Sulfuric Acid → HCID 19107715, Verbindung

Temperatur

0 °C

16.7 g of 2-methyl-3-bromopropionic acid are dissolved in 50 ml of toluene, the solution obtained is cooled to 0° C., then 19.42 g of potassium rhodanide and 5 ml of water are added. The pH value of the reaction mixture is adjusted to 6.5 by the dropwise addition of 10 n sodium hydroxide. The pale yellow biphasic solution obtained is stirred at 25° C. for 48 hours while maintaining the pH value between 6.4 and 6.6 by adding further amounts of sodium hydroxide as required. The reaction mixture is cooled to 0° C. and adjusted to a pH value of 2.7 by adding 10 n sulfuric acid, then filtered and the organic phase is separated. The aqueous phase is extracted 5 times with 20 ml of toluene, the organic solutions are combined and extracted with 10 ml of water. The pale yellow toluene solution is dried over anhydrous magnesium sulfate and evaporated under reduced pressure to obtain 11.13 g /76.7%/ of 2-methyl-3-thiocyanatopropionic acid, m.p.: 24°-25° C. Based on determination by gas chromatography, the purity of the product is 98 to 99 per cent.

1. customthe solution obtained
2. customThe pale yellow biphasic solution obtained
3. temperaturewhile maintaining the pH value between 6.4 and 6.6
4. temperatureThe reaction mixture is cooled to 0° C.
5. filtrationfiltered
6. customthe organic phase is separated
7. extractionThe aqueous phase is extracted 5 times with 20 ml of toluene
8. extractionextracted with 10 ml of water
9. dry with materialThe pale yellow toluene solution is dried over anhydrous magnesium sulfate
10. customevaporated under reduced pressure

ORD-Eintrag

ord-5c24d1f815684bf585c47c0ff95e51c7

Quelldatensatz

uspto-grants-1994_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05276207