Process for the preparation of benozotriazoles and their polymers, and 2(2-hydroxy-5-isopropenylphenyl)2H-benzotriazole produced thereby
US4812575A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 29, 1983 |
| Grant date | Mar 14, 1989 |
| Priority date | — |
| Expiry date | Sep 29, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F12/32
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The compound 2(2-hydroxy-5-isopropenylphenyl)2H-benzotriazole (2H5P) is produced by azo coupling of o-nitrophenyl diazonium chloride with p-hydroxyacetophenone, subjecting the resulting isolated azo compound to reductive cyclization with zinc in the presence of sodium hydroxide at a temperature of about 50.degree.-70.degree. C., acidifying the resulting mixture so as to produce (2(2-hydroxy-5-acetylphenyl)2H-benzotriazole (2H5A), acetylating the isolated 2(2-hydroxy-5-acetylphenyl)2H-benzotriazole (2H5A), so as to produce 2(2-acetoxy-5-acetylphenyl)2H-benzotriazole (2A5A), methylating the isolated 2(2-acetoxy-5-acetylphenyl(2H-benzotriazole (2A5A) with a methyl Grignard reagent and dehydrating the isolated reaction product with potassium hydrogen sulfate so as to produce 2(2-hydroxy-5-isopropenylphenyl)2H-benzotriazole (2H5P). The compound is used as a polymerizable ultra violet light stabilizer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.