Add 11-12 times the amount (mass) of p-aminobenzenesulfonic acid to water at 60-65°C, then slowly add sodium carbonate to dissolve it completely, filter, cool to 0-5°C, and then add p-aminobenzenesulfonic acid 1.5 to 1.8 times the amount (mass) of hydrochloric acid, stir evenly and let it stand still to precipitate fine 1-naphthylamine-4-sulfonic acid olefin crystals, and cool to below 5°C. Slowly add 1:2 (mass) sodium nitrite solution at 3-5°C for diazotization to obtain diazonium solution. After the reaction is completed, the feed solution is strongly acidic (blue) to the Congo red test paper. Stir and dissolve 2-naphthol-6-sodium sulfonate in 20 times the amount (mass) of water at 75-80°C, then add part of sodium carbonate (1/5 of the total amount), dissolve and filter. Put the filtrate into the reaction kettle, then add the rest of the Chemicalbook sodium carbonate, stir and cool to 5-8°C; then slowly add the diazonium solution at 10-15°C and the pH value is 8-9 to carry out the coupling reaction for several hours. After the reaction is completed (2-naphthol-6,8-sodium disulfonate is slightly excessive), heat it up to 50-60°C, add refined sodium chloride, stir, let it cool down to room temperature naturally, and let it stand to precipitate crystals; Stir and dissolve the crystals in 15 times the amount (mass) of clean water at 70°C, add an appropriate amount of sodium carbonate to make the solution slightly alkaline, add refined salt after filtration, stir and adjust the pH value to 6.5-7.0 with hydrochloric acid, stand for crystallization, and separate Dried to get the finished product.
Preparation of Sunset Yellow Aluminum Lake
Prepare aluminum hydroxide from aluminum salts such as aluminum chloride and aluminum sulfate and alkalis such as sodium carbonate, then add sunset yellow aqueous solution and precipitate to obtain the product.