Preparation of sulfanilamide, vinegar liver, concentrated hydrochloric acid, silicone oil and PH test paper Sulfanilamide in a 100 mL three-necked bottle equipped with a stirring bar and thermometer, add sulfanilamide 17.2 g and 22.5% sodium hydroxide 22 mL, start stirring, and heat to about 50℃ in a water bath. After sulfanilamide was dissolved, acetic anhydride 13.6 mL and 77% sodium hydroxide 12.5 mL were added in stages (acetic anhydride 3.6 mL and 77% sodium hydroxide 2.5 ml were added first; Be added; Subsequently, the remaining 77% sodium hydroxide and acetic anhydride were added alternately for 5 times with an interval of 5 minutes each time). The reaction temperature is kept at 50-55 DEG C during the feeding process; Keep this temperature for 30 minutes after feeding. After the reaction, stop stirring, pour the reaction solution into a 250 mL beaker, add 20 mL water to dilute it, adjust the pH to 7 with 36% hydrochloric acid in a cold water bath, let it stand for 30 min, stir it from time to time to separate the solid, and remove it by suction filtration. The filtrate was adjusted to pH 4~5 with 36% hydrochloric acid and filtered to obtain white powder. Dissolve the white powder with 3 times (3 ml/g) of 10% hydrochloric acid, stir it from time to time, try to dissolve monoacetyl into hydrochloride, and filter to remove insoluble substances. The filtrate was decolorized with a small amount of activated carbon at room temperature for 65438 00 minutes, and then filtered. The pH of the filtrate was adjusted to 5 with 40% sodium hydroxide, and acesulfame was separated, filtered and dried. Dry and measure the melting point (mp. 179~ 184℃). If the product is not up to standard, it can be refined with hot water (1:5). PH> add vinegar liver 13, ph