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Method for preparing two products of polymer grade terephthalic acid and isophthalic acid from mixed aromatic hydrocarbons

A technology of terephthalic acid and isophthalic acid, which is applied in chemical instruments and methods, preparation of organic compounds, preparation of carboxylate, etc., can solve the problem of inability to use polyester raw materials, low product purity, and inability to crystallize in water phase. To achieve high-efficiency separation and other issues, to achieve the effect of improving market competitiveness and reducing separation costs

Active Publication Date: 2020-09-08
SINOPEC YIZHENG CHEM FIBER +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese patent 200610154821.6 discloses a method for producing phthalic acid by co-oxidation of mixed xylenes to obtain mixed phthalic acid products. The patent also proposes a method for obtaining PTA and PIA through multi-stage aqueous phase crystallization separation, but aqueous phase crystallization cannot be realized Efficient separation, the purity of PTA and PIA products obtained is not high, and cannot be directly used as polyester raw materials
In addition, the removal cost of aldehyde impurities in this patent is relatively high

Method used

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  • Method for preparing two products of polymer grade terephthalic acid and isophthalic acid from mixed aromatic hydrocarbons
  • Method for preparing two products of polymer grade terephthalic acid and isophthalic acid from mixed aromatic hydrocarbons
  • Method for preparing two products of polymer grade terephthalic acid and isophthalic acid from mixed aromatic hydrocarbons

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The method provided by the present invention is used to process mixed aromatic xylene raw materials with a PX / MX ratio of 1:1 to produce two products, PTA and PIA. The organic solvent NN dimethylformamide is used for PTA purification, and the process flow is as described in the specific implementation. The process conditions of each unit equipment are listed as follows:

[0036] Table 1 Process parameters of oxidation reactor 101

[0037]

[0038] Table 2 Process parameters of oxidation reactor 102

[0039]

[0040] Table 3 Process parameters of hydrogenation reactor 201

[0041]

[0042] Table 4 Process parameters of water phase high temperature crystallization unit 301

[0043]

[0044] Table 5 Process parameters of water phase high temperature crystallization unit 302

[0045]

[0046] Table 6 Process parameters of organic solvent dissolution and recrystallization 401~402

[0047]

[0048] Table 7 Process parameters of water phase low temperature crystallizer 501

[0049]

Embodiment 2

[0051] The method provided by the present invention is used to process mixed aromatic xylene raw materials with a PX / MX ratio of 1:1 to produce two products, PTA and PIA. The organic solvent N-methylpyrrolidone is used for PTA purification, and the process flow is as described in the specific embodiment The conditions of oxidation, hydrogenation and high-temperature water crystallization are the same as those in Example 1. The purity and process parameters of the product obtained by dissolving in organic solvent and low-temperature crystallization are as follows:

[0052] Table 8 Process parameters of organic solvent dissolution and recrystallization 401~402

[0053]

[0054] Table 9 Process parameters of water phase low temperature crystallizer 501

[0055]

[0056] Compared with Example 1, the ability of using N-methylpyrrolidone to dissolve terephthalic acid is stronger in Example 2 and the complete dissolution of crude TA can be achieved with less solvent and lower temperature, b...

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Abstract

The invention discloses a method for preparing two products including polymer grade terephthalic acid and polymer grade isophthalic acid by taking mixed aromatics as a raw material. Mixed xylene raw materials with a low price are used, and benzene dicarboxylic acid applied to a polyester industry is directly produced through air oxidation, hydrofining, aqueous phase high temperature crystallization, organic solvent dissolution recrystallization and aqueous phase low temperature crystallization. The separation cost of the xylene raw materials is lowered, meanwhile, two products including the polymer grade terephthalic acid and the polymer grade isophthalic acid can be produced, and the market competitiveness of a benzene dicarboxylic acid product is improved.

Description

Technical field [0001] The invention belongs to the field of aromatic carboxylic acid production and manufacturing, and specifically relates to a method for preparing both polymer-grade terephthalic acid and isophthalic acid simultaneously through oxidation and a series of subsequent refining and separation steps using para-xylene and meta-xylene mixed aromatic hydrocarbons as raw materials. This kind of product method, the raw materials used are cheap chemical raw materials, and the product is an important polyester production polymerized monomer. Background technique [0002] Aromatic dicarboxylic acid is an important organic chemical raw material, of which the largest output is purified terephthalic acid (PTA), followed by isophthalic acid (PIA). The production methods of PTA and PIA are very similar. Both use the xylene liquid phase air oxidation method to produce terephthalic acid from p-xylene (PX). The raw material for isophthalic acid is meta-xylene (MX). At present, bot...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/265C07C51/487C07C51/43C07C63/26C07C63/24
CPCC07C51/265C07C51/43C07C51/487C07C63/26C07C63/24
Inventor 冒永生毛绪国王丽军颜辉吴国清晁殿娟谢承业
Owner SINOPEC YIZHENG CHEM FIBER