反应详情

温度

60 °C

Example 5 of EP 0,257,151 is duplicated. Water (70 ml), 97% sodium hydroxide (5.2 g), 2-nitro-2'-hydroxy-5'-methylazobenzene (12.9 g) and toluene (10 ml) are mixed and heated to 60° C. After stirring, hydroquinone (0.6 g) is added, and glucose (5.0 g) is added to the mixture over one hour at 40° to 45° C. The mixture is further stirred two hours, and the azobenzene disappears. The reaction liquor is neutralized with 62% sulfuric acid (5.8 g), and is cooled to 20° C. to precipitate a crystal. The crystal thus precipitated is separated filtration to obtain a wet product 12 g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole-N-oxide (dry weight 10.8 g, yield: 90.0%, and melting point: 138° to 140° C.).

1. temperatureis cooled to 20° C.
2. customto precipitate a crystal
3. customThe crystal thus precipitated
4. customis separated
5. filtrationfiltration