Method for catalytically degrading polyethylene glycol terephthalate

A technology of polyethylene terephthalate and polyethylene terephthalate, which is applied in the field of catalytic degradation of polyethylene terephthalate, and can solve the problems of non-recyclability and high cost of metal ionic liquid catalysts , to achieve the effect of green environmental protection, high yield and low temperature in the preparation method

Active Publication Date: 2021-07-23
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method improves the conversion rate of waste PET by using a highly selective catalyst. The disadvantage is that the cost of th...

Method used

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  • Method for catalytically degrading polyethylene glycol terephthalate
  • Method for catalytically degrading polyethylene glycol terephthalate
  • Method for catalytically degrading polyethylene glycol terephthalate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] (1) After cleaning and drying the waste PET bottles, place them in a pulverizer and pulverize them to obtain waste PET fragments with a size of 5 mm.

[0041] (2) Weigh 2g of waste PET chips and 2g of zinc hydroxide, put them into a ball mill, stir and mix at a speed of 50r / min for 20min, and obtain a homogeneous mixture of the two.

[0042] (3) Transfer the mixture obtained in step (2) to a crucible, put the crucible into a tube furnace, set the tube furnace to heat at a heating rate of 5°C / min, rise to a reaction temperature of 240°C, and Keep warm at high temperature for 60 minutes, and the amount of water vapor introduced is 0.4g.

[0043] (4) After the tube furnace is naturally cooled, the solid product in the crucible and the liquid product in the condensing device are obtained. Soak the solid product in the crucible in 0.5mol / L hydrochloric acid solution for 0.5h, and filter and separate.

[0044] The white solid in the upper layer can be washed and dried to ob...

Embodiment 2

[0046] The difference between this example and Example 1 lies in that the reaction temperature is 200° C. and the reaction time is 90 minutes, and the colorless liquid of ethylene glycol and the white powder of terephthalic acid are obtained, and the yields are 93 wt % and 92 wt %, respectively. The H NMR spectra of prepared terephthalic acid and ethylene glycol are respectively as follows figure 1 with figure 2 As shown, this indicates that the purity of the prepared terephthalic acid and ethylene glycol is very high, close to 100%.

Embodiment 3

[0048] (1) Wash and dry the waste PET bottles and place them in a shredder to obtain waste PET fragments with a size of 1 mm.

[0049] (2) Weigh 2g of waste PET chips and 8g of zinc hydroxide, put them into a ball mill, stir and mix them at a speed of 100r / min for 10min, and obtain a homogeneous mixture of the two.

[0050] (3) Transfer the mixture obtained in step (2) to a crucible, put the crucible into a tube furnace, set the tube furnace to heat at a heating rate of 10°C / min, rise to a reaction temperature of 180°C, and Keep warm at high temperature for 120min, and the amount of water vapor introduced is 0.4g.

[0051] (4) After the tube furnace is naturally cooled, the solid product in the crucible and the liquid product in the condensing device are obtained. Soak the solid product in the crucible in 0.5mol / L hydrochloric acid solution for 0.5h, and filter and separate. The white solid in the upper layer can be washed and dried to obtain terephthalic acid powder with a ...

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Abstract

The invention belongs to the technical field of chemical recovery and degradation, and particularly relates to a method for catalytically degrading polyethylene glycol terephthalate. The method comprises the following steps: (1) uniformly mixing polyethylene glycol terephthalate fragments and a catalyst to obtain a mixture; and (2) heating the mixture, carrying out degradation reaction under the combined action of water vapor and a catalyst, and obtaining a solid-phase product and a liquid-phase product after the reaction is completed; wherein the catalyst is a zinc compound. Zinc oxide or a compound which can be decomposed to generate zinc oxide in the heating process is used as a catalyst, then the zinc oxide activates a C=O bond in a PET polymer chain to generate terephthalic acid and ethylene glycol, the method is green and environmentally friendly, and a new path is provided for high-added-value conversion and reutilization of waste PET.

Description

technical field [0001] The invention belongs to the technical field of chemical recovery and degradation, and in particular relates to a method for catalytic degradation of polyethylene terephthalate. Background technique [0002] Polyethylene terephthalate (PET) is the first linear thermoplastic polymer to be industrialized, and is widely used in fibers, textile fabrics, clothing, polyester bottles, films and sheets and other products. According to statistics, the global production of PET in 2019 has exceeded 70 million tons. The vast majority of PET products are disposable consumer goods, so it is very necessary to efficiently recycle waste PET. At present, the recycling methods of waste PET mainly include physical recycling method and chemical recycling method, among which physical recycling method accounts for more than 90% of the recycling technology in my country. The technological process of the physical recovery method is simple and the equipment is easy to operate...

Claims

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Application Information

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IPC IPC(8): C07C51/09C07C63/26C07C29/09C07C31/20
CPCC07C51/09C07C29/095C07C63/26C07C31/202Y02P20/52Y02W30/62
Inventor 龚江刘宁伏佳彤何攀攀郝亮白慧颖牛冉
Owner HUAZHONG UNIV OF SCI & TECH
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