Abstract: The present disclosure discloses a method for preparing caprolactam including: (1) contacting cyclohexanone oxime with a catalyst to carry out reaction in the presence of ethanol and under the condition of gas phase Beckmann rearrangement reaction of cyclohexanone oxime; (2) separating the reaction product obtained in step (1) to produce an ethanol solution of crude caprolactam, and then separating the ethanol solution of crude caprolactam to obtain ethanol and crude caprolactam; (3) removing impurities with boiling points lower than that of caprolactam in the crude caprolactam to obtain a light component removal product; (4) mixing the light component removal product with a crystallization solvent to carry out crystallization and solid-liquid separation to obtain a crystalline crystal; (5) subjecting the crystalline crystal to a hydrogenation reaction; wherein the crystallization solvent contains 0.1-2 wt % of ethanol.

Abstract: A refining process includes steps of subjecting crude caprolactam to a first evaporative crystallization and a first solid-liquid separation to obtain a first caprolactam crystal and a first crystallization mother liquor; washing the first caprolactam crystal to obtain a second caprolactam crystal; optionally concentrating the first crystallization mother liquor to perform a second evaporative crystallization and a second solid-liquid separation to obtain a third caprolactam crystal and a second crystallization mother liquor; subjecting the third caprolactam crystal to a second washing to obtain a fourth caprolactam; optionally concentrating the second crystallization mother liquor to perform thermostatic crystallization, performing separation to obtain a fifth caprolactam crystal and a third crystallization mother liquor; washing the fifth caprolactam crystal to obtain a sixth caprolactam crystal; and subjecting the second caprolactam crystal to a hydrogenation reaction.

Abstract: A refining process includes steps of subjecting crude caprolactam to a first evaporative crystallization and a first solid-liquid separation to obtain a first caprolactam crystal and a first crystallization mother liquor; washing the first caprolactam crystal to obtain a second caprolactam crystal; optionally concentrating the first crystallization mother liquor to perform a second evaporative crystallization and a second solid-liquid separation to obtain a third caprolactam crystal and a second crystallization mother liquor; subjecting the third caprolactam crystal to a second washing to obtain a fourth caprolactam; optionally concentrating the second crystallization mother liquor to perform thermostatic crystallization, performing separation to obtain a fifth caprolactam crystal and a third crystallization mother liquor; washing the fifth caprolactam crystal to obtain a sixth caprolactam crystal; and subjecting the second caprolactam crystal to a hydrogenation reaction.

Abstract: The present disclosure discloses a method for preparing caprolactam including: (1) contacting cyclohexanone oxime with a catalyst to carry out reaction in the presence of ethanol and under the condition of gas phase Beckmann rearrangement reaction of cyclohexanone oxime; (2) separating the reaction product obtained in step (1) to produce an ethanol solution of crude caprolactam, and then separating the ethanol solution of crude caprolactam to obtain ethanol and crude caprolactam; (3) removing impurities with boiling points lower than that of caprolactam in the crude caprolactam to obtain a light component removal product; (4) mixing the light component removal product with a crystallization solvent to carry out crystallization and solid-liquid separation to obtain a crystalline crystal; (5) subjecting the crystalline crystal to a hydrogenation reaction; wherein the crystallization solvent contains 0.1-2 wt % of ethanol.

Abstract: The present disclosure discloses a MFI topological structure silicon molecular sieve, a preparation method thereof and a catalyst containing the MFI topological structure silicon molecular sieve, wherein the molecular sieve containing a silicon element, an oxygen element and a metallic element, the ions of said metallic element have a Lewis acid characteristic; the content of the metallic element in the molecular sieve is within a range of 5-100 ?g/g based on the total amount of the molecular sieve; the BET specific surface area of the molecular sieve is within a range of 400-500 m2/g.

Abstract: The present invention discloses a process for the ammoximation of carbonyl compounds, wherein a reaction in a liquid reaction system comprising a carbonyl compound, ammonia and hydrogen peroxide is carried out in the presence of a sillicon-containing catalyst, characterized in that a liquid silicon-containing assistant is added to the reaction system so that the silicon concentration in the system reaches a range of between 0.1 and 10000 ppm. In the process according to the present invention, the deactivation of catalyst due to dissolution of silicon in the catalyst can be reduced, thus lifetime of the catalyst extended and the stable operation time elongated.

Abstract: The present invention discloses a process for the ammoximation of carbonyl compounds, wherein a reaction in a liquid reaction system comprising a carbonyl compound, ammonia and hydrogen peroxide is carried out in the presence of a sillicon-containing catalyst, characterized in that a liquid silicon-containing assistant is added to the reaction system so that the silicon concentration in the system reaches a range of between 0.1 and 10000 ppm. In the process according to the present invention, the deactivation of catalyst due to dissolution of silicon in the catalyst can be reduced, thus lifetime of the catalyst extended and the stable operation time elongated.