反应详情

温度

55 °C

8.9 kg of 5-bromo-2,4-dihydroxybenzoic acid are dissolved in 70 l of methanol and heated to 55° C. 800 ml of sulfuric acid (w=95-98%) are subsequently metered in, and the mixture is stirred under gentle reflux for 4 days, during which a further 500 ml of sulfuric acid (w=95-98%) were added daily (3 times). The reaction mixture is stirred into a cooled solution (5° C.) of 9 kg of sodium hydrogencarbonate in 100 l of water. Filtration and drying in vacuo at 50° C. gives 7.87 kg (83%) of methyl 5-bromo-2,4-dihydroxybenzoate (white crystals), MW 247.1.

1. additionwere added daily (3 times)
2. filtrationFiltration
3. customdrying in vacuo at 50° C.