Prep. of epsilon-hexanolactam

A technology of caprolactam and cyclohexanone oxime, applied in the field of ε-caprolactam preparation, can solve the problem of high equipment cost

Inactive Publication Date: 2007-12-12
SUMITOMO CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method also requires specific equipment, such as vacuum pumps and vacuum crystallizers, which still makes the equipment cost high

Method used

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  • Prep. of epsilon-hexanolactam
  • Prep. of epsilon-hexanolactam

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach

[0042] Referring to Fig. 1, an embodiment of the method of the present invention, a method for continuously producing ε-caprolactam, is described below. In Fig. 1, reference numeral 1, 3 and 7 all represent crystallization vessel, 2, 4 and 8 represent solid-liquid separation device, 5 represent the device of washing crystallization, 6 represent dissolution vessel, 9 represent cooling device, 10-16 Represents a pipeline.

[0043] The molten crude ε-caprolactam prepared in dissolution vessel 6 enters crystallization vessel 1 via line 10 . At the same time, the solvent cooled in the cooling device 9 enters the crystallization vessel 1 through the line 11 . In the preparation of the molten crude ε-caprolactam in the dissolution vessel 6, solvents including aliphatic hydrocarbons may be used. At this time, the obtained ε-caprolactam contains a small amount of cyclohexanone oxime compared to the case where no aliphatic hydrocarbon-containing solvent is used in the dissolution vess...

Embodiment 1

[0069] The process for the continuous production of ε-caprolactam is carried out as follows. Flow rates of liquids are expressed in parts by weight per unit of time (unless otherwise stated).

[0070] A gas-phase Beckmann rearrangement reaction of cyclohexanone oxime (hereinafter referred to as "OXM") was carried out at 380°C in the presence of methanol using a fluidized bed reactor packed with a high-silica zeolite catalyst to obtain crude ε-caprolactam-containing reaction mixture.

[0071] The reaction mixture was distilled to remove methanol, low-boiling impurities and high-boiling impurities to obtain crude ε-caprolactam with a purity of 99.131% containing 13 ppm OXM, 398 ppm MTHI and 430 ppm OHP.

[0072] The crude ε-caprolactam (200 parts by weight; 75 ℃) and the mixed solvent (400 parts by weight; 5 ℃) of cyclohexane and n-heptane (weight ratio 1:3) obtained above and melted in advance were continuously poured into the The jacket keeps the crystallization vessel at 5...

Embodiment 2

[0081] A liquid mixture of OXM, methanol and water (weight ratio 1:1.8:0.052) was injected into a fluidized bed reactor packed with high silica zeolite catalyst through an evaporator, and the reaction temperature was 380 °C and the residence time was 8 The Beckmann rearrangement reaction of OXM was carried out under the conditions of seconds to obtain a reaction mixture containing crude ε-caprolactam.

[0082]The reaction mixture was distilled to remove methanol, low-boiling impurities, and high-boiling impurities to obtain crude ε-caprolactam with a purity of 99.08% containing 188 ppm OXM, 469 pm MTHI and 205 ppm OHP.

[0083] A mixture of the resulting crude ε-caprolactam (55 g) and n-heptane (82.5 g) was prepared and maintained at 70°C. Separately, n-heptane (41.25 g) was cooled with ice. The mixture of crude ε-caprolactam and n-heptane was continuously poured (over 10 minutes) into a flask filled with other n-heptane (41.25 g) together with cooled n-heptane at a temperatu...

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Abstract

A high purity epsi-caprolactam is prepared by pouring a molten crude epsi-caprolactam and a solvent comprising an aliphatic hydrocarbon and having a lower temperature than that of the crude epsi-caprolactam, into a vessel and mixing them to obtain a first slurry containing a crystallized epsi-caprolactam. The slurry is then subjected to a solid-liquid separation to obtain epsi-caprolactam and a first liquid phase. This process can effectively remove impurities from a crude epsi-caprolactam, which is obtained by for example, subjecting cyclohexanone oxime to the Beckmann rearrangement.

Description

technical field [0001] The present invention relates to a preparation method of ε-caprolactam, in particular to a method for crystallizing ε-caprolactam from impurity-containing crude ε-caprolactam to prepare high-purity ε-caprolactam. Background technique [0002] ε-caprolactam is an important compound that can be used as an intermediate for the preparation of amides such as nylon-6, and many methods for preparing ε-caprolactam are known. For example, ε-caprolactam can be prepared by Beckmann rearrangement of cyclohexanone oxime in the presence of an acidic medium such as oleum. Disadvantages with this method include the production of large amounts of ammonium sulfate. [0003] The above process can be improved by using a solid catalyst for gas-phase Beckmann rearrangement. Solid catalysts used in gas-phase Beckmann rearrangement include boric acid catalysts, silica-alumina catalysts, solid phosphoric acid catalysts, composite metal oxide catalysts, and zeolite catalysts....

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D223/10C07D201/18C07B61/00C07D201/16
CPCC07D201/16
Inventor 津泰基海田博之深尾正美
Owner SUMITOMO CHEM CO LTD
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