反应详情

温度

0 °C

16.52 g [75 mmol] of 4-tert-butyl-2,6-dimethylphenylacetic acid and 100 ml of toluene are initially charged in a 250 ml autoclave. After cooling to 0° C., 40 ml of HF are added and the autoclave is closed. The reaction mixture is then stirred at 38-40° C. for 4 hours. Toluene and HF are then distilled off at 20° C./100 mbar. The residue is diluted with 65 ml of water and, with ice-cooling, made alkaline using 100 ml of 10% strength aqueous sodium hydroxide solution. The solution is extracted once with 65 ml of MTBE and once with 35 ml of MTBE, the aqueous phase is then, with ice-cooling, adjusted to pH 1 using 32% strength hydrochloric acid, then precipitate formed is dissolved in 130 ml of methylene chloride, the organic phase is dried and the solvent is removed under reduced pressure. This gives 11.91 g of a white solid which, according to GC(sil.), comprises 95.8% of 2,6-dimethylphenylacetic acid (92.6% of theory).

1. addition40 ml of HF are added
2. customthe autoclave is closed
3. distillationToluene and HF are then distilled off at 20° C./100 mbar
4. additionThe residue is diluted with 65 ml of water and, with ice-
5. temperaturecooling
6. extractionThe solution is extracted once with 65 ml of MTBE and once with 35 ml of MTBE
7. temperaturewith ice-cooling
8. customprecipitate
9. customformed
10. customthe organic phase is dried
11. customthe solvent is removed under reduced pressure