反应详情

温度

2.5 °C

4-Bromo-3-methylanisole (500 g, 2.5 moles) was cautiously added dropwise over a period of 20-25 minutes to 98% sulfuric acid (1,600 ml) at ambient temperature (exothermic, temperature rise to 42-43° C.) and the reaction stirred for 16 hours. The reaction mixture was cautiously quenched onto cooled (0-5° C.) deionised water (7.5 liter) over a 2 hour period at a rate that maintained the temperature below 20° C. The precipitated product was granulated for 3 hours, filtered and dried to give the crude sulphonic acid (980 g). The crude product was recrystallised from ethyl acetate (2.94 liters, 3 ml/g) to give the subtitle compound (680 g, 86% yield) as a white crystalline solid (mp=131-133° C.)

1. customThe reaction mixture was cautiously quenched
2. temperaturemaintained the temperature below 20° C
3. waitThe precipitated product was granulated for 3 hours
4. filtrationfiltered
5. customdried
6. customto give the crude sulphonic acid (980 g)
7. customThe crude product was recrystallised from ethyl acetate (2.94 liters, 3 ml/g)