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Catalyst for preparing caprolactam from cyclohexanone-oxime by liquid-phase Beckmann rearrangement

A technology of Beckmann rearrangement and cyclohexanone oxime, which is applied in the field of caprolactam preparation, can solve the problems of complex preparation process and difficult recovery, and achieve the effect of low reaction temperature and convenient operation

Active Publication Date: 2012-09-12
HEBEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] Aiming at the shortcomings of the liquid catalyst in the existing liquid-phase Beckmann rearrangement of cyclohexanone oxime to prepare caprolactam and the problems of complex preparation process and difficult recovery of the solid catalyst, the present invention provides a liquid-phase Beckmann rearrangement of cyclohexanone oxime Catalyst for preparing caprolactam and its preparation method can significantly simplify the catalyst preparation process, the catalyst is easy to recycle, and the process conditions are simple

Method used

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  • Catalyst for preparing caprolactam from cyclohexanone-oxime by liquid-phase Beckmann rearrangement
  • Catalyst for preparing caprolactam from cyclohexanone-oxime by liquid-phase Beckmann rearrangement
  • Catalyst for preparing caprolactam from cyclohexanone-oxime by liquid-phase Beckmann rearrangement

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Mesoporous molecular sieve HMS supported phosphotungstic heteropolyacid HPW (HPW / HMS) catalyst was prepared by equal volume impregnation method: Weigh 0.2 g phosphotungstic heteropolyacid (H 3 PW 12 o 40 ·xH 2 O) Dissolve in 10 ml deionized water to obtain a clear solution. Take 2.0 g of HMS and place it in the above clear solution, and let it stand at room temperature for 24 h. The white solid powder was obtained by rotary evaporation at 60°C, and calcined at 180°C for 9 h to obtain HPW / HMS with a loading of HPW of 10 wt.%.

[0031] in the attached figure 1 Among them, HPW has two obvious characteristic diffraction peaks at 2θ=10.3° and 25.4°, indicating that the HPW used in the experiment has a Keggin structure, and the diffraction intensity of these two characteristic peaks is very strong, and the peak shape is sharper, indicating that the HPW has a Keggin structure. The degree of crystallinity is very high, and the crystal form is relatively perfect.

[0032] ...

Embodiment 2~5

[0036] The preparation of the HPW / HMS with a load of 20wt.%, 30wt.%, 40wt.% and 50wt.% is the same as in Example 1, except that phosphotungstic heteropolyacid (H 3 PW 12 o 40 ·xH 2 O) have masses of 0.4 g, 0.6 g, 0.8 g and 1.0 g, respectively.

[0037] in the attached image 3 Among them, when the loading of HPW is 40wt.%, the characteristic diffraction peaks of HPW appear in many places such as 2θ=10° and 25°, and the peak shape of these characteristic diffraction peaks is sharp and the peak intensity is strong. XRD technology The existence of HPW crystals was detected by means, indicating that when the loading of HPW increased to 40wt.%, aggregation began to occur on the surface of HMS to form HPW crystals.

[0038] The activity test operation steps and reaction conditions of the catalyst are the same as in Example 1. The experimental results are shown in Table 1.

[0039] Table 1 Effect of HPW loading on Beckmann rearrangement of cyclohexanone oxime

[0040] ...

Embodiment 6～7

[0042] The preparation steps and reaction conditions of the catalyst in Example 2 are the same, except that the calcination temperatures of the supported catalyst HPW / HMS are 240° C. and 300° C. respectively. The experimental results are shown in Table 2.

[0043]

[0044] Table 2 Effect of calcination temperature of HPW / HMS on the Beckmann rearrangement reaction of cyclohexanone oxime

[0045] Example Calcination temperature (°C) Yield of caprolactam (%) Selectivity of caprolactam (%) 2 180 44.2 82.3 6 240 55.2 84.1 7 300 55.5 78.0

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Abstract

The invention relates to a catalyst for preparing caprolactam from cyclohexanone-oxime by liquid-phase Beckmann rearrangement, which is a supported solid acid catalyst using heteropoly acid as an active component and mesoporous molecular sieve (HMS) as a support, wherein the support capacity of the heteropoly acid is 10-70 wt%. The heteropoly acid is heteropolyphosphatotungstate (HPW). Compared with the existing catalyst, the invention has the following advantages: (1) the catalyst adopts heterogeneous catalysis, and can be recycled in a vacuum filtration mode; (2) the heteropoly acid is used as the catalyst, and thus, the invention is environment-friendly, can not generate low-value byproduct ammonium sulfate, and does not corrode the equipment; (3) the reaction is carried out under ordinary pressure, the reaction temperature is not high, the requirements for reaction equipment are not high, and the operation is convenient; and (4) the yield and selectivity of caprolactam are high, respectively reaching 82.5% and 87.1%.

Description

technical field [0001] The invention relates to the preparation of caprolactam, in particular to a catalyst for preparing caprolactam by liquid-phase Beckmann rearrangement of cyclohexanone oxime. Background technique [0002] ε-caprolactam is an important organic chemical raw material, its appearance is white crystal or crystalline powder, and it is easily soluble in water, ethanol, ether, chloroform and benzene. Caprolactam is mainly used to produce polyamide-6 fiber and polyamide-6 engineering plastics. In addition, caprolactam can also be used to produce antiplatelet drug 6-aminocaproic acid, resin and film. [0003] The Beckmann rearrangement reaction equation of cyclohexanone oxime is as follows: [0004] [0005] The Beckmann rearrangement of cyclohexanone oxime is an acid-catalyzed reaction. The current industrial production of caprolactam uses oleum or concentrated sulfuric acid as a catalyst. First, cyclohexanone oxime is converted into caprolactam sulfate, and...

Claims

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Application Information

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IPC IPC(8): B01J29/03C07D223/10C07D201/04
CPCY02P20/52Y02P20/584
Inventor 程庆彦刘玉扑周杰赵新强王延吉
Owner HEBEI UNIV OF TECH
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