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Terephthalic acid oxidation residue recovery and utilization method

A technology of terephthalic acid and isophthalic acid, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of low utilization rate of isophthalic acid and low product purity

Active Publication Date: 2005-05-04
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In order to solve the problems in the prior art that the utilization rate of terephthalic acid and isophthalic acid is low, the purity of the obtained product is low, etc., the invention provides a method for recycling terephthalic acid oxidation residue

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] The terephthalic acid oxidation residue contained 30% by weight of terephthalic acid, 28% by weight of isophthalic acid, and 35% by weight of benzoic acid.

[0050] Dry the above residue and pulverize it; carry out the first methyl esterification reaction between the residue after pulverization and methanol, the weight ratio of the residue to methanol is 1:1.2, the reaction temperature is 210°C, and the reaction time is 3 hours; then remove it by distillation Water and methanol in the product of the first methyl esterification reaction; then carry out the second methyl esterification reaction, remove the intermediate product of water and methanol and the weight ratio of methanol is 1:1, the reaction temperature is 200 ° C, the reaction time For 2 hours; then use the rectification method to separate the mixed ester and methyl benzoate composed of dimethyl terephthalate and dimethyl isophthalate from the second methyl esterification reaction product, and the rectification ...

Embodiment 2～5

[0055] The process of Examples 2-5 is the same as that of Example 1, and the raw material components, process parameters and results of Examples 1-5 are shown in Table 1.

[0056] process

Embodiment 6

[0058] The mixed ester composed of dimethyl terephthalate and dimethyl isophthalate obtained in Example 1 was used to prepare the mixed ester composed of dioctyl terephthalate and dioctyl isophthalate.

[0059] After mixing the mixed ester composed of dimethyl terephthalate and dimethyl isophthalate with isooctyl alcohol, add catalyst tetrabutyl titanate and heat to carry out transesterification reaction. The molar ratio of the mixed ester composed of dimethyl terephthalate and dimethyl isophthalate to isooctyl alcohol is 1:3, the reaction temperature is 200°C, the reaction time is 3 hours, and the amount of catalyst used is the total weight of the reactants 0.2%.

[0060] Then use vacuum distillation to remove isooctyl alcohol and low boilers in the transesterification reaction product, the distillation temperature is 180 ℃, and the distillation time is 3 hours, vacuum tightness-0.095MPa (gauge pressure), obtain dioctyl terephthalate and Mixed esters composed of dioctyl isop...

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PUM

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Abstract

The invention relates to a kind of recycling method of tere phthalic acid (TPA) oxidizing residue. The invention uses the processes such as twice methyl ester reaction, rectification for separating, recrystallization for refining, interesterification reaction, and so on, to recycle tere phthalic acid (TPA), M-phthalic acid, and benzoic acid in petroleum chemical industry production residue. The invention solves problems such as low recycling ratio and more impurity of the product and so on in existing technique. The method is mainly used in recycling of tere phthalic acid (TPA) oxidizing residue.

Description

technical field [0001] The invention relates to a method for recycling petrochemical production residues, in particular to a method for recycling terephthalic acid oxidation residues. Background technique [0002] Terephthalic acid is an important petrochemical product, which is the main raw material for the production of polyester. There are many ways to produce terephthalic acid in industry, among which high-temperature oxidation of p-xylene is the most important production method. The method uses p-xylene as raw material, acetic acid as solvent, cobalt acetate, manganese acetate and tetrabromoethane as catalysts, oxidizes at high temperature to generate crude terephthalic acid, and then refines it into purified terephthalic acid. [0003] There are a lot of side reactions in the process of oxidizing p-xylene to terephthalic acid. The generated by-products and unreacted raw materials enter the mother liquor, and the solid impurities produced after the mother liquor is eva...

Claims

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Application Information

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IPC IPC(8): A62D3/00C07C67/60C07C69/82
Inventor 李红剑黄秋明莫馗阙子龙彭海珠卢姝陈石登栾金义
Owner CHINA PETROLEUM & CHEM CORP
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