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Method for producing isophthalic acid with paraxylene raffinate as raw material

A technology of isophthalic acid and p-xylene, applied in chemical instruments and methods, separation/purification of carboxylic acid compounds, preparation of carboxylate salts, etc., can solve the problems of difficult to generate phenylacetic acid, difficult to implement, and to separate

Active Publication Date: 2018-12-18
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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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.

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  • Method for producing isophthalic acid with paraxylene raffinate as raw material
  • Method for producing isophthalic acid with paraxylene raffinate as raw material
  • Method for producing isophthalic acid with paraxylene raffinate as raw material

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Embodiment Construction

[0064] 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.

[0065] 1. Production of m-xylene

[0066] Such as figure 2 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 con...

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Abstract

The invention discloses a method for producing m-phthalic acid from p-xylene raffinate. The method comprises the following steps: (1) subjecting p-xylene raffinate containing p-xylene, m-xylene, o-xylene and ethylbenzene to rectification to remove o-xylene so as to obtain a mixture A containing m-xylene and ethylbenzene; (2) oxidizing the mixture A to produce a mixture B containing m-phthalic acid and benzoic acid, carrying out crystallization to separate out a crude m-phthalic acid product and subjecting crystallization mother liquor to evaporative concentration so as to obtain benzoic acid; and (3) dissolving the crude m-phthalic acid product to obtain an aqueous solution of m-phthalic acid, subjecting the aqueous solution of m-phthalic acid to hydrofinishing and carrying out crystallization so as to obtain fine m-phthalic acid. The method can recover o-xylene in the p-xylene raffinate and produce high-purity m-xylene, produces m-phthalic acid from m-xylene, and is low in production cost.

Description

technical field [0001] The invention relates to a method for producing aromatic dicarboxylic acid, in particular to a method for producing isophthalic acid with p-xylene raffinate as raw material. 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, meta-xylene and meta-xylene Phthalic Acid Product...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/215C07C51/487C07C51/43C07C63/24C07C63/06C07C7/04C07C5/27C07C7/12C07C15/08C07C15/073
CPCC07C5/2729C07C7/04C07C7/12C07C51/215C07C51/43C07C51/487C07C63/24C07C63/06C07C15/08C07C15/073
Inventor 李希成有为宁术余
Owner ZHEJIANG UNIV