| 摘要 |
The invention provides a novel method for the preparation of guanidine sulfamate from the reaction mixture of urea and an ammonium aqua-ammonosulfate, e.g. ammonium imidosulfonate, obtained by the reaction under atmospheric pressure followed by hydrolysis with water. Different from conventional procedures, the hydrolysis in the inventive method is carried out at a temperature not exceeding 100 DEG C. or, preferably, at about 70 DEG C., in which the retardation of the reaction velocity at the lower temperature is compensated for by admixing the aqueous solution of the reaction mixture with a portion of the hydrolysis product obtained in the preceding run. After completion of the hydrolysis reaction, the hydrolysis product is admixed with calcium hydroxide or oxide and the desired guanidine sulfamate is obtained from the liquid portion from which the excess of the calcium ions has been removed.
|
