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Short-process continuous preparation system and method of laurolactam

A laurolactam and preparation system technology, which is applied in the field of continuous preparation system of laurolactam, can solve the problems of large mass transfer resistance, affecting the purity of cyclododecanone oxime, reducing production efficiency, etc., and achieve high selectivity , shorten the production time, reduce the effect of equipment footprint

Active Publication Date: 2021-12-10
BEIJING UNIV OF CHEM TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in actual production, since the oximation reaction occurs between the water phase and the oil phase, the mixing effect of the two phases is poor, and the mass transfer resistance is large, so that the hydroxylamine in the water phase cannot be consumed quickly, and a large amount of free ammonia exists in the system.
Free ammonia can form a by-product cyclododecanoimine with cyclododecanone, which affects the purity of cyclododecanone oxime
The current process uses hydroxylamine salt to drop the feed to reduce the presence of free ammonia to inhibit the formation of by-products, but obviously it will greatly reduce production efficiency

Method used

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  • Short-process continuous preparation system and method of laurolactam
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  • Short-process continuous preparation system and method of laurolactam

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0110] The system and method of the present invention are used to produce laurolactam, n-dodecane is selected as the rearrangement reaction solvent, the refining section adopts a cooling crystallization method, and laurolactam crystals are obtained after filtration, and the filtrate is refluxed. During operation, pre-add 20L cyclododecanone as a circulating fluid, and feed the system after the system runs stably. The molar flow rate of hydroxylamine in the freshly fed hydroxylamine solution and the molar flow rate of the freshly fed cyclododecanone conform to the chemical reaction of oximation. Metering ratio, the feed flow rate is 1L / min, in the oximation reaction phase separator, the molar flow rate of hydroxylamine in the feed hydroxylamine solution: the molar flow rate R of cyclododecanone in the feed oil phase 1 =1:10; temperature T in the oximation reaction phase separator 1 Controlled at 95°C, the temperature T in the rearrangement reactor 2 Control at 140°C; the circu...

Embodiment 2～20

[0111] Examples 2-20: The process flow and stable running time are the same as those in Example 1. Some key process parameters and test results are shown in Table 1. The meanings and units represented by the letters in the header are consistent with those in Example 1.

[0112] Table 1 Embodiment 2~20 process conditions and experimental results

[0113]

[0114]

[0115] In all examples, examples 1 to 9 are within the range of process parameters advocated by the present invention, and can be drawn from the results of the examples, the purity of the crude product can reach 99%, and the high-quality single product with a purity of more than 99.9% can be obtained after refining. body, the conversion rate of hydroxylamine can also be controlled above 99.8%.

[0116] In all examples, some process operating parameters of embodiments 10 to 20 are outside the range of process parameters advocated by the present invention, and it can be drawn from the results of the examples that...

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Abstract

The invention provides a continuous preparation system and method of laurolactam. A supergravity reactor is coupled with a centrifugal phase separation process to strengthen an oximation reaction between oil and water phases, and the supergravity reactor is coupled with rectification, neutralization and phase separation processes to carry out a rearrangement reaction. With the system and method adopted,the problems of low oximation process selectivity, slow oximation and separation processes, difficult rearrangement reaction heat transfer, many side reactions in the rearrangement process and the like can be solved, a high-purity and high-selectivity laurolactam product can be obtained. The system and method have the advantages of significantly shortened production time and reduced occupied area of devices compared with the prior art.

Description

technical field [0001] The invention relates to a continuous preparation system and method of laurolactam, belonging to the fields of chemical technology and chemical engineering. Background technique [0002] Nylon 12 is commonly known as polylaurolactam. It is the product with the lowest relative density and water absorption in nylon. It has the characteristics of good dimensional stability, strong low temperature resistance, and easy processing and molding. It is widely used in automobile pipelines and industrial special pipes. Roads, cable sheaths, 3D printing consumables, etc. China's annual demand for nylon 12 is more than 20,000 tons, but its production technology is still monopolized by overseas manufacturers. The key to producing high-quality nylon 12 is to obtain high-purity polymerized monomer laurolactam. Cyclododecanone oximation to obtain cyclododecanone oxime and then Beckmann rearrangement reaction to laurolactam has the advantages of low cost, easy availabi...

Claims

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Application Information

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IPC IPC(8): B01J19/18B01J14/00B01D3/00B01D17/038C07D225/02
CPCB01J14/00B01J19/0066B01J19/1862B01D17/0217B01D3/009C07D225/02
Inventor 张亮亮初广文陈建峰毛伟孙宝昌邹海魁罗勇
Owner BEIJING UNIV OF CHEM TECH