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Process for producing epsilon-caprolactam

A technology of caprolactam and cyclohexanone oxime, which is applied in the field of manufacturing ε-caprolactam with low free alkalinity, can solve the problems such as the negative impact of polymerization into nylon reaction

Inactive Publication Date: 2001-06-06
SUMITOMO CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is known that high free alkalinity in the product ε-caprolactam negatively affects the polymerization to nylon

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0039] The present invention is illustrated in detail by the following examples, which are embodiments of the invention and should not be construed as limiting the scope of the invention.

[0040] In the present invention, the conversion rate of cyclohexanone oxime, the selectivity of ε-caprolactam and the selectivity of AAH are calculated respectively by using the following formula.

[0041] Cyclohexanone oxime conversion rate (%)=[(X-Y) / X]×100

[0042] ε-caprolactam selectivity (%)=[Z / (X-Y)]×100

[0043] AAH selectivity (%)=[W / (X-Y)]×100 where X, Y and Z are expressed as follows:

[0044] X: The molar amount of cyclohexanone oxime added

[0045] Y: molar amount of unreacted cyclohexanone oxime

[0046] Z: molar amount of ε-caprolactam in the product

[0047] W: molar amount of AAH in the product Reference Example 1

[0048] 0.375g of catalyst containing crystalline zeolite was installed in a quartz reaction tube with an inner diameter of φ6mm and a length of about 60cm,...

reference example 2～4

[0049] 0.375 g of a catalyst containing crystalline zeolite was packed in a quartz reaction tube with an inner diameter of φ10 mm and a length of about 60 cm, and heated to 325° C. (the height of the catalyst layer was about 23 mm). The raw material with cyclohexanone oxime / alcohol / water weight ratio of 1 / 1.89 / 0.052 was introduced at a speed of 8.54g / h under a nitrogen flow of 70cc / min, and the reaction gas was collected from the outlet of the reaction tube in a dry ice / methanol bath. The temperature of the catalyst layer is 360°C to 370°C. The reaction liquid was analyzed by gas chromatography. The results are shown in Table 1. Reference example 5

[0050] Reference example

2

3

4

5

alcohol name

A (molar ratio)

B(%)

C(%)

D(%)

Methanol

6.4

99.73

95.37

0.79

ethanol

4.4

99.23

95.78

0.32

n-propanol

3.4

97.69

94.92

0.04

n-propan...

example 1

[0055] 8.50 g of AMH and 6.77 g of water were added to 319 g of the reaction liquid obtained by the gas-phase Beckmann rearrangement reaction (which contained 15.8 wt % lactam and 0.19 wt % AMH through gas chromatography analysis). The reaction liquid was refluxed in the rectification tower, the tower was equipped with about 5 trays of glass Helipack packing, the reflux ratio was 1, the bath temperature was raised from 80°C to 130°C over 3 hours, and methanol was distilled off. The bath was controlled at atmospheric pressure and heated at 140° C. for 3 hrs, then cooled to give 88.9 g of remaining liquid. Gas chromatographic analysis gave a lactam content of 63.6%, and no AMH was detected. The lactam yield was 74.2% based on AMH.

[0056] The following formulas were used to calculate the lactam yield and the residual ratio of AMH based on AMH respectively.

[0057] Lactam yield, based on AMH (%)

[0058] =[(B-A) / C]×100

[0059] Residue ratio of AMH (%)=(D / C)×100 ...

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PUM

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Abstract

A process for producing epsilon -caprolactam, characterized by subjecting cyclohexanone oxime to the vapor-phase Beckmann rearrangement reaction in the presence of an alcohol using a solid catalyst and treating the resultant reaction product containing a 1-aza-2-alkoxy-1-cycloheptene with water to remove the 1-aza-2-alkoxy-1-cycloheptene from the reaction product. The thus-obtained epsilon -caprolactam has a 1-aza-2-alkoxy-1-cycloheptene content of generally 100 ppm or lower, desirably 25 ppm or lower, preferably 10 ppm or lower. It hence has a low basicity with respect to free bases and is of desirable quality.

Description

field of invention [0001] The present invention relates to a process for the manufacture of ε-caprolactam having a low free alkalinity. Specifically, the method for producing ε-caprolactam with low free alkalinity in the present invention comprises: in the presence of alcohol, using a solid catalyst, making cyclohexanone oxime undergo a gas-phase Beckmann rearrangement reaction to produce ε-caprolactam. Background of the invention [0002] ε-caprolactam is an important compound as an intermediate for the manufacture of nylon-6. The production of ε-caprolactam from cyclohexanone oxime by gas-phase Beckmann rearrangement using solid catalysts is known; Aluminum catalysts, solid phosphoric acid catalysts, composite metal oxide catalysts and zeolite-based catalysts, etc. In addition, Japanese Patent Application Publication Nos. (JP-A) Nos. 62-123167 and 63-54358 have proposed examples of using high-silica-type metallosilicate catalysts. The selectivity of gas phase Beckmann r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D201/04
CPCC07D201/04C07D201/16
Inventor 深尾正美高峰宽中村智和
Owner SUMITOMO CHEM CO LTD
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