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A kind of recovery method of by-product sodium chloride in the production process of polyphenylene sulfide

A recycling method and production process technology, applied in the field of polymer engineering, can solve the problems of removing by-products, incapable of industrial use of salt, etc., achieving the effect of low energy consumption in steps and smooth production

Active Publication Date: 2017-12-26
SICHUAN UNIVERSITY OF SCIENCE AND ENGINEERING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this process does not have a rectification dehydration process, which avoids the problem of tower plugging, the process does not remove the by-products generated in the process, such as low-molecular polymers and unreacted sodium sulfide, and the obtained solid salt contains many impurities, and cannot be directly used as industrial salt

Method used

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  • A kind of recovery method of by-product sodium chloride in the production process of polyphenylene sulfide
  • A kind of recovery method of by-product sodium chloride in the production process of polyphenylene sulfide

Examples

Experimental program
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Effect test

Embodiment 1

[0025] Take by weighing 1700Kg of crystalline sodium sulfide pentahydrate, 1430Kg of p-dichlorobenzene, 175Kg of catalyst lithium chloride, 7000Kg of solvent N-methylpyrrolidone (wherein 2000Kg is used for dissolving p-dichlorobenzene, and 5000Kg is used for dehydration), polymerized in the reactor reaction. The pre-polymerization temperature is 225±2°C, and the time is 45 minutes; the polymerization temperature is 265±2°C, and the time is 150 minutes. After the polymerization reaction is completed, the temperature of the mixed slurry is cooled to 90° C., and filtered with a continuous centrifuge to obtain filter cake and by-product slurry. Wash the filter cake with 8000Kg deionized water to obtain PPS wet material and washing water, and dry the PPS wet material in a dryer to obtain the finished PPS product. Mix the washing water with the above-mentioned filtrate, and then settle in the settling tank, and the settling time is 30 minutes. The supernatant in the settling tank ...

Embodiment 2

[0027] Weigh 1500Kg of 5-water crystalline sodium sulfide, 1250Kg of p-dichlorobenzene, 165Kg of catalyst lithium chloride, 5700Kg of solvent N-methylpyrrolidone (wherein 1200Kg is used for dissolving p-dichlorobenzene, and 4500Kg is used for dehydration), and polymerize in the reactor reaction. The pre-polymerization temperature is 223±2°C, and the time is 60 minutes; the polymerization temperature is 262±2°C, and the time is 180 minutes. After the polymerization reaction is completed, the temperature of the mixed slurry is cooled to 80° C., and filtered with a continuous centrifuge to obtain filter cake and by-product slurry. Wash the filter cake with 7500Kg deionized water to obtain PPS wet material and washing water, and dry the PPS wet material in a dryer to obtain the finished PPS product. The washing water and the above-mentioned filtrate were mixed, and then settled in the settling tank, and the settling time was 45 minutes. The supernatant in the settling tank is fi...

Embodiment 3

[0029]Take by weighing 1350Kg of crystalline sodium sulfide pentahydrate, 1230Kg of p-dichlorobenzene, 140Kg of catalyst lithium chloride, 5500Kg of solvent N-methylpyrrolidone (wherein 1000Kg is used for dissolving p-dichlorobenzene, and 4500Kg is used for dehydration), polymerized in the reactor reaction. The pre-polymerization temperature is 225±2°C, and the time is 45 minutes; the polymerization temperature is 265±2°C, and the time is 150 minutes. After the polymerization reaction, the temperature of the mixed slurry was cooled to 85° C., and filtered with a continuous centrifuge to obtain filter cake and by-product slurry. Wash the filter cake with 7500Kg deionized water to obtain PPS wet material and washing water, and dry the PPS wet material in a dryer to obtain the finished PPS product. The washing water and the above-mentioned filtrate were mixed, and then settled in the settling tank, and the settling time was 60 minutes. The supernatant in the settling tank is fi...

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Abstract

Belonging to the field of polymer engineering, the invention in particular relates to a recovery method of by-product sodium chloride in the production process of polyphenylene sulfide (PPS). The method includes the steps of: filtering the mixed slurry obtained at the end of polymerization reaction to obtain a filter cake and a by-product slurry, washing the filter cake with deionized water to obtain washing liquid and a PPS wet material, mixing the washing liquid and the by-product slurry, then carrying out filtering, acidification, aeration, filtration, neutralization, dehydration and refiltering, thus obtaining the byproduct sodium chloride. The sodium chloride recovered by the method provided by the invention has purity of not less than 99.55wt%, and a low molecular polymer content of less than or equal to 0.3wt%, thus meeting the quality requirements of industrial salt. Therefore, no waste salt is generated in the production process of PPS.

Description

technical field [0001] The invention belongs to the field of polymer engineering, in particular to a recovery method for by-product sodium chloride in the production process of polyphenylene sulfide. Background technique [0002] PPS is a polymer compound with good heat resistance, chemical corrosion resistance and flame retardancy. It can be widely used in special fields such as electronic appliances, automobile manufacturing, food machinery, petrochemical, military and other industries. It is known as Following polycarbonate (PC), polyoxymethylene (POM), polyester (PET), nylon (PA) and polyphenylene oxide (PPO), it is the sixth largest general-purpose engineering plastic and one of the eight major aerospace materials. [0003] The industrial production of PPS mainly adopts the sodium sulfide method. The sodium sulfide method is based on p-dichlorobenzene and crystalline sodium sulfide as synthetic raw materials, with N-methylpyrrolidone (NMP) as the solvent, and under the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C319/28
CPCC01D3/04C01D3/14C01P2006/80
Inventor 杨永彬杨虎刘建容帅炳飞
Owner SICHUAN UNIVERSITY OF SCIENCE AND ENGINEERING
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