2-Phenylbenzimidazole-5-sulfonic acid synthesis

Yield:27503-81-7 98.7%

Reaction Conditions:

with sulfuric acid at 40 - 85;Reagent/catalyst;Temperature;

Steps:

2-1; 2-2; 2-3; 2-4; 2-1; 2-2 Example 2-4

Add 40 g (0.206 mol) of 2-phenylbenzimidazole to 150 g (1.53 mol) of concentrated sulfuric acid in five batches at a controlled temperature of 40 to 50 °C. After the materials are added to the mixture, the next batch of 2-Phenyl benzimidazole. After the addition was completed, the reaction mixture was heated to 85 °C and the reaction was continued until the content of 2-phenylbenzimidazole was less than 1% to complete the reaction. Then, the sulfonated solution was added to 300 g of water, and then heated to 80 °C and stirred for 1 h, and filtered to obtain 180.5 g of a filter cake. The filter cake was washed with 200 g of water, stirred at 80 ° C for 1 h, and filtered to obtain 140 g of filter cake. After vacuum drying, 55.1 g of 2-phenylbenzimidazole-5-sulfonic acid (HS) was obtained, with a content of 93.4%, and the content of 2-phenylbenzimidazole-4-sulfonic acid (isomer) was 6.25%, and the yield was 91.1 % (HS-p-phenylbenzimidazole). The reaction conditions were the same as in Example 2-2, except that the reaction system was added with 5 g of Cu-ZSM-5 catalyst, and the reaction temperature was raised to 60 °C. The ZSM-5 catalyst has a silicon-to-aluminum ratio of 100, and its preparation method is: The ZSM-5 catalyst was immersed in a 5 (weight)% potassium dihydrogen phosphate solution at 20 °C for 4h, and filtered, and the obtained solid was calcined at 500 °C for 1h at a high temperature in a muffle furnace;The ZSM-5 catalyst was further immersed in a 20 (weight)% copper sulfate solution at 20 °C for 3 hours, and filtered, and the obtained solid was dried at 110 °C for 3 hours and calcined at 550 °C for 2 hours.

References:

CN110540523,2019,A Location in patent:Paragraph 0098-0111; 0117-0120; 0124-0127