The synthetic methods
1. Sodium nitrite synthesis (oximation method) Add water to the reactor, add sodium nitrite under agitation, add sodium pyrosulfite in stages, and then acidify with sulfuric acid. The acidified material was fed into the hydrolysis kettle, acetone was added, and then neutralized with liquid alkali, and the neutralized liquid was distilled to obtain acetone oxime. Acetone oxime and hydrochloric acid were added into the salt kettle to react to form hydroxylamine hydrochloride and acetone. Acetone recovery and use; Hydroxylamine hydrochloride through concentration, cooling crystallization, centrifugal separation, drying, can be finished. Raw material consumption norm: sodium nitrite (95%)1970kg/t, sodium metabisulfite (64% SO2)5418kg/t, acetone (98%)1175kg/t. 2. Nitromethane process nitromethane interacts with hydrochloric acid and water to produce hydroxylamine hydrochloride. According to HGB3044-76, hydroxylamine hydrochloride product is white crystal, the content of grade 2 product ≥98.5, the content of grade 3 product ≥97%. Raw material consumption quota: nitromethane 1200kg/t, hydrochloric acid (30%)1500kg/t
2. Or by nitromethane and hydrochloric acid, water interaction to produce hydroxylamine hydrochloride
3. Dissolve sodium nitrite in water and cool it to 0℃; add sodium bisulfite and 35%~40% dilute sulfuric acid to make the solution pH =2; stop stirring when acetone temperature rises to 35℃; keep the temperature at 70℃ for 3 hours; cool it to 30℃; add sodium hydroxide solution to pH 7~8. The acetone oxime was steamed by heating, hydrochloric acid was added, the temperature was maintained at 55~60℃ for 12h, and then the concentration was carried out. After a little cold decolorization, filtration, reconcentration, cooling, crystallization, the finished product. The refining process can be soaked in ethanol or recrystallized in water.