The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 30, 2024
Filed:
Mar. 25, 2021
Zhejiang Hengyi Petrochemical Research Institute Co., Ltd., Hangzhou, CN;
Shibiao Cheng, Zhejiang, CN;
Songlin Wang, Zhejiang, CN;
Xi Li, Zhejiang, CN;
Han Wang, Zhejiang, CN;
Fei Shen, Zhejiang, CN;
Xinping Zhang, Zhejiang, CN;
Zhaobin Jiang, Zhejiang, CN;
Zhimin Hu, Zhejiang, CN;
ZHEJIANG HENGYI PETROCHEMICAL RESEARCH INSTITUTE CO., LTD., Hangzhou, CN;
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.