Fluorescent compounds for use in industrial water systems
US6358746B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 1999 |
| Grant date | Mar 19, 2002 |
| Priority date | — |
| Expiry date | Nov 8, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/13
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Fluorescent compounds of the formula: wherein R1 and R2 are either both SO3M, or one of R1 and R2 is SO3M and the other is COOM, where M is selected from the group consisting of H, Na, K, Rb, Cs, Li or ammonium, are described and claimed. These inert flurorescent compounds have been found to be resistant to oxidizing biocides. One process for making these compounds is described and claimed as the condensation between a 1,8-naphthalic anhydride possessing the desired functionalities and the appropriately substituted o-phenylene diamine. Alternatively, o-amino-nitro-aromatics may be condensed with the various 1,8-naphthalic anhydrides when the in situ reduction of the nitro group is accomplished with a suitable reducing agent such as iron powder. The resulting fluorescent compounds can be used as inert fluorescent tracers in industrial water systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.