反应详情

温度

100 °C

A mixture of 2.89 g of 4-tert-butyl-2,6-dimethylmandelic acid and 7.75 g of 4-tert-butyl-2,6-dimethylmandelic acid acetate, 4.5 g of 37% strength hydrochloric acid, 1.86 g of red phosphorus and 0.66 g of KI in 30 ml of glacial acetic acid is heated at 100° C. for 16 hours. Excess phosphorus is filtered off with suction and washed three times with in each case 10 ml of glacial acetic acid. The filtrate is substantially concentrated on a rotary evaporator at a bath temperature of 50° C./60 mbar. The resulting residue is diluted with 25 ml of water and, by addition of 10% strength aqueous sodium hydroxide solution, dissolved. This solution is extracted twice with in each case 20 ml of MTBE and then adjusted to pH 1 using 48% strength sulfuric acid. The resulting greasy solid is taken up in methylene chloride. This solution is extracted with 25 ml of water, dried over sodium sulfate and concentrated using a rotary evaporator. This gives 7.66 g of 4-tert-butyl-2,6-dimethylphenylacetic acid in a purity of 99.0 GC area % (yield about 86% of theory).

1. filtrationExcess phosphorus is filtered off with suction
2. washwashed three times with in each case 10 ml of glacial acetic acid
3. concentrationThe filtrate is substantially concentrated on a rotary evaporator at a bath temperature of 50° C./60 mbar
4. additionThe resulting residue is diluted with 25 ml of water and, by addition of 10% strength aqueous sodium hydroxide solution
5. dissolutiondissolved
6. extractionThis solution is extracted twice with in each case 20 ml of MTBE
7. extractionThis solution is extracted with 25 ml of water
8. dry with materialdried over sodium sulfate
9. concentrationconcentrated
10. customa rotary evaporator