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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.

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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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C63/26C07C51/487
CPCY02P20/50Y02P20/584
Inventor 李希王丽军宋明焱成有为
Owner ZHEJIANG UNIV
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