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Method and apparatus for producing isophthalic acid by m-xylene oxidization

A technology of isophthalic acid and m-xylene, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of reducing oxygen partial pressure, increasing consumption of acetic acid and raw materials, and increasing colored impurities, etc. The effect of reducing the production of by-products

Active Publication Date: 2017-01-25
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Excessively high oxidation temperature tends to produce more by-products, leading to increased consumption of acetic acid and raw materials. Therefore, the development trend of PTA technology in the past three decades has been towards lowering the temperature.
Of course, reducing the pressure of the reactor can also promote evaporation and reduce the temperature, but at the same time it will also reduce the partial pressure of oxygen, increase the generation of colored impurities, and affect product quality

Method used

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  • Method and apparatus for producing isophthalic acid by m-xylene oxidization

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Example 1: Oxidation of m-xylene alone, internal cooling and heat transfer

[0043] MX with a purity of 99.5% is still used to oxidize IPA as a raw material. The pressure and catalyst conditions are the same as in Comparative Example 1. The weight ratio of solvent and MX in the feed of oxidation reactor U201 is adjusted to 4: 1, and the residence time is extended to 83 Minutes, open the feed valve of the cooling water S201C of the cooling coil, control the flow of cooling water so that the heat load borne by the cooling heat transfer accounts for 12% of the total heat release of the oxidation reaction, and the remaining 88% of the heat is still removed by solvent evaporation, which is converted into To generate 1 ton of IPA, 0.385 tons of cooling water is required to produce the same amount of medium-pressure steam.

[0044] The coil heat exchanger is arranged inside the gas-liquid-solid mixture with an area density of 0.8m 2 / m 3 , the heat transfer temperature diffe...

Embodiment 2

[0048] Example 2: Co-oxidation of m-xylene and ethylbenzene, internal cooling and coordinated heat transfer

[0049] The naphtha reforming method is used to produce aromatics, the adsorption method is used to separate p-xylene (PX) from C8 aromatics, and the raffinate after the adsorption method is used to separate PX is removed by rectification to remove o-xylene (OX) to obtain The rectifying tower overhead mixture comprises the following components in mass percentage: m-xylene (MX) 91.5%, ethylbenzene (EB) 7.5%, p-xylene (PX) 0.7%, o-xylene (OX) 0.3%.

[0050] This mixture rich in MX and low in EB was co-oxidized as an API to produce isophthalic acid and benzoic acid. The generation of benzoic acid forms a mixed solvent of acetic acid-benzoic acid, which increases the solubility of isophthalic acid, further reduces the partial pressure of acetic acid, and increases the necessity of using coil cooling to remove heat.

[0051] Such as figure 1 As shown, the mixture S200A of ...

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Abstract

The invention discloses a method and apparatus for producing isophthalic acid by m-xylene oxidization, wherein the method comprises: feeding m-xylene material, an organic solvent and a catalyst into an oxidizing reactor, carrying out liquid oxidization under the action of oxygen-bearing gas to obtain mixture A containing isophthalic acid, and post-processing the mixture to obtain isophthalic acid; a cooling coil is mounted in the oxidizing reactor, and coil cooling and solvent evaporation are employed to cooperate in transferring heat during oxidative reaction; the method controls suitable reaction conditions such that isophthalic acid generated in m-xylene oxidization process is fully dissolved in a liquid, coil cooling and solvent evaporation cooling are combined in cooperation such that reaction temperature in the oxidizing reactor is significantly reduced with the pressure kept unchanged or increased, les byproducts are produced, and high-quality medium-pressure steam can be acquired through cooling heat exchanging.

Description

technical field [0001] The invention relates to a production method of aromatic dicarboxylic acid, in particular to a method and device for producing isophthalic acid by oxidation of m-xylene. Background technique [0002] Purified isophthalic acid (IPA) is the raw material of polyester resin, mainly used in the preparation of polyester bottle flakes, fibers, unsaturated resins, and low-melting point polyester products. The production method of IPA is to use m-xylene (MX) as raw material, obtain crude isophthalic acid (CIA) through liquid-phase oxidation, and then remove trace impurities in the product through hydrogenation refining to obtain polymer grade IPA. Various oxidation and refining methods are described in detail in the review document [1] (Process Economics Program Report 9E, Terephthalic Acid and DimethylTerephthalate, SRI Consulting, Menlo Park, California, 94025, January 1997), document [2] (He Zuoyun, Production technology of m-xylene and isophthalic acid, Sy...

Claims

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Application Information

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IPC IPC(8): C07C51/265C07C63/24B01J19/00B01J19/24
CPCB01J19/0013B01J19/24B01J2219/00058B01J2219/00065B01J2219/00081B01J2219/00108B01J2219/00128C07C51/265C07C63/24
Inventor 李希成有为宁术余
Owner ZHEJIANG UNIV
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