反应详情

An aqueous Raney nickel paste (containing 0.5 g of metallic nickel) and 5.0 g of a 80% aqueous hydrazine hydrate solution were added dropwise to 200 g of an aqueous solution containing 16.2 g of 2-quinoxalinol-4-oxide and 8 g of sodium hydroxide at a temperature of 40° to 50° C., and the resulting mixture was stirred at 40° to 70° C. for 5 hr, whereby the reducing reaction was terminated. The catalyst was then recovered by filtration, and 35% hydrochloric acid was added dropwise to the filtrate at 50° to 60° C. to adjust the pH to 4. The precipitated crystal was collected by filtration, washed with water and dried to give 13.4 g (yield 92%) of 2-quinoxalinol with melting point of 268° C.

1. customwhereby the reducing reaction
2. customwas terminated
3. filtrationThe catalyst was then recovered by filtration, and 35% hydrochloric acid
4. additionwas added dropwise to the filtrate at 50° to 60° C.
5. filtrationThe precipitated crystal was collected by filtration
6. washwashed with water
7. customdried