production method | add 1350ml of water and 1650ml(20mol) of concentrated hydrochloric acid with a relative density of 1.19 to a 10L glass container (or ceramic jar), cool to below 5 ℃ in an ice salt bath, add 2075g(16mol) of aniline hydrochloride 1/3 while stirring, then slowly add 1200g(17mol) of sodium nitrite and 1.5L of water newly prepared solution to start the diazotization reaction. At this time, the temperature should be maintained below 7 ℃, and the remaining aniline hydrochloride should be added from time to time. The existence of crystals can be seen in the reaction mixture at any time. After adding half of the sodium nitrite solution, add the remaining aniline hydrochloride at one time. When nitrous acid appears in the mixed solution (checked with potassium iodide-starch test paper), the reaction is immediately stopped. While the diazotization reaction is proceeding, 2150g(65mol) of 60% hydrofluoric acid is placed in another 3L beaker coated with paraffin, cooled to below 25 ℃ in a water bath, and then 100g(16.2mol) of boric acid is added in batches while shaking. Cool in an ice bath to maintain the temperature below 10°C. Under intense stirring, the formed tetrafluoroborate solution was injected into the diazonium salt solution below 0°C. Continue to stir for 20~30min, suck and filter, wash with 800ml of ice water, 800mL of methanol and 900ml of ether in turn, and filter and dry the solvent as much as possible. The light brown fluffy solid product is thinly spread on absorbent paper, placed next to the fume hood window to dry overnight, and then stored in a glass bottle. |