Method for producing benzene dicarboxylic acid by mixed dimethylbenzene cooxidation

A technology for producing benzenedicarboxylic acid and mixed xylenes, which is applied in chemical instruments and methods, carboxylate preparation, organic compound preparation, etc., can solve the problems of high separation cost and separation difficulty, and achieve the reduction of separation cost, Simplify the process and improve the effect of market competitiveness

Inactive Publication Date: 2007-05-16
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Because the isomer properties of these three C8 aromatics are close, separation is difficult, and t

Method used

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  • Method for producing benzene dicarboxylic acid by mixed dimethylbenzene cooxidation

Examples

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Embodiment 1

[0030] Figure 1 is a schematic diagram of the process of co-oxidizing mixed xylenes and then obtaining benzenedicarboxylic acid by crystallization and separation. Mixed xylene raw materials containing three isomers, together with solvent acetic acid, catalyst cobalt acetate, manganese acetate and bromide, are fed into oxidation reactor 3 through feeding pipe 1, air or oxygen-containing gas is blown in through inlet pipe 2, and reaction tail gas passes through The tail gas pipe 4 is output, after being condensed by the condenser 5, part of the solvent condensate is refluxed to the reactor 3, and the rest of the tail gas is sent to the subsequent unit for treatment. Obtain the slurry that contains terephthalic acid, isophthalic acid, orthophthalic acid from the slurry outlet pipeline 7 of reactor 3, introduce in the tertiary crystallizer 8,11,14 after being heated up by heater 6, crystallization The temperature and pressure of vessels 8, 11, 14 are reduced step by step so that t...

Embodiment 2

[0045] Fig. 2 is a schematic diagram of a process for co-oxidizing a mixture of p-xylene and m-xylene after separating o-xylene. The mixed xylene raw material first passes through the rectification tower 1, and o-xylene is obtained from the bottom of the tower, and m-xylene and p-xylene are obtained after condensation at the top of the tower; the mixture of m-xylene and p-xylene is introduced into the oxidation reactor 2 together with a solvent and a catalyst, and the reaction slurry The raw material is introduced into the refining unit 3 again, and the product mixture of isophthalic acid and terephthalic acid is obtained after refining.

[0046] In this example, the reaction conditions of the oxidation reactor 2 are the same as in Example 1, the description of the feed and discharge of the reactor is listed in Table 7, and the process conditions of the refining unit 3 are listed in Table 8. What is obtained by this method is a mixture of purified terephthalic acid and purifie...

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Abstract

The invention discloses a manufacturing method of benzene dicarboxilic acid through co-oxidizing blended xylene, which comprises the following steps: adding blended xylene, acetate solvent, cobalt, magnesium, bromine three-element catalyst into oxidizing reactor; blowing air or oxygen gas; oxidizing at 150-220 Deg C under 0.5-2.5Mpa for 30-150 min; obtaining mixed benzene dicarboxilic acid slurry; separating to obtain the mixed benzene dicarboxilic acid product or pure terephthalic acid, isophthalic and phthalic acid through multi-grade crystallizing, separating and purifying.

Description

technical field [0001] The invention relates to a method for producing benzenedicarboxylic acid by co-oxidation of mixed xylenes. Background technique [0002] Phenylenedicarboxylic acid is an important raw material for the production of polyester fibers and polyester materials, among which purified terephthalic acid (PTA) is the most demanded in the market, which is used for the production of polyester; followed by isophthalic acid (PIA), which is used for used in polyester chips; phthalic acid is mainly used in the production of phthalic anhydride. These three carboxylic acids are currently produced by liquid-phase air oxidation using the three isomers of xylene, for example, terephthalic acid is obtained from the oxidation of p-xylene (PX), and terephthalic acid is obtained from the oxidation of m-xylene (MX). Isophthalic acid is obtained from the oxidation of o-xylene (OX) to phthalic acid. The oxidation conditions of these three industrial processes are very similar. ...

Claims

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Application Information

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IPC IPC(8): C07C51/265C07C63/15
Inventor 成有为王丽军张永昭李希
Owner ZHEJIANG UNIV
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