Monocyanamide can be seen from the molecular structure H2N-C≡N of aminocyanide, which is composed of two active groups of amino and cyano groups, and its chemical properties are very lively. And polymerization.

 

It can be seen from the hydrolysis curve and polymerization curve of the mass fraction 50% cyanamide solution at 25 ℃ that in weak acid or weak base solutions below 15 ℃, cyanamide does not undergo hydrolysis, but at 25 ℃, pH At 12 o'clock, the hydrolysis reaction is completed quickly, producing urea.

 

Like the hydrolysis reaction, the polymerization reaction of cyanamide is closely related to the acidity and temperature of the solution. When the pH is 8-10, and the temperature is greater than 40 ℃, it will rapidly polymerize into a more stable dicyandiamide, and the reaction is irreversible.
At room temperature, at pH 10, the tendency of cyanamide to hydrolyze to urea increases rapidly, while at pH> 6, the polymerization rate is significantly accelerated. Therefore, it is appropriate to control the pH of the solution at 4 to 5. When the pH is 4 ～ 5 and the temperature is controlled below 15 ℃, there is almost no hydrolysis and polymerization of cyanamide; the temperature is controlled at 20 ℃, and the mass fraction of 50% cyanamide aqueous solution increases the rate of dicyandiamide in about 3 months. . 8%, and when the temperature is controlled at 25 ～ 30 ℃, the dicyandiamide production rate will reach more than 8% within 3 months.

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