Reaction detail

Temperature

45 °C

33.6 g (0.13 mol) of 4-methyl-5-nitrosaccharin are dissolved in 1.2 l of water with warming to 45° C. and 5 g of Pd/C (10% on active carbon) are added. Hydrogen gas is then passed in with vigorous stirring (pressureless hydrogenation). 9 l of H2 are absorbed in the course of 4.5 hours. After cooling to 25° C., the catalyst is filtered off, and the filtrate is concentrated to a volume of 200 ml and then acidified to pH 1. The deposited precipitate is filtered off with suction, washed with water and dried under reduced pressure at 50° C. 23.4 g (0.11 mol=85% of theory) of a white solid of m.p.: 272°-273° C. are obtained.

1. custom9 l of H2 are absorbed in the course of 4.5 hours
2. temperatureAfter cooling to 25° C.
3. filtrationthe catalyst is filtered off
4. concentrationthe filtrate is concentrated to a volume of 200 ml
5. filtrationThe deposited precipitate is filtered off with suction
6. washwashed with water
7. customdried under reduced pressure at 50° C
8. custom23.4 g (0.11 mol=85% of theory) of a white solid of m.p.: 272°-273° C. are obtained