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Preparation method for caprolactam

A technology of caprolactam and cyclohexanone, applied in the field of preparation of caprolactam, can solve the problems of low caprolactam yield, high ammonium sulfate by-product, long process flow, etc. Yield effect

Inactive Publication Date: 2016-08-10
HUBEI JINXIANGNING CHEM ENG TECHENOLOGY CO LTD +1
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  • Abstract
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Benefits of technology

The technical effect of this patented technology improves how well it makes hexadecylamine with high purity. It eliminates any extra steps like filtrating or rinsing out certain substances from crude lactic acid ammonia salt beforehand during its manufacture. This results in more efficient use of resources for producing these compounds while maintaining their quality level.

Problems solved by technology

The patent text discusses the production of caprolactam, which is used to make nylon 6. The current methods for producing caprolactam involve several steps, including the preparation of cyclohexanone oxime and the Beckmann rearrangement reaction. However, these methods have limitations such as low conversion rate, the need for additional refining steps, and increased production costs. Therefore, the technical problems addressed in this patent are improving the yield of caprolactam, simplifying the process, and reducing energy consumption.

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  • Preparation method for caprolactam

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preparation example Construction

[0017] The preparation method of caprolactam provided by the invention comprises the following steps:

[0018] (1) In the presence of an oximation catalyst and without any organic solvent, cyclohexanone, ammonia and hydrogen peroxide are carried out in an aqueous solution for ammoximation reaction, and the temperature of the ammoximation reaction is 50 -200°C, a solution containing cyclohexanone oxime was obtained;

[0019] (2) Extracting the solution containing cyclohexanone oxime obtained in step (1) with an inert organic solvent to obtain an extract phase containing cyclohexanone oxime and a raffinate phase containing an oximation catalyst and water;

[0020] (3) performing a Beckmann rearrangement reaction on the extract phase with oleum, and then neutralizing the product of the Beckmann rearrangement reaction with ammonia.

[0021] The present invention has no special limitation on the amount of water used in the ammoximation reaction system, and it can be reasonably add...

Embodiment 1

[0043] This example is used to illustrate the preparation method of caprolactam provided by the present invention.

[0044] In the ammoximation reactor, load 100t oximation catalyst aqueous solution, wherein, the content of oximation catalyst is 3% by weight, and then ammonia gas, cyclohexanone, hydrogen peroxide (concentration is 27.5% by weight) are respectively mixed with 1.94t / h , 10.9t / h and 15.2t / h flows into the ammoximation reactor for the ammoximation reaction, the controlled reaction temperature is 90-100°C, the reaction pressure is 300kPa (absolute pressure), and the material is The residence time in the reactor was 70 minutes, and an aqueous solution of cyclohexanone oxime was obtained. Hexanaphthene enters the cyclohexanone oxime aqueous solution (relative to the cyclohexanone of 1mol, the consumption of hexamethylene is 3mol) that the flow of 33t / h and the flow from the ammoximation reactor are 88t / h fully mixed and enters cyclohexane. liquid separator. The hea...

Embodiment 2

[0046] This example is used to illustrate the preparation method of caprolactam provided by the present invention.

[0047] In the ammoximation reactor, 100t aqueous solution of oximation catalyst is charged, wherein the content of oximation catalyst is 3% by weight, then ammonia, cyclohexanone, hydrogen peroxide (concentration is 27.5% by weight) are respectively mixed with 5.19t / h , 27.22t / h and 38.46t / h flows into the ammoximation reactor for the ammoximation reaction, the controlled reaction temperature is 80-85°C, the reaction pressure is 250kPa (absolute pressure), and the material is The residence time in the reactor was 80 minutes, and an aqueous solution of cyclohexanone oxime was obtained. Hexanaphthene enters the cyclohexanone oxime aqueous solution (relative to the cyclohexanone of 1mol, the consumption of hexamethylene is 3mol) that the flow of 82t / h comes from the flow of ammoximation reactor is 136t / h fully mixes and enters cyclohexane liquid separator. The he...

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Abstract

The invention provides a preparation method of caprolactam, which includes the following steps: (1) in the presence of an oximation catalyst without any organic solvent, cyclohexanone, ammonia and hydrogen peroxide are subjected to an ammoximation reaction in a water solution at 50-200 DEG C to prepare a solution containing cyclohexanone-oxime; (2) extracting the solution containing cyclohexanone-oxime with an inert organic solution to obtain an extract phase containing the cyclohexanone-oxime and a raffinate phase containing the oximation catalyst and water; (3) performing a Beckmann rearrangement reaction to the extract phase and fuming sulfuric acid, and performing a neutralization reaction to the product of the Beckmann rearrangement reaction with ammonia. The method can not only increase the yield of caprolactam but also omits a purifying process of cyclohexanone-oxime, thereby significantly reducing the process and production period. Meanwhile, the inert organic solvent can be recycled by recycling rearrangement reaction heat.

Description

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Claims

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Application Information

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Owner HUBEI JINXIANGNING CHEM ENG TECHENOLOGY CO LTD
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