Purification of cyanuric acid
US4963674A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1989 |
| Grant date | Oct 16, 1990 |
| Priority date | — |
| Expiry date | Dec 21, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D251/32
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for the purification of crude cyanuric acid containing aminotriazine compounds as impurities which comprises digesting the crude cyanuric acid in an aqueous solution containing low concentrations of a mineral acid. The mineral acid is, for example sulfuric acid, nitric acid, hydrochloric acid, or phosphoric acid. The digestion is operated at a temperature in the range of from about 120.degree. C. and about 220.degree. C. and autogenous pressure using a stoichiometric ratio of sulfuric acid to aminotriazine compounds of less than 1, to produce a slurry of purified cyanuric acid in an acid depleted ammonium sulfate solution. Purification of cyanuric acid by the process of the present invention permits a substantial reduction in the amounts of acid used in the digestion and the base required for ammonia stripping and neutralization of the spent acid from the digestion. This provides significant cost savings in the digestion and waste treatment methods.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.