Refining process and refining system of caprolactam
US11459302B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 2021 |
| Grant date | Oct 4, 2022 |
| Priority date | — |
| Expiry date | Jun 4, 2041 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D201/16
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.