Catalyst for preparing caprolactam from cyclohexanone-oxime by liquid-phase Beckmann rearrangement
A technology of Beckmann rearrangement and cyclohexanone oxime, which is applied in molecular sieve catalysts, physical/chemical process catalysts, chemical recovery, etc., can solve the problems of difficult recovery and complicated preparation process, and achieve low reaction temperature and convenient operation Effect
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Embodiment 1
[0029] 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.%.
[0030] 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 The degree of crystallinity is very high, and the crystal form is relatively perfect.
[0031] in the attached figure...
Embodiment 2~5
[0035] 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.
[0036] 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.
[0037] 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.
[0038] Table 1 Effect of HPW loading on Beckmann rearrangement of cyclohexanone oxime
[0039] ...
Embodiment 6～7
[0041] 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.
[0042] Table 2 Effect of calcination temperature of HPW / HMS on the Beckmann rearrangement reaction of cyclohexanone oxime
[0043] 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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