Catalytic depolymerization process of poly-glycol telephthalate unde microwave irradiation

A technology of polyethylene terephthalate and microwave radiation, which is applied in chemical instruments and methods, preparation of carboxylate/lactone, organic chemistry, etc., can solve problems such as harsh reaction conditions, and achieve mild reaction conditions, The effect of reducing the activation energy and increasing the reaction rate

Inactive Publication Date: 2007-11-07
WENZHOU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method needs to be carried out under higher temperature and pressure conditions, and the reaction conditions are harsher.

Method used

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  • Catalytic depolymerization process of poly-glycol telephthalate unde microwave irradiation

Examples

Experimental program
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Effect test

experiment example 1

[0026] Put PET pellets, water, and magnesium oxide catalyst into the reactor, the weight ratio of PET and water is 1:10, and the weight ratio of magnesium oxide catalyst accounts for 1.5%; the reaction temperature is set to 200°C, the reaction pressure is 1.2MPa, and the microwave power is 250W, after depolymerization for 150min, cool for 20min; filter the depolymerization product, wash the solid with a small amount of deionized water, dry the solid to constant weight; distill the filtrate to obtain the EG product; dissolve the crude TPA with 0.5mol / L NaOH solution, add Diluted with hydrochloric acid equivalent to sodium ions, filtered, washed with deionized water to remove NaCl aqueous solution, obtained pure TPA solid, dried to obtain a white refined TPA solid product, and the PET depolymerization rate reached 88.5%.

experiment example 2

[0028] Put PET particles, water, and zinc oxide catalyst into the reactor, the weight ratio of PET and water is 1:6, and the weight ratio of zinc oxide catalyst is 0.7%; set the reaction temperature to 200°C, the reaction pressure to 1.0MPa, and the microwave power to 250W, after depolymerization for 120min, cool for 20min; filter the depolymerization product, wash the solid with a small amount of deionized water, dry the solid to constant weight; distill the filtrate to obtain the EG product; dissolve the crude TPA with 0.5mol / L NaOH solution, add Hydrochloric acid equivalent to sodium ions, filtered, washed with deionized water to remove the NaCl aqueous solution, obtained a pure TPA solid, dried to obtain a white refined TPA solid product, and the PET depolymerization rate reached 82.4%.

experiment example 3

[0030] Put PET pellets, water, and manganese dioxide catalyst into the reactor, the weight ratio of PET and water is 1:12, and the weight ratio of manganese dioxide catalyst is 1.0%; set the reaction temperature to 180°C, the reaction pressure to 1.0MPa, microwave The power is 250W, after depolymerization for 100min, cool for 20min; filter the depolymerization product, wash the solid with a small amount of deionized water, dry the solid to constant weight; distill the filtrate to obtain the EG product; dissolve the crude TPA with 0.5mol / L NaOH solution , adding hydrochloric acid equivalent to sodium ions, filtering, washing with deionized water to remove the NaCl aqueous solution, and obtaining a pure TPA solid, drying to obtain a white refined TPA solid product, and the PET depolymerization rate reaches 80%.

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Abstract

The present invention is one kind of environment friendly catalytic depolymerization process of polyglycol telephthalate under microwave irradiation with mild reaction condition. The present invention features that in the presence of metal oxide as catalyst, polyglycol telephthalate and water as reaction medium in certain weight ratio are reacted at 100-200 deg.c temperature and 0-1.3 MPa pressure under microwave irradiation, so that polyglycol telephthalate is depolymerized into telephthalic acid and glycol. The metal oxide catalyst may be zinc oxide, magnesium oxide, manganese dioxide, ferric oxide or their mixture.

Description

technical field [0001] The invention relates to a catalytic depolymerization method of polyethylene terephthalate under microwave radiation. Background technique [0002] Polyethylene terephthalate (hereinafter referred to as PET) is widely used in the fields of beverage bottles, fibers, films, film bases and electrical insulation materials due to its excellent performance. According to statistics, the annual output of PET in 2005 was about 41.18 million tons in the world and 6-6.5 million tons in my country. Its scale can be compared with that of the ethylene industry. With the rapid increase in production and sales of PET polyester, more and more waste PET polyester will be discharged into nature. Although waste PET does not directly pollute the environment, it will occupy a large amount of space because of its strong chemical inertia. Allen predicts that the life cycle of PET is 16 to 48 years. Therefore, from the perspective of environmental behavior and ecological eff...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C27/00C07C31/20C07C29/00C07C63/26C07C51/09
Inventor 张东宋小芳李恺翔
Owner WENZHOU UNIVERSITY
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