Method for purifying N-methyl pyrrolidone

A technology of methyl pyrrolidone and poly(p-phenylene terephthalamide), which is applied in the field of solvent recovery and purification, can solve the problems of high cost, complicated recovery process, unfavorable large-scale production and use, etc., so as to improve work efficiency and simplify the process. Process, the effect of good application prospects

Inactive Publication Date: 2013-03-27
DONGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method has high input costs and complicated process operation, making it difficult to popularize and apply
[0005] However, these methods also have the disadvantages of low quality solvent recovery, high water content, inability to recover additives, complex recovery process, and high cost, which are not conducive to large-scale production and use.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Wash the poly-p-phenylene terephthalamide polymer obtained after the polycondensation reaction with 100-400 parts of deionized water repeatedly to obtain a lotion containing N-methylpyrrolidone (NMP); add hydrogen to the lotion Sodium oxide is neutralized to adjust the pH value of the solution to 6-7; the lotion is distilled and dehydrated to separate and remove the pyridine in the lotion; 200 grams of neutral aqueous solution containing 65% NMP and 7.5% inorganic salts, and 600 g of chloroform Mix well in a stainless steel funnel and let stand to separate. 140 g of NMP solution containing 9.5% of the aqueous layer were obtained. The water layer was then fully mixed with 380 g of chloroform, and allowed to stand to separate layers. Then get 90g water layer, which contains NMP 0.7g, CaCl 2 and other inorganic salts 13g. A total of 127.4 g of NMP was obtained by two extractions, with a yield of 98%. Add 20ml of TDI solution to the NMP solution under stirring, and a wh...

Embodiment 2

[0025] Wash the poly-p-phenylene terephthalamide polymer obtained after the polycondensation reaction with 100-400 parts of deionized water repeatedly to obtain a lotion containing N-methylpyrrolidone (NMP); add carbonic acid to the lotion The sodium is neutralized to adjust the pH value of the solution to 6-7; the lotion is distilled and dehydrated, and the pyridine in the lotion is separated and removed; 200g of a neutral aqueous solution containing 35% NMP and 3.8% of inorganic salts is mixed with 500g of chloroform in a stainless steel Mix well in the funnel and let stand to separate layers. 80 g of NMP solution containing 14.5% of the aqueous layer were obtained. The water layer was then fully mixed with 380 g of chloroform, and allowed to stand to separate layers. The water layer weighs 148 grams, wherein the NMP content is 0.92 g, CaCl 2 7.2 grams of other inorganic salts. A total of 69.51 g of NMP was obtained through two extractions, with a yield of 99.3%. Add 10m...

Embodiment 3

[0027] Wash the poly-p-phenylene terephthalamide polymer obtained after the polycondensation reaction with 100-400 parts of deionized water repeatedly to obtain a lotion containing N-methylpyrrolidone (NMP); add hydrogen to the lotion Sodium oxide is neutralized to adjust the pH value of the solution to 6-7; the lotion is distilled and dehydrated, and the pyridine in the lotion is separated and removed; 200g of neutral aqueous solution containing 50% NMP and 5.8% inorganic salt is mixed with 550g chloroform in Fully mix in a stainless steel funnel, and let stand to separate layers. 110 g of NMP solution with 11% aqueous layer were obtained. The water layer was then fully mixed with 380 g of chloroform, and allowed to stand to separate layers. Another 110g aqueous layer was obtained, containing 1.1g of NMP, CaCl 2 Etc. Inorganic salt 9.4g. A total of 99 g of NMP was obtained through two extractions, with a yield of 99%. Add 15ml of TDI solution to the NMP solution under sti...

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Abstract

The invention relates to a method for purifying N-methyl pyrrolidone. The method comprises the steps of (1) washing poly-p-phenylene terephthamide polymers obtained after the polycondensation through deionized water repeatedly to obtain washing liquor containing the N-methyl pyrrolidone (NMP), adding antalkali into the washing liquor to perform neutralizing treatment, and regulating PH of the solution to 6-7; (2) performing extraction separation on the washing liquor to obtain solution with an NMP-extraction agent system on the lower layer and a water-inorganic salt system on the upper layer, and performing secondary extraction on the water-inorganic salt system on the upper layer; and (3) adding an organic solution with an isocyanic acid functional group into a crude product of the NMP, and performing filtering and distillation to obtain the high-purity NMP. By means of the method, the purity of the finally-obtained NMP solvent is remarkably improved, processing procedures are simplified, accordingly, working efficiency is improved, and operability is strong. Furthermore, the purity of the NMP solvent obtained by means of purifying is higher than 99.8%, and the water content of the NMP solvent is smaller than 0.01%.

Description

technical field [0001] The invention belongs to the field of solvent recovery and purification, in particular to a method for purifying N-methylpyrrolidone. Background technique [0002] As we all know, poly-p-phenylene terephthalamide (PPTA) is a mixture of p-phenylenediamine and terephthaloyl chloride in N-methylpyrrolidone (NMP) and calcium chloride (CaCl 2 ) solution system through low temperature solution polycondensation reaction. After the reaction is finished, the water content of the recovered NMP is still high and cannot be recycled again. Therefore, in the current environment where energy conservation and environmental protection are advocated, how to highly purify crude NMP products and remove water has become an important topic for universities and research institutions. [0003] Patent CN1810851 adopts a recycling method for the polymerization solvent, first neutralizes the waste liquid, then filters to obtain the filtrate, and then performs dehydration, desa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D207/267
Inventor 余木火杜凌栋张蕊滕翠青孔海娟姜正飞陆川王宁钟鸿鹏
Owner DONGHUA UNIV
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