Aminoguanidine Bicarbonate CAS 2582-30-1

CN200810197402 provides a preparation method of aminoguanidine bicarbonate, which solves the problems of complicated process and high cost in the existing method. The technical scheme of the present invention is realized in this way: it comprises the following steps:

1. Dissolving hydrazine hydrate in water, adding dilute sulfuric acid dropwise to obtain an aqueous solution of dihydrazine sulfate.
2. Lime nitrogen is added to the dihydrazine sulfate aqueous solution, and the pH value is adjusted to 7.2-7.8 with dilute sulfuric acid before adding the lime nitrogen.
3. After adding lime nitrogen, maintain the pH value of 7.2 to 7.8, and keep the reaction warm.
4. After the reaction is completed, it is separated by filtration, ammonium bicarbonate is added to the filtrate, crystallized, and dried by centrifugation to obtain aminoguanidine bicarbonate.

Examples are as follows:
Put 1500L tap water and 150kg hydrazine hydrate (content ≥80%) into a 3000L glass-lined reactor equipped with a pH meter online monitoring device, add 40% dilute sulfuric acid dropwise to a pH value of 5 to 6, add 1kg sodium dihydrogen phosphate Stabilizer, put in lime nitrogen in three times (the total amount of lime nitrogen is 360kg, the effective N content is ≥22%, and the lime nitrogen is 120kg each time), vigorously stir, and continuously and uniformly add dilute sulfuric acid with a flow meter. In the solution, the temperature is controlled at about 45°C with circulating water, and the solution is added dropwise until the pH of the reaction solution is 7.2 to 7.8. After the dropwise addition was completed, the temperature was increased, and the temperature was kept at 70° C. for 3 hours, and the pH of the reaction solution was maintained at 7.2 to 7.8 during the heat preservation process. Pour compressed air into the thermally insulated reaction solution for 10 minutes, and then filter the reaction solution through a centrifuge and reduced pressure vacuum; during the filtration process, rinse the filter cake with warm water at about 40°C until the filtrate is clear in color; the filtrate is concentrated Stir in a 3000L crystallization kettle, slowly and evenly add 300kg of ammonium bicarbonate, after the aminoguanidine bicarbonate crystallizes for more than 4 hours, separate by a centrifuge to obtain 376kg of wet aminoguanidine bicarbonate, content 83.6%, 40 ℃ of vacuum drying to obtain 317kg product, the content is 99.16%. The product yield calculated with hydrazine hydrate was 96.3%.