Catalytic depolymerization of PET under microwave irradiation

A microwave radiation, catalytic depolymerization technology, applied in chemical instruments and methods, organic chemistry, preparation of oxygenated compounds, etc., can solve problems such as harsh reaction conditions, and achieve the effects of mild reaction conditions, shortened reaction time, and uniform heating

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 of PET under microwave irradiation

Examples

Experimental program
Comparison scheme
Effect test

experiment example 1

[0026] Put PET particles, water, and zinc acetate catalyst into the reactor, the weight ratio of PET and water is 1:10, and the weight ratio of zinc acetate catalyst is 0.6%; set the reaction temperature to 200°C, the reaction pressure to 1.0MPa, and the microwave power to 250W, after depolymerization for 200min, cool for 20min; filter the depolymerization product, and wash the solid with a small amount of deionized water (to remove a small amount of catalyst in the solid), dry the solid to constant weight; distill the filtrate to obtain the EG product; use 0.5mol / After the NaOH solution of 1 L is dissolved, add hydrochloric acid equivalent to the sodium ion, filter, wash with deionized water to remove the NaCl aqueous solution, and obtain a pure TPA solid, dry to obtain a white refined TPA solid product, and the PET depolymerization rate reaches 89.2 %.

experiment example 2

[0028] Put PET pellets, water, and manganese acetate catalyst into the reactor, the weight ratio of PET and water is 1:12, and the weight ratio of manganese acetate catalyst is 1.0%; set the reaction temperature to 200°C, the reaction pressure to 1.0MPa, and the microwave power to 250W, after depolymerization for 150min, cool for 20min; filter the depolymerization product, and wash the solid with a small amount of deionized water (remove a small amount of catalyst in the solid), dry the solid to constant weight; distill the filtrate to obtain the EG product; crude TPA with 0.5mol / After the NaOH solution of L is dissolved, add hydrochloric acid equivalent to the sodium ion, filter, wash with deionized water to remove the NaCl aqueous solution, obtain a pure TPA solid, dry it, and obtain a white refined TPA solid product, and the PET depolymerization rate reaches 70.5 %.

experiment example 3

[0030] Put PET pellets, water, and potassium oxalate catalyst into the reactor, the weight ratio of PET to water is 1:10, and the weight ratio of potassium oxalate catalyst is 1.5%; set the reaction temperature to 150°C, the reaction pressure to 1.0MPa, and the microwave power to 250W, after depolymerization for 150min, cool for 20min; filter the depolymerization product, and wash the solid with a small amount of deionized water (remove a small amount of catalyst in the solid), dry the solid to constant weight; distill the filtrate to obtain the EG product; crude TPA with 0.5mol / After the NaOH solution of L is dissolved, add hydrochloric acid equivalent to the sodium ion, filter, wash with deionized water to remove the NaCl aqueous solution, and obtain a pure TPA solid, dry to obtain a white refined TPA solid product, and the PET depolymerization rate reaches 65.2 %.

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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 salt of organic acid 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.

Description

technical field [0001] The invention relates to a catalytic depolymerization method of PET (polyethylene terephthalate) under microwave radiation. Background technique [0002] Polyethylene terephthalate (abbreviated 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 effects, ...

Claims

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Application Information

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