反应详情

温度

100 °C

A mixture of 47.2 g of 4-tert-butyl-2,6-dimethylmandelic acid [0.2 mol], 7 g of 37% strength hydrochloric acid, 9.3 g of red phosphorus and 33 g of KI in 150 ml of glacial acetic acid is heated at 100° C. for 16 hours. The excess of phosphorus is filtered off with suction and washed three times with in each case 70 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 stirred in 180 ml of water and, by addition of about 215 g of 10% strength aqueous sodium hydroxide solution, dissolved. This solution is extracted twice with in each case 150 ml of methyl tert-butyl ether (MTBE) and then adjusted to pH 1 using 48% strength sulfuric acid. The precipitated solid is filtered off with suction, washed four times with in each case 50 ml of water and dried. This gives 37.2 g of 4-tert-butyl-2,6-dimethylphenylacetic acid in a purity of 99.1 GC area % (yield about 83.6% of theory).

1. filtrationThe excess of phosphorus is filtered off with suction
2. washwashed three times with in each case 70 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. dissolutiondissolved
5. extractionThis solution is extracted twice with in each case 150 ml of methyl tert-butyl ether (MTBE)
6. filtrationThe precipitated solid is filtered off with suction
7. washwashed four times with in each case 50 ml of water
8. customdried