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-tetrafluorobenzoyl-malonate in 300 ml of water. The mixture is heated at the boiling point for 4.5 hours, with thorough stirring, the cooled emulsion is extracted several times with methylene chloride, the combined methylene chloride solutions are washed once with saturated sodium chloride solution and dried with sodium sulphate and the solvent is distilled off in vacuo. Fractionation of the residue under a fine vacuum gives 160.2 g of ethyl 2,3,4,5-tetrafluorobenzoylacetate of boiling point 75°-96° C./0.06-0.09 mbar.

1. temperatureThe mixture is heated at the boiling point for 4.5 hours, with thorough stirring
2. extractionthe cooled emulsion is extracted several times with methylene chloride
3. washthe combined methylene chloride solutions are washed once with saturated sodium chloride solution
4. dry with materialdried with sodium sulphate
5. distillationthe solvent is distilled off in vacuo