反应详情

12 g of 5-(3,5-bis-(methoxycarbonyl)-phenylazo)-2-hydroxyphenylacetic acid, 350 ml of water and 7 g of sodium hydroxide were boiled for 1 hour. 50 ml of ethanol was added, and the solution was diluted with water to 500 ml. The hot solution was acidified with hydrochloric acid to pH 2 and cooled. The crystals were filtered off, washed with water and dried.

1. temperaturecooled
2. filtrationThe crystals were filtered off
3. washwashed with water
4. customdried