| Production method | It is obtained by closed loop and sulfonation of benzoylbenzoic acid. Operation Example: 998kg of 20% fuming sulfuric acid and 574kg of 65% fuming sulfuric acid (the concentration of mixed fuming sulfuric acid is 36.5%) are added into a mercury dissolving pot, and 7.5kg of metallic mercury is added. Stir and heat to 80-90 ℃, keep the temperature for 5-6h. After the mercury is completely dissolved, it is added to the sulfonation pot and cooled to below 50 ℃. After adding mercury salt to the sulfonation pot, 790kg of benzoylbenzoic acid and 570kg of anthraquinone are added at no more than 90 ℃. Raise the temperature to 120 ℃, keep the temperature for 3 hours, sulfonate is completed, sulfonate is diluted in the previous batch of lotion, and keep the temperature at 100 ℃ for 2 hours. Filter and wash with 100 ℃ hot water to neutral. The filtrate and part of the concentrated lotion are fed into the neutralization pot; the light lotion is reserved for dilution in the next batch. The filter cake is recycled anthraquinone, dried, and used for the next batch of sulfonation. The specific operation steps are as follows: add the above filtrate into the neutralization pot, adjust the relative density of the solution to 1.075-1.085 with water and heat to 80 ℃, and neutralize with 17-20% ammonia water to a pH value of 7. Keep the temperature at 80-85 ℃ for 0.5h. Filter, wash with 60 ℃ hot water 800-1000L, blow dry, filter cake is anthraquinon-1-sulfonate ammonium salt. The total yield was 75% (based on anthraquinone). |
