Caprolactam preparation method

The technology of caprolactam and inner sleeve is applied in the field of preparation of caprolactam, which can solve the problems of long process, limit the expansion of the production capacity of the device or the construction of a new device, etc., and achieve the effect of uniform material concentration and temperature

CN105085354AActive Publication Date: 2015-11-25CHINA PETROLEUM & CHEM CORP +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2015-11-25

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Abstract

The invention provides a caprolactam preparation method by which an amidation liquid from a caprolactam preparation process through a toluene method is in contact with cyclohexanone-oxime to carry out Beckmann rearrangement reaction. The caprolactam preparation method is characterized in that the Beckmann rearrangement reaction is carried out in a jet-loop reactor; reaction heat is evaporated and removed through an organic solvent in cyclohexanone-oxime; the jet-loop reactor is provided with a mixed spray nozzle, an inner sleeve and an outer sleeve; inner sleeve space and an annular space between the inner sleeve and the outer sleeve are communicated up and down; in the mixed spray nozzle, the amidation liquid is firstly pre-mixed with a cyclohexanone-oxime organic solution from an inner tube of the mixed spray nozzle through the annular space between the inner tube and the outer tube of the mixed spray nozzle; after being pre-mixed, materials form a jet material flow which enters into the inner sleeve; density difference exists between the jet material flow in the inner sleeve and the material flow in the annular space between the inner sleeve and the outer sleeve, so that the jet flow in the inner sleeve is upward, and the material flow in the annular space between the inner and the outer sleeves is downward, thereby forming a circular flow of the material flow. The method can be used for realizing reduction of production of a byproduct ammonium sulfate and lowering the production cost.
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Description

technical field

[0001] The invention relates to a preparation method of caprolactam, in particular to a method for preparing caprolactam through Beckmann rearrangement reaction by contacting an amidation solution of a toluene method for producing caprolactam with cyclohexanone oxime. Background technique

[0002] Caprolactam is an important organic chemical raw material, mainly used in the production of nylon 6 fiber and nylon 6 engineering plastics. The caprolactam preparation methods currently used in industrial production mainly include: cyclohexanone-hydroxylamine production process or ammoximation process (referred to as "benzene process"), cyclohexane photonitrosation process and SNIA toluene process. Among them, the production process of cyclohexanone-hydroxylamine uses benzene as raw material, cyclohexane is hydrogenated to cyclohexane, cyclohexanone is oxidized to cyclohexanone, cyclohexanone is oximated or ammoximated to produce cyclohexanone oxime, cyclohexanone ...

Examples

Embodiment 1

[0039] This example illustrates the method of the invention.

[0040] The diameter ratio of the inner sleeve to the outer sleeve of the reactor is 0.67, and the height of the inner sleeve is 3 times the diameter of the outer sleeve. The inner tube diameter of the mixing nozzle is 10mm, and the ratio of the inner tube diameter to the outer tube diameter is 0.75, and the linear velocity of the cyclohexanone oxime organic solution from the inner tube of the mixing nozzle is 40.5m / s, and the amidation liquid is in the inner tube of the mixing nozzle and The linear velocity of the annulus between the outer tubes is 24.9m / s. The upper part of the reactor is provided with an enlarged head section for the separation of gas-liquid two phases, and the ratio of the diameter of the enlarged head section to the diameter of the outer sleeve is 2:1.

[0041] Cyclohexanone oxime was fed as a hexane solution of cyclohexanone oxime at a concentration of 15 wt%. The feed rate of cyclohexanone ...

Embodiment 2

[0051] This example illustrates the method provided by the invention.

[0052] The reaction conditions are the same as in Example 1, except that the ratio of the diameter of the reactor inner sleeve to the outer sleeve is 0.67, and the height of the inner sleeve is 3 times the diameter of the outer sleeve. The inner tube diameter of the mixing nozzle is 15mm, and the ratio of the inner tube diameter to the outer tube diameter is 0.65, and the linear velocity of the cyclohexanone oxime organic solution from the inner tube of the mixing nozzle is 18.0m / s, and the amidation solution passes through the inner tube of the mixing nozzle and The linear velocity of the annulus between the outer tubes is 6.3m / s. The upper part of the reactor is equipped with an enlarged head section for the separation of gas-liquid two-phase, the ratio of the diameter of the enlarged head section to the diameter of the outer sleeve is 4:1

[0053] The reaction results are as follows: the conversion rat...

Embodiment 3

[0055] This example illustrates the method provided by the invention.

[0056] The reaction conditions are the same as in Example 1, except that the ratio of the diameter of the reactor inner sleeve to the outer sleeve is 0.62, and the height of the inner sleeve is 5 times the diameter of the outer sleeve. The inner pipe diameter of the mixing nozzle is 15mm, and the ratio of the inner pipe diameter to the outer pipe diameter is 0.5, and the linear velocity of the cyclohexanone oxime organic solution from the inner pipe of the mixing nozzle is 18.0m / s, and the amidation liquid passes through the inner pipe of the mixing nozzle and The linear velocity of the annulus between the outer tubes is 2.9 m / s. The upper part of the reactor is equipped with an enlarged head section for the separation of gas-liquid two-phase, the ratio of the diameter of the enlarged head section to the diameter of the outer sleeve is 3:1

[0057] The reaction results are as follows: the conversion rate ...