Preparation method of caprolactam
A technology of caprolactam and crude caprolactam, which is applied in the field of caprolactam preparation, can solve the problems of poor economical production of caprolactam, low yield and quality of caprolactam, and achieve the effects of less types and contents, high selectivity and improved stability
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[0035] The first aspect of the present invention provides a kind of preparation method of caprolactam, this method comprises the following steps:
[0036] (1) Under the condition of cyclohexanone oxime gas-phase Beckmann rearrangement reaction, in the presence of ethanol, the cyclohexanone oxime is contacted with the catalyst to react;
[0037] (2) separating the reaction product obtained in step (1) to obtain an ethanol solution of crude caprolactam, and then separating the ethanol solution of crude caprolactam to obtain ethanol and crude caprolactam;
[0038] (3) removing impurities with a lower boiling point than caprolactam in the crude caprolactam to obtain light-removed products;
[0039] (4) mixing the light-removing product with a crystallization solvent for crystallization, and solid-liquid separation to obtain crystalline crystals;
[0040] (5) subjecting the crystalline crystals to a hydrogenation reaction;
[0041]The crystallization solvent contains 0.1-2% by we...
specific Embodiment approach
[0054] The present invention has a wide selection range for the content of silicon and oxygen in the molecular sieve. In a specific embodiment, based on the total amount of molecular sieve, in the molecular sieve, the content of silicon, oxygen and metal The sum of the contents of the elements is 100%.
[0055] According to a preferred embodiment of the present invention, based on the total amount of molecular sieves, the content of the metal elements in the molecular sieves is 6-90 μg / g, preferably 30-80 μg / g. Specifically, for example, 30 μg / g, 35 μg / g, 40 μg / g, 45 μg / g, 50 μg / g, 55 μg / g, 60 μg / g, 70 μg / g, 75 μg / g, 80 μg / g, and among these values Any value in the range formed by any two of . In this preferred embodiment, the catalytic performance of the catalyst is better, which is more conducive to improving the conversion rate of cyclohexanone oxime and the selectivity of caprolactam. In the present invention, if the content of the metal element is too much, it is possib...
Embodiment approach
[0057] According to a preferred embodiment of the present invention, the metal element is selected from Al, Ga, Ge, Ce, Ag, Co, Ni, Cu, Zn, Mn, Pd, Pt, Cr, Fe, Au, Ru, Rh, Pt , Rh, Ti, Zr, V, Mo and W elements at least one.
[0058] Still further preferably, the metal element has an ion valence state of +3 valence and / or an ion valence state of +4 valence. The inventors of the present invention found in the course of research that the use of metal elements with +3 valence and / or +4 valence is more conducive to metal elements entering the molecular sieve framework, and more conducive to charge balance.
[0059] According to the present invention, the metal element is further preferably at least one of Fe, Al, Ga, Ge, Cr, Ti, Zr and Ce elements. In this preferred embodiment, it is more beneficial to improve the performance of the catalyst, thereby improving the conversion rate of cyclohexanone oxime and the selectivity of caprolactam.
[0060] According to the present inventio...
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Abstract
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