Process for preparing indigo carmine
US10767054B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 2017 |
| Grant date | Sep 8, 2020 |
| Priority date | — |
| Expiry date | Nov 27, 2037 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA23V2002/00
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
Process for preparing disodium 5,5′-indigosulfonate, the feedstock being indigo, this process including the following steps: i) the indigo is subjected to a sulfonation treatment resulting in a mixture that contains 5,5′-indigosulfonic acid, this process including: ii) a reduction treatment is applied to the mixture obtained in step i), and optionally a purification step, so as to obtain a composition including leuco-5,5′-indigosulfonic acid, iii) the leuco-5,5′-indigosulfonic acid is isolated from the composition resulting from step ii), iv) the leuco-5,5′-indigosulfonic acid resulting from step iii) is oxidized to give disodium 5,5′-indigosulfonate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.