Sulfuric Acid → 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-5-chlorobenzotriazole-N-oxide

Participants

Reaction Conditions

Reaction Steps

2-nitro-4-chloro-2'-hydroxy-3'-t-butyl-5'-methylazobenzene 23.2 g was added to a mixture of n-butanol 60 g, water 10.6 g and 97% sodium hydroxide 6.9 g, and the resultant mixture was stirred while raising temperature to 65° C. Thereafter, the mixture was cooled to 50° C., and 9-fluorenone 1.5 g was added to the mixture. The reaction mixture was then heated to 90° C. in one hour, and the mixture was stirred at 90°~96° C. for five hours to effect reaction, thus almost all of the azobenzene having disappeared to finish the reaction of Process (b). Thereafter, water 50 ml was added to the reaction mixture, and the mixture was neutralized to pH 8~9 with 62% sulfuric acid 10 g. The neutralized liquor was cooled to 20° C. to precipitate a crystal. The crystal thus precipitated was separated by filtration, thus producing the wet product 22.9 g of 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-5-chlorobenzotriazole-N-oxide (dry product: 20.6 g, yield: 93.0%, melting point: 160°~163° C.).

Provenance & Evidence