Study On Synthesis Of Benzoylformic Acid And Its Esters

Benzoylformic acid and its esters are important intermediates in the manufacture of Pharmaceuticals. The synthesis of ethyl benzoylformate via oxalylation of benzene and Potassium Permanganate oxidation of styrene were studied in this paper. The influencing factors of the reaction and the possible mechanisms of the reactions were discussed.Ethyl dichloro(ethoxy)acetate was prepared via distillation of the reaction mixture of diethyl oxalate and phosphorus pentachloride at 115 ℃ for 9 hours and its purity was determined by GC normalization method to be 97%, which was 17% higher than the literature reported value of 80%. Reaction of ethyl dichloro(ethoxy)acetate with benzene in CH2Cl2 in the presence of 2 mole equivalent of AlCl3 at 0℃ for about 6 to 9 hours gave ethyl benzoylformate in 79.86% yield compared with the literature yield of 20%. The structure and composition of 'the product was characterized by GC-MS and NMR spectroscopy. It was found that ethyl p-ethylbenzoylformate was present in the product in addition to the normal oxalylation product ethyl benzoylformate. The reaction mechanism and reaction factors were discussed.Potassium permanganate was added to a mixture of styrene, sodium hydroxide solution and water in the presence of phase transfer catalyst CTAB at 55℃. The resultant mixture was allowed to react for 5 min and benzoylformic acid was obtained in 72% yield. The mole ratio of Styrene: NaOH: KMnO4 : CTAB was 1 : 15. 6 : 2. 6 : 0. 05. The kinetics and mechanism for PTC reaction were discussed.Benzoylformic acid was also obtained in 63% via oxidation of styrene emulsion in water with potassium permanganate. In the same time the reaction gave 27% of by-product, benzoic acid.Ethyl benzoylformate was synthesized from benzoylformic acid and ethanol using SO42~/TiO2 as a catalyst. The formation of the acidic center and the loss of activity of the solid superacid catalyst were analyzed.