Hydrogen Peroxide → 5-Bromovanillin

Participants

Reaction Conditions

Reaction Steps

Anhydrous acetic acid (20 ml) followed by vanillin (7.5 g; 0.05 mole) were charged into a 100-ml round glass flask equipped with a stirring system, thermometer, a dropping funnel and cooled with a water bath at 20° C. Stirring was begun and then, when the vanillin had dissolved, a solution of bromine (4.8 g; 0.03 mole) in acetic acid (10 ml) was added dropwise. The temperature gradually increased to 30° C. When the bromine addition was complete, acetic acid (20 ml) was added, followed, dropwise, by hydrogen peroxide at a concentration of 30% of H2O2 (2.26 g; 0.02 mole). Stirring was continued for 10 min upon completion of the addition and the heterogeneous reaction mixture was cooled to 20° C. It was next filtered and the cake was washed on the filter with fresh acetic acid (10 ml) followed by ice water (30 ml). After drying under vacuum, a product (10.8 g) melting at 162 ° C. was obtained, in which 5-bromovanillin (10.60 g) was determined by high pressure liquid chromatography. Unconverted vanillin (0.45 g) was determined in the filtrate and the acetic acid wash.

Provenance & Evidence