Method for preparing laurolactam through extraction rearrangement reaction of cyclododecanone oxime

Abstract

The invention discloses a method for preparing laurolactam through extraction rearrangement reaction of cyclododecanone oxime, which comprises the steps of (1) adding a cyclododecanone oxime solutionand an acidic catalyst into an extraction kettle in proportion, strongly stirring and mixing in the kettle to extract cyclododecanone oxime from a solvent phase to a catalyst phase, wherein the solution is liquid-liquid biphase in the reaction kettle, and the reaction is carried out in a catalyst phase; (2) removing extraction reaction heat and part of rearrangement reaction heat from the materialin the extraction kettle through an outer circulating pump and an outer circulating cooler, wherein one strand of material is led out from an outlet of the outer circulating pump to serve as feed ofa rearrangement kettle, and the other strand of material is led out from an outlet of the outer circulating cooler to serve as an inlet medium of a heat transfer inner coil of the rearrangement kettle; and (3) mixing the outlet material of the coil pipe in the rearrangement kettle with the outlet material of the outer circulating cooler of the extraction kettle, feeding the mixture into the extraction kettle, and feeding the rearrangement kettle material into a downstream neutralization process. The heat transfer mode is small in temperature difference in the rearrangement kettle, materials can be effectively prevented from being supercooled, and the conversion rate of reaction materials is guaranteed.

Description

Technical field: [0001] The invention relates to a method for preparing laurolactam through extraction and rearrangement of cyclododecanone oxime, especially suitable for the extraction and rearrangement of cyclododecanone oxime solution with solvent in liquid-liquid two-phase under the condition of an acidic catalyst Continuous process for the preparation of laurolactam. Background technique [0002] Lauryl lactam is an important organic chemical raw material, which can be polymerized to obtain nylon 12. As a special nylon product, compared with general-purpose nylon (such as nylon 6), nylon 12 has the advantages of low water absorption, high toughness, wear resistance, and swelling resistance. It has demonstrated performance advantages in the fields of submarine cables, solar energy, medical treatment, and 3D printing. . In the industry, cyclododecanone oxime is often used as an acidic catalyst to produce laurolactam through extraction and rearrangement reaction. There a...

AI Technical Summary

Problems solved by technology

[0005] The preparation of laurolactam by cyclododecanone oxime through the extraction and rearrangement process is a strong exothermic reaction. If the heat transfer is not timely or the temperature control is unstable during the reaction process, a large number of side reactions will be caused, and the reactants will be seriously carbonized, which will affect the product. quality

At the same time, there is a tailing phenomenon in this reaction, that is, the reaction rate is fast in the early stage of the reaction, and the heat release power is large; the reaction rate is slow in the later stage, and the heat release is small, and a certain aging time is required to achieve the required yield.

If there is too much heat transfer in the later stage of the reaction, the conversion rate of the reactant will be reduced

At the same time, the viscosity of the reaction material is sensitive to temperature. If the temperature is too low, the viscosity of the material will increase sharply, which is not conducive to the mixing and reaction of liquid and liquid.

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