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Terephthalic acid and water scrubbing residue recovery and utilization method

A technology for terephthalic acid and dioctyl terephthalate is applied in the field of terephthalic acid washing residue recycling and can solve the problems of low product purity, low utilization rate of terephthalic acid and p-toluic acid and the like

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

[0007] In order to solve the problems in the prior art that the utilization rate of terephthalic acid and p-toluic acid is low, the purity of the obtained product is low, etc., the invention provides a method for recycling terephthalic acid washing residue

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] The terephthalic acid washing residue contained 76% by weight of terephthalic acid and 21% by weight of p-toluic acid.

[0049] 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 rectification to separate dimethyl terephthalate and methyl p-toluate from the methyl esterification reaction product for the second time, and the overhead fraction reflux ratio is 1 in the rectification process, The number of theoretical plates is...

Embodiment 2～5

[0054] 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.

[0055] process

Embodiment 6

[0057] The dimethyl terephthalate obtained in Example 1 was used to prepare dioctyl terephthalate.

[0058] After mixing dimethyl terephthalate and isooctyl alcohol, add catalyst tetrabutyl titanate and heat to carry out transesterification reaction. The molar ratio of dimethyl terephthalate to isooctyl alcohol is 1:3, the reaction temperature is 200° C., the reaction time is 3 hours, and the catalyst consumption is 0.2% of the total weight of reactants.

[0059] Then use vacuum distillation to remove isooctyl alcohol and low boilers in the transesterification reaction product. The distillation temperature is 180° C., the distillation time is 3 hours, and the vacuum degree is -0.095 MPa (gauge pressure) to obtain the crude product of dioctyl terephthalate .

[0060] Then the crude dioctyl terephthalate is mixed with a 10% sodium carbonate solution at a volume ratio of 1:1, stirred at a temperature of 75°C for 1.2 hours, and then oil-water separation is carried out, and the oi...

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PUM

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Abstract

The invention relates to a kind of recycling method of tere phthalic acid (TPA) water-washing 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) and tere methyl 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) water-washing 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 washing 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 evapo...

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