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Method for recovering terephthalate from waste PET

A technology of terephthalate and terephthalic acid, which is applied in the field of terephthalate recovery, can solve the problems of slow reaction speed and low product yield, achieve short reaction time, low catalyst consumption, DMT The effect of high yield

Pending Publication Date: 2021-03-05
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is the problem of slow reaction speed and low product yield in the prior art. It provides a method for reclaiming terephthalic acid esters from waste PET. The method has a faster reaction speed or a higher target than the same ratio. Features of high product yield

Method used

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  • Method for recovering terephthalate from waste PET
  • Method for recovering terephthalate from waste PET
  • Method for recovering terephthalate from waste PET

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The reaction was carried out in a 500ml titanium autoclave equipped with a magnetic stirrer, a gas delivery tube, a reflux condenser, a thermocouple, and a rupture disc, with a stirring speed of 400 rpm and electric heating. The reaction steps are as follows:

[0032] 1) Weigh 10 g of waste polyester PET, 3 g of terephthalic acid, 80 g of methanol, and 0.15 g of 1,3-dimethyl imidazolium bromide, mix them evenly, add them to the autoclave, and seal them.

[0033] 2) Add 10.0MPa nitrogen to carry out the airtight test for 30 minutes, and the pressure drop within 30 minutes is not more than 0.1MPa, which is qualified.

[0034] 3) The pressure was released to normal pressure, then purged with nitrogen for 3 times, the intake switch was closed, and the stirrer was started, the stirring rate was 400rpm, the temperature was raised to 280°C, and the pressure was kept at 10.0MPa, and the reaction was carried out at 280°C for 60min.

[0035] 4) After the reaction is completed, s...

Embodiment 2

[0038] The reaction was carried out in a 500ml titanium autoclave equipped with a magnetic stirrer, a gas delivery tube, a reflux condenser, a thermocouple, and a rupture disc, with a stirring speed of 400 rpm and electric heating. The reaction steps are as follows:

[0039] 1) Weigh 10 g of waste polyester PET, 1 g of terephthalic acid, 80 g of methanol, and 0.15 g of 1,3-dimethylimidazolium bromide, mix them evenly, add them to the autoclave, and seal them.

[0040] 2) Add 10.0MPa nitrogen to carry out the airtight test for 30 minutes, and the pressure drop within 30 minutes is not more than 0.1MPa, which is qualified.

[0041] 3) The pressure was released to normal pressure, then purged with nitrogen for 3 times, the intake switch was closed, and the stirrer was started, the stirring rate was 400rpm, the temperature was raised to 280°C, and the pressure was kept at 10.0MPa, and the reaction was carried out at 280°C for 60min.

[0042] 4) After the reaction is completed, sw...

Embodiment 3

[0045] The reaction was carried out in a 500ml titanium autoclave equipped with a magnetic stirrer, a gas delivery tube, a reflux condenser, a thermocouple, and a rupture disc, with a stirring speed of 400 rpm and electric heating. The reaction steps are as follows:

[0046] 1) Weigh 10 g of waste polyester PET, 6 g of terephthalic acid, 80 g of methanol, and 0.15 g of 1,3-dimethyl imidazolium bromide, mix them evenly, add them to the autoclave, and seal them.

[0047]2) Add 10.0MPa nitrogen to carry out the airtight test for 30 minutes, and the pressure drop within 30 minutes is not more than 0.1MPa, which is qualified.

[0048] 3) The pressure was released to normal pressure, then purged with nitrogen for 3 times, the intake switch was closed, and the stirrer was started, the stirring rate was 400rpm, the temperature was raised to 280°C, and the pressure was kept at 10.0MPa, and the reaction was carried out at 280°C for 60min.

[0049] 4) After the reaction is completed, sw...

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Abstract

The invention relates to a method for recovering terephthalate from waste PET, and mainly solves the problems of low reaction speed and low product yield in the prior art. According to the technical scheme adopted in the invention, the method for recovering terephthalate from waste PET comprises the following steps of: (1) adding waste PET, terephthalic acid, alkyl alcohol and an ester exchange catalyst into a reactor to obtain an initial reaction mixture; and (2) carrying out reaction under the condition that the PET and alkyl alcohol are subjected to transesterification to obtain terephthalate. The technical problem is better solved, and the method can be used for recycling waste PET.

Description

technical field [0001] The present invention relates to a method for recovering terephthalate from waste PET. Background technique [0002] Purified terephthalic acid, commonly known as PTA, is the basic raw material for the synthesis of polyethylene terephthalate (PET), and its demand continues to grow. It is estimated that in 2018, the global demand for PTA will reach 60 million tons. At the same time, a large amount of discarded PET is also produced every year. Although the discarded PET itself is not harmful to the environment, it degrades very slowly in nature, and the accumulation is also very harmful to the environment. At present, the waste PET recycling methods mainly include physical method and chemical method. The physical method mainly uses mechanical recycling and hot melting method. The technology is not yet mature enough, the recovered product has low purity, and its use is also greatly restricted. [0003] Chinese patent CN201710017715 (a low-temperature an...

Claims

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Application Information

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IPC IPC(8): C07C67/03C07C69/82
CPCC07C67/03C07C69/82Y02W30/62
Inventor 肖忠斌杨运信
Owner CHINA PETROLEUM & CHEM CORP
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