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Method for producing aromatic carboxylic acid by m-xylene and ethylbenzene multi-step co-oxidation

A technology for meta-xylene and aromatic carboxylic acids, applied in chemical instruments and methods, separation/purification of carboxylic acid compounds, preparation of carboxylate, etc., can solve problems such as difficult to generate phenylacetic acid, difficult to implement, and separation

Active Publication Date: 2016-11-30
ZHEJIANG UNIV
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Problems solved by technology

Although the melting points of the four aromatics are significantly different, they can theoretically be separated by cryogenic crystallization, but the system has multiple multi-component eutectic points, making it difficult to separate them by crystallization. This has been reported in many monographs and literatures
However, in fact, benzoic acid is generally generated after ethylbenzene is oxidized, and it is difficult to generate phenylacetic acid. The proposed scheme is difficult to implement, and the use of the mixed polycarboxylic acid generated is also very limited.

Method used

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  • Method for producing aromatic carboxylic acid by m-xylene and ethylbenzene multi-step co-oxidation
  • Method for producing aromatic carboxylic acid by m-xylene and ethylbenzene multi-step co-oxidation
  • Method for producing aromatic carboxylic acid by m-xylene and ethylbenzene multi-step co-oxidation

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Embodiment Construction

[0075] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are intended to facilitate the understanding of the present invention, but do not limit it in any way.

[0076] 1. Production of m-xylene

[0077] Such as figure 1 As shown, a typical PX production unit uses naphtha reforming method to produce aromatics and adsorption method to separate PX from C8 aromatics. The main process includes two modules: adsorption separation and isomerization. Containing the C 8 aromatics mixture S100 of the composition shown in Table 1 and the equilibrium stream S104 output by the isomerization unit, it is mixed and sent to the PX adsorption unit U101 together, and after adsorption and separation, the PX product with a purity of 99.5% is obtained, which is produced by the stream S101 The output system, the raffinate S102 is sent to the isomerization reactor U102 to conv...

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Abstract

The present invention discloses a method for producing aromatic carboxylic acid by m-xylene and ethylbenzene multi-step co-oxidation. The method includes the following steps of: (1) rectifying p-xylene raffinate containing p-xylene, m-xylene, o-xylene and ethylbenzene to remove o-xylene and obtain mixture A containing o-xylene and ethylbenzene; (2) subjecting the mixture A to multi-step oxidation to produce a mixture B containing isophthalic acid and benzoic acid, and separating the mixture B by crystallization to obtain a crude product of isophthalic acid and crystallizing mother solution to obtain benzoic acid by evaporation and concentration; (3) washing the crude product of isophthalic acid using acetic acid and distilled water respectively and drying to obtain refined isophthalic acid. The steps of the production process and each unit operation are simple and feasible. In the meantime, the method has no organic wastewater discharged, and is a new economic and environmental protection process.

Description

technical field [0001] The invention relates to a method for producing aromatic carboxylic acid, in particular to a method for producing aromatic carboxylic acid through multi-step co-oxidation of m-xylene and ethylbenzene. Background technique [0002] Purified isophthalic acid (PIA) 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 PIA 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 PIA. Various oxidation and refining methods are described in detail in the review literature (Process Economics Program Report 9E, Terephthalic Acid and DimethylTerephthalate, SRI Consulting, Menlo Park, California, 94025, January 1997.), and the literature (He Zuoyun, m-xylene and m-benzene ...

Claims

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Application Information

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IPC IPC(8): C07C51/265C07C51/43C07C51/42C07C63/24C07C63/06C07C7/04C07C15/08
CPCC07C7/04C07C51/265C07C51/42C07C51/43C07C63/24C07C63/06C07C15/08
Inventor 李希成有为宁术余
Owner ZHEJIANG UNIV
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