反应详情

0.3 g of p-toluenesulphonic acid is added to an emulsion of 284.8 g of crude diethyl 2,3,4,5-tetrafluorobenzoylmalonate in 300 ml of water. The emulsion is heated to boiling for 5 hours, stirring vigorously, then it is cooled and extracted several times with methylene chloride, and the combined methylene chloride solutions are washed once with saturated NaCl solution, dried with Na2SO4, and the solvent is removed by distillation in vacuo. Fractionation of the residue under fine vacuum provides 160.2 g of ethyl 2,3,4,5-tetrafluorobenzoylacetate of boiling point 100°-110° C./0.09-0.1 mbar. Melting point 47°-49° C.

1. temperatureThe emulsion is heated
2. temperatureit is cooled
3. extractionextracted several times with methylene chloride
4. washthe combined methylene chloride solutions are washed once with saturated NaCl solution
5. dry with materialdried with Na2SO4
6. customthe solvent is removed by distillation in vacuo