Process for preparing terephthalic acid and ethane diacid by degrading waste polyethylene glycol terephthalate plastic

A technology of polyethylene terephthalate and terephthalic acid, applied in chemical instruments and methods, bulk chemical production, carboxylate preparation, etc., can solve problems such as environmental pollution and waste of resources, and achieve high Economic benefit, low cost of degradation, and mild reaction conditions

Inactive Publication Date: 2008-10-15
ZHEJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The rapid development of the polyester industry is accompanied by a sharp increase in polyester waste. For example, in just a few years, my country has formed a huge beverage market, and

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Add the liquid-solid reaction mixture into a titanium autoclave with a volume of 500 ml, pass nitrogen gas as a protective gas, and heat the reaction mixture to 190° C. and pressure to 2.0 MPa while stirring. The composition of the liquid-solid reaction mixture was 290 g acetic acid, 10 g p-xylene (PX), 20 g PET solids and 3.75 g catalyst. The added catalyst consisted of: 0.76 g of cobalt acetate tetrahydrate, 0.76 g of manganese acetate tetrahydrate and 2.23 g of hydrogen bromide (47% strength aqueous solution). The degradation reaction was carried out at a temperature of 190°C and a pressure of 2.0 MPa. During the reaction process, high-pressure air was continuously introduced, and the constant air flow rate was 8 L / min. After 120 minutes, the reaction was terminated, and the reaction liquid sample was analyzed by capillary gas chromatography to determine the composition of its oxidative degradation small molecule product. The instrument used is Shimadzu GC-9A gas ch...

Embodiment 2

[0021] The oxidative degradation reaction of PET was carried out in the same manner as in Example 1, except that the solvent system used in Example 2 was a mixture of acetic acid and water, and the solvent composition was 270 g of acetic acid and 20 g of water. The reaction was terminated after 120 minutes of degradation, and the production amount of terephthalic acid and oxalic acid products could be measured by capillary gas chromatography. The results are shown in Table 1.

[0022] Table 1 Degradation reaction results under different solvent system composition conditions

[0023]

example

Solvent Composition Acetic acid: water: paraxylene

Benzene (g:g:g)

temperature

(℃)

Terephthalic acid

(%)

Oxalic acid

(%)

1

290∶0∶10

190

75

95

2

270∶20∶10

190

80

95

[0024] * The yield of terephthalic acid (%) refers to the percentage of the actual...

Embodiment 3

[0027] The oxidative degradation reaction of PET was carried out in the same manner as in Example 1, except that the degradation temperature and pressure conditions used in Example 3 were different. The degradation temperature used in Example 3 was 160° C. and the pressure was 1.0 MPa. The reaction was terminated after 120 minutes of degradation, and the yields of terephthalic acid and oxalic acid were determined to be 65% and 85%, respectively, by capillary gas chromatography.

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PUM

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Abstract

The invention discloses a method for producing diethylene glycol terephthalate and oxalic acid by degrading the waste polyethylene glycol terephthalate plastic. The method adopts soluble cobalt salt, manganese salt, zirconium salt, cerium salt and bromide and organic base as the catalysts (zirconium salt and cerium salt as the promoters), paraxylene as the pro oxidant, the catalysts and the pro oxidant are mixed with waste PET plastic and indifferent solvent proportionally, and under the conditions of the temperature of 100 to 350 DEG C and the pressure of 0.4 to 4.0 MPa, oxidative degradation is performed to the waste PET by adopting the gas containing oxygen molecule to produce diethylene glycol terephthalate and oxalic acid. The reaction conditions are mild; the reaction rate is high; the conversion rate is high; the method has the social benefit to solve the problem of white pollution; the diethylene glycol terephthalate and oxalic acid, and other fine chemically raw materials can be produced to obtain higher economic benefit; and the method has the advantages that the degradation cost is low, and the added value of the degradation products is high, etc.

Description

technical field [0001] The invention relates to a method for producing terephthalic acid and oxalic acid by degrading waste polyethylene terephthalate plastics. Background technique [0002] Polyethylene terephthalate (PET) plastic material has many excellent properties, so it is widely used in the manufacture and packaging of various products, such as beverage bottles, fibers, films, film bases and electrical insulation materials. The rapid development of the polyester industry is accompanied by a sharp increase in polyester waste. For example, in just a few years, my country has formed a huge beverage market, and the annual consumption of PET bottles is about 10 billion. If it is not recycled reasonably , not only cause a huge waste of resources, but also produce serious environmental pollution. After these PET waste products or disposable products become garbage, they are not easy to be decomposed by microorganisms because of their high chemical inertness, thus forming "w...

Claims

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Application Information

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IPC IPC(8): C07C63/26C07C55/06C07C51/00C07C51/21
CPCY02P20/52
Inventor 牛俊峰毛建卫李武曾翎黄娟彭勇俞跃洪
Owner ZHEJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY
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