Method for recovering and producing C4-C6 dicarboxylate from alkaline waste solution generated in caprolactam preparation process
US6825379B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 2002 |
| Grant date | Nov 30, 2004 |
| Priority date | — |
| Expiry date | Feb 24, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C67/58
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention relates to a method for recovering and producing C4-C6 dicarboxylates from an alkaline waste solution generated in a caprolactam preparation process, in which the alkaline waste solution is treated with sulfuric acid to separate into an aqueous phase and an organic phase, allowing valuable substances contained in the organic phase to be firstly oxidized and converted into dicarboxylic acids. The dicarboxylic acids then undergo concentration, esterification and distillation processes, so as to obtain desirable C4-C6 dicarboxylates with high purity. This therefore provides an efficient and improved method for effectively recovering most valuable substances from the alkaline waste solution, so that economic benefits in recovery are greatly raised.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.