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Process for refining caprolactam

A technology of caprolactam and crude caprolactam, which is applied in the field of caprolactam refining technology, can solve the problems of insufficient utilization of ion exchange resin exchange capacity, increased energy consumption in the refining process, and shortened resin regeneration cycle, so as to save costs and resources, and reduce regeneration Frequency, the effect of avoiding waste water

Inactive Publication Date: 2015-11-11
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] Chinese patent CN102728415 discloses a method for regeneration of ion exchange resin for refining caprolactam aqueous solution. By combining methanol regeneration with traditional acid-base regeneration, a large amount of nitric acid and caustic soda can be saved, and waste water generated during the regeneration process can be greatly reduced. Production The cost is low, but this method does not solve the problem that the exchange capacity of the ion exchange resin cannot be fully utilized and the resin operation cycle is short
Chinese patent CN104098495 discloses a method for improving the refining process of caprolactam. The crude caprolactam solution obtained after the amide oil containing caprolactam is causticized, extracted, hydrogenated, concentrated and distilled is refined by ion exchange adsorption technology, but after The caprolactam solution obtained after ion exchange still contains a small amount of water, and subsequent concentrated distillation is required to obtain the finished caprolactam, which increases the energy consumption of the refining process
The continuous moving bed chromatography resin device and the continuous moving bed ion exchange device realize the synchronization of resin removal and resin regeneration, but this also greatly shortens the regeneration cycle of the resin, which is not conducive to industrial operation

Method used

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  • Process for refining caprolactam
  • Process for refining caprolactam
  • Process for refining caprolactam

Examples

Experimental program
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Effect test

Embodiment 1

[0040] The extracted caprolactam aqueous solution is subjected to a hydrogenation operation under the action of a Raney nickel catalyst to remove unsaturated by-products in the caprolactam. The temperature of hydrogenation reaction is 75°C, H 2 The pressure is 700kPa, the reaction time is 30min, and the catalyst concentration is about 0.05mg Raney nickel per liter.

[0041] The caprolactam aqueous solution after hydrogenation is cooled to 45°C, pumped countercurrently into the ion exchange adsorption device, wherein the ion exchange device takes the pretreated wet cationic resin and wet anion resin according to the ratio of 1:2, and adopts anion- Yang-yin (volume ratio 1:1:1) is loaded in series. The temperature of ion exchange adsorption is controlled to be 45°C, and the residence time is 45min. Measure the conductivity, absorbance value at 290nm, volatile alkali content and potassium permanganate absorbance value of the discharge liquid. When the extinction value at 290nm...

Embodiment 2

[0043] Repeat the method described in Example 1, the difference is: the temperature of hydrogenation reaction is 90 DEG C, H 2 The pressure is 700kPa, the reaction time is 60min, and the catalyst concentration is about 0.15mg Raney nickel per liter. The results of various quality indexes of caprolactam after hydrogenation and ion exchange are shown in Table 2, and the operating cycle and dynamic adsorption capacity are shown in Table 3.

Embodiment 3

[0045] Repeat the method described in Example 1, the difference is: the temperature of hydrogenation reaction is 105 DEG C, H 2 The pressure is 700kPa, the reaction time is 90min, and the catalyst concentration is about 0.10mg Raney nickel per liter. The results of various quality indexes of caprolactam after hydrogenation and ion exchange are shown in Table 2, and the operating cycle and dynamic adsorption capacity are shown in Table 3.

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Abstract

The invention discloses a process for refining caprolactam. The process comprises the following steps: performing a hydrogenation reaction on a coarse caprolactam aqueous solution which is obtain after an extraction process; then, adsorbing by ion exchange; and further concentrating and distilling to prepare high-purity caprolactam. The process breaks through the convention of sequentially adsorbing and hydrogenating in the prior art, the extracted caprolactam aqueous solution is refined by adopting a process of sequentially hydrogenating and adsorbing by ion exchange, so that the content of impurities and inorganic salt which exist in coarse caprolactam and influence the product quality can be effectively reduced, and the coarse caprolactam can be purified. According to the process, the use cycle of ion exchange resin is prolonged, the number of regeneration times is reduced, massive wastewater generated by ion exchange resin regeneration is avoided, cost and resources can be reduced on the premise of improving the product quality, and pollution can be reduced.

Description

technical field [0001] The invention relates to a refining process of caprolactam, specifically, the crude caprolactam solution after the amide oil containing caprolactam is neutralized with ammonia water, extracted with benzene, and stripped with water is subjected to hydrogenation reaction, and then filled with anion-cation exchange resin A refining method for ion-exchange adsorption. Background technique [0002] Caprolactam is an important organic chemical raw material. It is mainly used as a raw material for the production of polyamide 6 engineering plastics and polyamide 6 fibers. It can also be used for the production of antiplatelet drugs such as 6-aminocaproic acid and laurocaprolactone. It is very useful. widely. Volume 3 of the second edition of "Encyclopedia of Organic Chemical Materials" introduces the production methods and industrial status of caprolactam, mainly including cyclohexane photonitrosation method, cyclohexanone-hydroxylamine method, toluene method...

Claims

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Application Information

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IPC IPC(8): C07D201/16C07D223/10
CPCC07D201/16C07D223/10
Inventor 吴剑孙伟杰杜思思
Owner XIANGTAN UNIV
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