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A kind of purification method and device of caprolactam

A caprolactam and purification method technology, applied in the separation/purification of lactam, chemical instruments and methods, organic chemistry, etc., can solve the problems of fragility, low washing efficiency, large investment, etc., and achieve the effect of convenient operation and simple structure

Active Publication Date: 2016-10-26
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Using the existing solid-liquid separation methods such as centrifugal filtration, pressure filtration, vacuum suction filtration, etc., not only the process is cumbersome, the investment is large, and the washing efficiency is low, but also the caprolactam in the mother liquor is easy to precipitate crystal scars on the wall of the filter equipment during operation. cause operational difficulties
Especially caprolactam, due to its inherent characteristics, the resulting crystals are sheet-like structures with poor strength and are easily broken, which makes solid-liquid separation and washing and filtration more difficult, thus limiting the wide application of crystallization.

Method used

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  • A kind of purification method and device of caprolactam
  • A kind of purification method and device of caprolactam
  • A kind of purification method and device of caprolactam

Examples

Experimental program
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Effect test

specific Embodiment approach

[0038] A method for purifying ε-caprolactam, comprising:

[0039] (1) Crystallizing crude ε-caprolactam containing impurities in the presence of solvent A to obtain a crystal slurry containing solvent A;

[0040] (2) washing the crystal slurry obtained in step (1) with solvent B to obtain the washed crystal slurry and mother liquor containing solvent B;

[0041] (3) Separate the solvent B in the magma after washing in step (2) to obtain ε-caprolactam.

[0042] Preferably, the step (3) includes:

[0043] (4) heating and dissolving the washed crystal slurry obtained in step (2) to obtain ε-caprolactam solution;

[0044] (5) Distilling off the solvent B in the ε-caprolactam solution in step (4) to obtain ε-caprolactam.

[0045] Preferably, the solvent B recovered by distillation in step (4) is returned to step (2) for reuse.

[0046] In the method provided by the present invention, step (1) is to continuously feed the crude caprolactam containing impurities and solvent A into...

Embodiment 1

[0096] Take 600 grams of crude caprolactam and 600 grams of isopropyl ether and add them to a 2L glass kettle with stirring and a jacket. Heat hot water in the jacket to 70 degrees until the caprolactam is completely dissolved. Under stirring, adjust the jacket The temperature of the water inside is gradually lowered to 20° C. to obtain a crystal slurry of caprolactam.

[0097] The above-mentioned magma is transferred into a washing column with a jacket of 50 mm in height and 800 mm in length, and 1140 grams of normal temperature n-heptane are continuously fed from the bottom for countercurrent washing, and the mother liquor is drawn out from the top.

[0098] The concentration of the crystal slurry after washing is about 50%, and it is transferred to a distillation kettle and heated to 85°C for dissolution.

[0099] 456g of solvent was distilled off under normal pressure, and then the remaining solvent was distilled off under reduced pressure to 1.3kPa, and 558g of purified c...

Embodiment 2

[0101] By the same method as in Example 1, the difference is that 1092 g of isopropyl ether solution in which 4.2% caprolactam is dissolved is used as a solvent for backwashing. 592 grams of purified caprolactam were obtained from the still of the distillation tower. A small amount of purified caprolactam was taken for chromatographic analysis. The purity of caprolactam was 99.98%. Cyclohexanone oxime and swahydrophenazine were not detected. N-methyltetrahydrobenzimidazole: 4 μg / g. The PM value is 120s, the V.B value is 0.34mmol / kg, and the E value is 0.150.

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Abstract

The invention provides a caprolactam purification method and device, and the method includes crystallization, countercurrent washing, solvent evaporation and other processes, is in no need of solid-liquid separation, can produce high-quality epsilon-caprolactam refining products, and is especially suitable for refinement of crude epsilon-caprolactam obtained by gas phase rearrangement. The caprolactam purification device includes a crystallizer, a countercurrent scrubber, a heater and distillation equipment which are sequentially communicated, has the advantages of simple structure and capability of continuous operation, and is applicable to the purification process of crude caprolactam.

Description

technical field [0001] The present invention relates to a preparation method and device for ε-caprolactam. More specifically, it relates to a purification method and purification apparatus for crude ε-caprolactam containing impurities. Background technique [0002] ε-caprolactam (hereinafter referred to as caprolactam) is an important monomer of synthetic fibers and synthetic resins, mainly used in the manufacture of polyamide fibers (nylon 6), resins and films. The known production methods of caprolactam include cyclohexanone oxime liquid-phase Beckmann rearrangement method using oleum as catalyst, cyclohexanone oxime gas-phase Beckmann rearrangement method using solid zeolite as catalyst, and methods such as depolymerization of waste polymers. . The caprolactam prepared by these methods inevitably contains a large variety of organic impurities, which seriously affect the quality of caprolactam, and therefore must be purified before application. Known caprolactam purific...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D223/10C07D201/16
CPCC07D201/16C07D223/10
Inventor 杨克勇范瑛琦王皓江雨生张树忠宗保宁
Owner CHINA PETROLEUM & CHEM CORP
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