Method for recycling paradichlorobenzene in polyphenylene sulphide production mother liquor

A technology of p-dichlorobenzene and polyphenylene sulfide, which is applied in the field of p-dichlorobenzene recovery, can solve the problems of inability to recycle dichlorobenzene, increase the cost of use, and easily pollute the environment, so as to improve biodegradability and reduce production The effect of using cost and reducing pollution

Inactive Publication Date: 2015-11-11
ZHANGJIAGANG XINSHENG NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, after the production of polyphenylene sulfide by the sodium sulfide method, it is impossible to recycle the p-dichlorobenzene remaining in the mother liquor of polyphenylene sulfide production, which not only causes waste of resource

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] The recovery method of p-dichlorobenzene in polyphenylene sulfide production mother liquor, comprises the following steps:

[0020] (1) First filter the mother liquor of polyphenylene sulfide to remove the oligomers in the mixed liquor;

[0021] (2) Distill the filtered polyphenylene sulfide production mother liquor at a temperature of 150°C to obtain NMP solvent and p-dichlorobenzene wastewater;

[0022] (3) Next, the p-dichlorobenzene wastewater was settled for 6 hours at a temperature of 0°C;

[0023] (4) Then centrifuge the settled p-dichlorobenzene wastewater to obtain crude p-dichlorobenzene crystals;

[0024] (5) Then melt the crude p-dichlorobenzene crystals at a temperature of 50°C to form liquid crude p-dichlorobenzene;

[0025] (6) Then filter the liquid crude p-dichlorobenzene to remove the insoluble matter in the liquid crude p-dichlorobenzene;

[0026] (7) Next, the liquid crude p-dichlorobenzene from which insoluble matter has been removed is settled f...

Embodiment 2

[0028] The recovery method of p-dichlorobenzene in polyphenylene sulfide production mother liquor, comprises the following steps:

[0029] (1) First filter the mother liquor of polyphenylene sulfide to remove the oligomers in the mixed liquor;

[0030] (2) Distill the filtered polyphenylene sulfide production mother liquor at a temperature of 160°C to obtain NMP solvent and p-dichlorobenzene wastewater;

[0031] (3) Next, settle the p-dichlorobenzene wastewater at a temperature of 10°C for 12 hours;

[0032] (4) Then centrifuge the settled p-dichlorobenzene wastewater to obtain crude p-dichlorobenzene crystals;

[0033] (5) Then melt the crude p-dichlorobenzene crystals at a temperature of 55°C to form liquid crude p-dichlorobenzene;

[0034] (6) Then filter the liquid crude p-dichlorobenzene to remove the insoluble matter in the liquid crude p-dichlorobenzene;

[0035] (7) Next, the liquid crude p-dichlorobenzene from which the insoluble matter was removed was settled for ...

Embodiment 3

[0037] The recovery method of p-dichlorobenzene in polyphenylene sulfide production mother liquor, comprises the following steps:

[0038] (1) First filter the mother liquor of polyphenylene sulfide to remove the oligomers in the mixed liquor;

[0039] (2) Distill the filtered polyphenylene sulfide production mother liquor at a temperature of 200°C to obtain NMP solvent and p-dichlorobenzene wastewater;

[0040] (3) Next, settle the p-dichlorobenzene wastewater at a temperature of 30°C for 18 hours;

[0041] (4) Then centrifuge the settled p-dichlorobenzene wastewater to obtain crude p-dichlorobenzene crystals;

[0042] (5) Then melt the crude p-dichlorobenzene crystals at a temperature of 80°C to form liquid crude p-dichlorobenzene;

[0043] (6) Then filter the liquid crude p-dichlorobenzene to remove the insoluble matter in the liquid crude p-dichlorobenzene;

[0044] (7) Next, the liquid crude p-dichlorobenzene from which insoluble matter has been removed is settled for ...

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PUM

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Abstract

The invention discloses a method for recycling paradichlorobenzene in polyphenylene sulphide production mother liquor. The method comprises the following steps: (1) firstly filtering the polyphenylene sulphide production mother liquor and removing impurities; (2) distilling the filtered polyphenylene sulphide production mother liquor at the temperature of 150-200 DEG C, so that an NMP solvent and paradichlorobenzene waste water are obtained; (3) then settling the paradichlorobenzene waste water for 6-18 hours at the temperature of 0-30 DEG C; (4) centrifuging and separating settled paradichlorobenzene to obtain crude paradichlorobenzene crystals; (5) melting the crude paradichlorobenzene crystals at the temperature of 50-80 DEG C, so that liquid-state crude paradichlorobenzene is obtained; (6) filtering liquid-state crude paradichlorobenzene, and removing insoluble substances in liquid-state crude paradichlorobenzene; and (7) settling liquid-state paradichlorobenzene with the insoluble substances removed for 1-2 hours at the temperature of 0-20 DEG C, so that refined paradichlorobenzene crystals are obtained. The method disclosed by the invention has the advantage that paradichlorobenzene in the polyphenylene sulphide production mother liquor can be recycled.

Description

technical field [0001] The invention relates to a method for recovering p-dichlorobenzene in the mother liquor of polyphenylene sulfide production. Background technique [0002] The sodium sulfide method is mostly used in the production of polyphenylene sulfide at home and abroad. The raw materials used in the sodium sulfide method are p-dichlorobenzene and sodium sulfide, and the solvent used is N-methylpyrrolidone (NMP for short). The raw materials and solvent form polyphenylene sulfide. In the ether reaction mother liquor, the molar amount of p-dichlorobenzene in the raw material ratio generally needs to be 1-10% more than that of sodium sulfide. In the process of producing polyphenylene sulfide by the sodium sulfide method, after the polyphenylene sulfide in the polyphenylene sulfide reaction mother liquor completes the polycondensation reaction with sodium sulfide and p-dichlorobenzene, the polyphenylene sulfide in the polyphenylene sulfide reaction mother liquor is als...

Claims

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Application Information

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IPC IPC(8): C07C25/08C07C17/38
Inventor 唐峰栗鹏伟
Owner ZHANGJIAGANG XINSHENG NEW MATERIAL
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