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Method for recycling DMAC (Dimethyl Acetylamide) from waste spandex stock solution

A technology of waste stock solution and spandex, applied in the field of N recycling, can solve the problems of complex process, increase solvent loss, secondary pollution, etc., and achieve the effect of no pollution in recovery rate, simple process and no loss.

Active Publication Date: 2010-12-22
JIANGSU SHUANGLIANG SPANDEX
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  • Abstract
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Problems solved by technology

However, this method has the following disadvantages: on the one hand, there is a loss of extractant, which causes secondary pollution; on the other hand, the entire separation process is composed of an atmospheric pressure concentration tower and a decompression passivation tower, which is complex, consumes a lot of energy, and has high recovery costs. , and the decompression operation increases the loss of solvent

Method used

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  • Method for recycling DMAC (Dimethyl Acetylamide) from waste spandex stock solution
  • Method for recycling DMAC (Dimethyl Acetylamide) from waste spandex stock solution
  • Method for recycling DMAC (Dimethyl Acetylamide) from waste spandex stock solution

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Embodiment Construction

[0028] see figure 1 with figure 2 , figure 1 It is a flow chart of the water treatment and separation process of spandex waste stock solution of the present invention. figure 2 It is a flow chart of the DMAC recovery process in the spandex waste stock solution of the present invention. Depend on figure 1 with figure 2 As can be seen, the method for reclaiming DMAC from spandex waste stock solution includes the following processes:

[0029] First, prepare the ionic liquid

[0030] Mix methylimidazole and 3-chloropropyl ether evenly at a molar ratio of 1:1, reflux in a water bath at 85-95°C for 20-30 hours under nitrogen protection, and then wash with silicone or ether to remove unconverted reactants , to remove silicone or ether by rotary evaporation. Then add potassium hexafluorophosphate (KPF 6 ), heated to 85-95°C for 15 hours, cooled, washed with deionized water and dried, and finally evaporated at 85°C for 10 hours to remove impurities to obtain an ionic liquid....

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Abstract

The invention relates to a method for recycling DMAC (Dimethyl Acetylamide) from a waste spandex stock solution, comprising the following processes of: dividing a collected waste spandex stock solution into small blocks of 1-10 square centimeters, soaking the small blocks into deionized water, filtering and separating the mixture by a press filter to obtain a solid phase and a liquid phase, renewedly soaking the solid phase into a soaking pool, and repeating the operations many times; making the liquid phase and the ion liquid enter an extraction apparatus according to the mass rate of 1:0.5-3 to carry out mixed extraction, enriching DMAC in the mixed solution to the ion liquid phase to form an extraction phase containing the ion liquid and the DMAC as well as an extraction raffinate containing the deionized water and inorganic matters, making the extraction raffinate enter a rectifying apparatus, separating out the DMAC from the ion liquid phase with a method of decompression and distillation, and circularly recycling the ion liquid. In the invention, the method has the advantages of high recycling ratio of the DMAC and low energy consumption in the recycling process without causing secondary pollution.

Description

(1) Technical field [0001] The invention relates to a method for recovering N,N-dimethylacetamide (DMAC) from spandex waste stock solution. (2) Background technology [0002] N,N-Dimethylacetamide (DMAC) is a strong polar aprotonated solvent, compared with N,N-dimethylformamide (DMF), DMAC has lower toxicity and volatility, better stability High, not easy to change color, widely used in petroleum processing and organic synthesis industry. DMAC has good solubility properties for various resins, especially polyurethane resins and polyimide resins, and can be used as a solvent for heat-resistant fibers, plastic films, coatings, pharmaceuticals, catalysts, etc. [0003] At present, in the spandex production process, most of them use DMAC as the polymerization solvent. In the production process of polyurethane fiber, a large amount of spandex waste stock solution is caused by the sampling and discharge of the viscosity of the polymerization stock solution, the cleaning of the s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C233/05C07C231/24
Inventor 张磊何春远李广忠陈志成
Owner JIANGSU SHUANGLIANG SPANDEX
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