A kind of method for preparing laurolactam by extraction rearrangement reaction of cyclododecanone oxime

Abstract

The invention discloses a method for preparing laurolactam by extraction and rearrangement reaction of cyclododecanone oxime. The cyclododecanone oxime is extracted from the solvent phase to the catalyst phase by stirring and mixing, and the reaction kettle is liquid-liquid two-phase, and the reaction is carried out in the catalyst phase; (2) the materials in the extraction kettle are subjected to the extraction reaction through the external circulation pump and the external circulation cooler. Heat and part of the rearrangement reaction heat are removed; a material is drawn from the outlet of the external circulation pump as the feed of the rearrangement kettle, and another material is drawn from the outlet of the external circulation cooler as the inlet medium of the inner coil for heat removal of the rearrangement kettle; (3) The material at the outlet of the coil in the rearrangement kettle is mixed with the material at the outlet of the outer circulating cooler of the extraction kettle and then enters the extraction kettle, and the material in the rearrangement kettle enters the downstream neutralization process. The heat transfer method of the invention has a small temperature difference in the rearrangement kettle, can effectively prevent the material from being overcooled, and ensure the conversion rate of the reaction material.

Description

Technical field: [0001] The invention relates to a method for preparing laurolactam by extraction and rearrangement reaction of cyclododecanone oxime, which is especially suitable for extraction and rearrangement reaction of cyclododecanone oxime solution with a solvent in liquid-liquid two-phase under acidic catalyst conditions Continuous process for the preparation of laurolactam. Background technique [0002] Laurolactam is an important organic chemical raw material, which is polymerized to obtain nylon 12. Compared with general nylon (such as nylon 6), nylon 12 has the advantages of low water absorption, high toughness, wear resistance and swelling resistance as a special nylon product. It has shown performance advantages in submarine cables, solar energy, medical treatment, 3D printing and other fields. . In industry, laurolactam is often prepared by extraction and rearrangement reaction of cyclododecanone oxime under the use of an acidic catalyst, and there are many ...

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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