Method for recycling lithium salt and solvent in preparation of polyphenylene sulfide

A technology of polyphenylene sulfide and lithium salt, applied in the field of lithium salt and solvent recycling, can solve the problems of affecting recycling, high energy consumption, low efficiency, etc.

Active Publication Date: 2014-08-06
SHANDONG MINGHUA NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The crosslinking reaction efficiency of this method is low, and at the same time, the decomposition loss of the solvent NMP is serious during the heating process, and the recovery rate is about 90%, and it also contains organic sulfur compounds, which affects the subsequent recycling.
[0009] Because in the recovery method to lithium chloride and solvent including above-mentioned bibliography, all will consume other chemical substances, and flow process is long, efficiency is low, energy consumption is high, and the quality of recovery component is also not ideal enough, needs further research Improve

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Using sodium sulfide and p-dichlorobenzene (1 mol each) as raw materials, under the conditions of NMP reaction medium solvent (300 ml) and lithium chloride (0.6 mol) as catalysts, high-temperature polycondensation was carried out according to the methods reported so far Reaction, after preparing the polyphenylene sulfide resin product, the temperature of the reaction system was lowered to 80°C-120°C for heat preservation and filtration, and 230.3g of polyphenylene sulfide resin product and 328g of polycondensation filtrate solvent were obtained by separation.

[0028] Add the separated polycondensation resin polyphenylene sulfide into the washing tank, add 100ml of NMP-water mixed solvent containing 10 (w)% of water to disperse, and heat to 200~250 under nitrogen (or other inert gas, the same below) environment Stir at ℃ for 0.5h, cool to 80~120℃ and filter with heat preservation to obtain 108g of solvent washing filtrate.

[0029] A total of 436g of the polycondensatio...

Embodiment 2

[0032] Using sodium sulfide and p-dichlorobenzene (1 mol each) as raw materials, under the conditions of NMP reaction medium solvent (300 ml) and lithium chloride (0.8 mol) as catalysts, high-temperature polycondensation was carried out according to the methods reported so far Reaction, after preparing the polyphenylene sulfide resin product, the temperature of the reaction system was lowered to 80°C-120°C for heat preservation and filtration, and 234g of polyphenylene sulfide resin product and 333g of polycondensation filtrate solvent were obtained by separation.

[0033] Add the polycondensation resin polyphenylene sulfide obtained by separation into the washing tank, add 100ml of NMP-water mixed solvent containing 20 (w)% of water to disperse, and heat to 200~250 under nitrogen (or other inert gas, the same below) environment Stir at ℃ for 0.5h, cool to 80~120℃ and filter with heat preservation to obtain 112g of solvent washing filtrate.

[0034] The polycondensation filtra...

Embodiment 3

[0037] Basic process is the same as embodiment 1. The difference is that the remaining liquid after the separation of oligomers is distilled at 100~101.3kPa and 80~160°C to precipitate the sodium chloride in it, and the white sodium chloride crystal grains are removed by filtration at 80~120°C. g. In the last step, 290ml of NMP was evaporated at 20~30kPa and 120~185°C, so that the concentration of lithium chloride in the concentrated solution reached 23.2%. g, purity 98%, precipitation rate 60.07%.

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Abstract

The invention discloses a method for recycling lithium salt and a solvent in preparation of polyphenylene sulfide. The method comprises the following operation processes: 1', washing a polyphenylene sulfide product by use of an N-methyl pyrrolidone solution of which the percentage by weight of water is not larger than 50% at the temperature of 150 to 250 DEG C in an inert gas environment, and combining the washing solution with a reaction medium solution; 2', transforming sodium sulfide into sodium chloride under the condition that the pH value of the combined solution is regulated to 6.5-7.0 in the inert gas environment; 3', adding water into the solution transformed in the step 2 so that the low-molecular polyphenylene sulfide is precipitated and then separated; and 4', respectively separating and recycling the sodium chloride, the N-methyl pyrrolidone and the lithium chloride from the separated solution under the inert gas environment. According to the method, the solvents need not to be evaporated out completely, so the energy consumption is reduced greatly; the method can be performed in various intermittent or continuous ways and convenient and easy to implement, degradation caused because the solvent is at high temperature for a long time is avoided, so the recycle rate of the solvent is high, and the recycling quality is good; a separated and recycled polyphenylene sulfide oligomer is utilizable, the purity of the recycled lithium chloride is not lower than 98%, and the quality of the recycled sodium chloride is excellent.

Description

technical field [0001] The invention relates to a lithium salt and a solvent recycling method in the preparation of p-polyphenylene sulfide. Background technique [0002] Polyphenylene sulfide is a special engineering material with excellent performance. It has outstanding and excellent performance in terms of electrical insulation, chemical corrosion resistance, and dimensional stability. It can be processed by extrusion molding, blow molding, and molding. Made into fibers, films, and other products, it is widely used in machinery, aerospace, electronics, chemicals, and other industrial fields, and has very broad application prospects. [0003] The industrial preparation of polyphenylene sulfide resin is currently obtained by polycondensation of metal sulfide / hydrosulfide and dihalogenated benzene in polar organic solvent N-methylpyrrolidone (NMP). Due to the need to use a large amount of organic solvents and expensive lithium salt catalysts in the production process of po...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G75/02C08G75/0281
Inventor 李晶晶李华杨琴罗芩曾刚
Owner SHANDONG MINGHUA NEW MATERIAL CO LTD
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