Method of cracking waste PTFE (polytetrafluoroethylene) to obtain carbonyl fluoride

A technology of PTFE and carbonyl fluoride, which is applied in the field of cracking waste PTFE into carbonyl fluoride, which can solve the problems of difficult separation process and complicated products, and achieve the effects of expanding preparation channels, simple reaction operation and less by-products

Inactive Publication Date: 2019-05-10
天津长芦新材料研究院有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The products of pyrolysis method are complex, and there are great difficulties in the subsequent separation process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] PTFE particles with a particle size of less than 1 micron and oxygen are fed into a tube furnace preheated to 800°C at a mass ratio of 1:3 for reaction, wherein the feed rate of PTFE particles is 1.2g / min, and the reaction furnace tube It is 10m long and has an inner diameter of 6mm. The reaction pressure is 0.5 bar. After the reaction gas is cooled by air, it is slowly passed into anhydrous methanol. The carbonyl fluoride here must fully react with methanol, and at least 2 times the molar amount of carbonyl fluoride in methanol can satisfy the 1:1 reaction. In order to ensure that the final data is accurate, to ensure that all gases and anhydrous methanol carry out sufficient contact reaction (the same below); after the reaction mixture is washed and dried with water, GC is processed, and it is found that more than 94% are dimethyl carbonate, and the remaining 3% is perfluoroacetyl fluoromethyl ester and the remaining 3% is carbon tetrafluoride. (If no special instru...

Embodiment 2

[0022] Blow 10-20 micron PTFE particles into the tube furnace, and at the same time feed oxygen with a mass ratio of 8:1 to PTFE powder particles, where the feed rate of PTFE particles is 0.5g / min, and preheat to 1000 The reaction is carried out in a tube furnace at ℃, and the reaction pressure is normal pressure; the tube length of the reaction furnace is 10m, and the inner diameter is 6mm. After the reaction gas was cooled by air, it was slowly passed into a certain amount of anhydrous methanol to ensure that all the gas and anhydrous methanol were fully contacted and reacted. After washing and drying the reaction mixture, it was processed by GC and found that More than 92% is dimethyl carbonate, 3% is perfluoroacetyl fluoromethyl ester, and 5% is carbon tetrafluoride.

Embodiment 3

[0024] PTFE powder particles of 20-50 microns and oxygen are passed into a tube furnace preheated to 1000 ° C at a mass ratio of 1:10 for reaction. The tube length of the reaction furnace is 10 m and the inner diameter is 6 mm. Wherein the feed rate of the PTFE micropowder is 0.8g / min, and the internal pressure of the tubular reactor is 1.1bar. After the reaction gas was cooled by air, it was slowly passed into a certain amount of anhydrous methanol to ensure that all the gas and anhydrous methanol were fully contacted and reacted. After washing and drying the reaction mixture, it was processed by GC and found that 90% is dimethyl carbonate, the remaining 4% is perfluoroacetyl fluoromethyl ester, 3% is perfluoropropionyl fluoride, and 3% is carbon tetrafluoride.

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Abstract

The invention belongs to the field of fluorine chemical industry and particularly relates to a method of cracking waste PTFE (polytetrafluoroethylene) to obtain carbonyl fluoride. The method comprisesthe steps of (1) subjecting waste PTFE to surface treatment, to be specific, washing away hydrocarbon oil stain from the surface of PTFE, and drying; (2) cutting PTFE into powdery particles with a size of less than 100 micrometers; (3) blowing the PTFE particles into a reaction furnace with 500-1500 DEG C, introducing oxygen, and thermally oxidatively cracking PTFE to obtain carbonyl fluoride. The method herein has the advantages that waste PTFE can be oxidatively cracked to obtain carbonyl fluoride in the presence of oxygen, byproducts are few, the subsequent product has low separation requirements, the utilization rate of carbon and fluorine atoms is greatly increased, the reaction operation is simple, safety is greatly improved, and the method helps expand the preparation channels of carbonyl fluoride.

Description

technical field [0001] The invention belongs to the field of fluorine chemical industry, and in particular relates to a method for cracking waste PTFE into carbonyl fluoride. Background technique [0002] Polytetrafluoroethylene (PTFE), commonly known as the "King of Plastics", has a unique position in plastic materials due to its excellent chemical resistance, thermal stability, dielectric properties, self-lubricating properties and aging resistance. There are about 1000t of waste PTFE to be recycled. PTFE is extremely stable and will not degrade in the environment for decades. The current market price of waste PTFE is 5-10 yuan / kg. Therefore, recycling waste PTFE not only has high economic value, but also has far-reaching environmental protection significance. [0003] Due to its special properties, PTFE has a high melt viscosity and hardly flows when it reaches the melting point. Therefore, it cannot be recycled by melt polymerization and injection molding like ordinary...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/00C01B32/10C07C68/00C07C69/96C07C67/00C07C69/63
Inventor 肖鑫冀汝南于颖
Owner 天津长芦新材料研究院有限公司
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