反应详情

100 g of 5-cyano-2,4,6-triiodoisophthalic acid is suspended in 400 ml of concentrated sulfuric acid and heated first under agitation for 30 minutes to 60° C., then for 2 hours to 95° C. The thus-produced, clear solution is then poured on 1.2 kg of ice and stirred for one hour in an ice bath. The thus-precipitated crude product is vacuum-filtered, dissolved under heating in 400 ml of ethanol, and the solution is combined with 70 ml of concentrated sodium hydroxide solution. After several hours of agitation in an ice bath, the thus-separated sodium salt is vacuum-filtered, washed with ethanol, and then dissolved in 200 ml of hot water. After treating the solution with active carbon, the filtrate is precipitated into 150 ml of semiconcentrated sulfuric acid. After several hours of stirring in an ice bath, the precipitate is vacuum-filtered, washed with a small amount of ice-cold water, and dried at 50° C., thus obtaining 84 g (=82% of theory) of 5-carbamoyl- 2,4,6-triiodoisophthalic acid, which conforms in its properties with the product of the alkaline saponification.

1. temperatureheated first under agitation for 30 minutes to 60° C.
2. customThe thus-precipitated crude product
3. filtrationis vacuum-filtered
4. dissolutiondissolved
5. temperatureunder heating in 400 ml of ethanol
6. waitAfter several hours of agitation in an ice bath
7. filtrationthe thus-separated sodium salt is vacuum-filtered
8. washwashed with ethanol
9. dissolutiondissolved in 200 ml of hot water
10. additionAfter treating the solution with active carbon
11. customthe filtrate is precipitated into 150 ml of semiconcentrated sulfuric acid
12. stirringAfter several hours of stirring in an ice bath
13. filtrationthe precipitate is vacuum-filtered
14. washwashed with a small amount of ice-cold water
15. customdried at 50° C.