2-Hydroxy-4-methoxybenzophenone-5-sulfonic acid synthesis

Yield:4065-45-6 98.82%

Reaction Conditions:

with sulfur trioxide;glacial acetic acid in 1,2-dichloro-ethane at 25; for 3 h;Inert atmosphere;

Steps:

1

400g of 1,2-dichloroethane, 100g of 2-hydroxy-4-methoxybenzophenone, and 50g of acetic acid were added to the reaction vessel, replaced with nitrogen three times, and stirred uniformly. A mixed gas of SO3 and nitrogen was introduced at a flow rate of 5 mL/min, in which the volume of SO3 was 5%. The reaction system was heated to 25°C, and after reacting for 3 hours, the reaction was stopped. To remove the excess SO3 in the reaction liquid, the reaction liquid is cooled to 20-30° C., and filtered to obtain a crude product of 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone. After washing with 1,2-dichloroethane, the crude product was re-dissolved in 400 mL of 1,2-dichloroethane at 70°C, cooled to 20°C again, crystallized and filtered to obtain The solid 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone was dried at 50°C for 4 hours to obtain 133.85 g of 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone. Benzophenone, the yield was 98.82%. The obtained 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone was re-dissolved in 1,2-dichloroethane and subjected to gas chromatography (GC) test, and the purity of the product was determined to be 99%.

References:

CN112321461,2021,A Location in patent:Paragraph 0052; 0054-0055