Process for the preparation of 5-perfluoroalkyl substituted benzotriazole UV absorbers
US6353113B1 · kind B1 · utility
1Cited by
1References
28Claims
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Key dates
| Filing date | Aug 3, 2000 |
| Grant date | Mar 5, 2002 |
| Priority date | — |
| Expiry date | Aug 3, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D249/20
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for preparing 2H-benzotriazole UV absorbers containing a perfluoroalkyl moiety at the 5-position of the benzo ring, preferably a trifluoromethyl group, involves diazotizing the perfluoroalkyl substituted o-nitroaniline using concentrated sulfuric acid plus sodium nitrite or preferably nitrosylsulfuric acid to form the corresponding monoazobenzene intermediate via the diazonium salt intermediate which is reduced to the corresponding 5-perfluoroalkyl substituted 2H-benzotriazole UV absorber compound by conventional reduction means.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.