Melamine, commonly known as melamine, is a triazine nitrogen-containing heterocyclic organic compound with the chemical formula C3H6N6 and a molecular weight of 126.12 [13]. Its appearance is a white monoclinic crystal, with a melting point of about 354 ℃ (sublimation) and a density of 1.57g/cm3. Difficult to dissolve in water, ethylene glycol, glycerol, and pyridine, slightly soluble in ethanol. Melamine forms salts with acids such as hydrochloric acid, sulfuric acid, formic acid, oxalic acid, etc., and condenses with formaldehyde to form various hydroxymethyl melamine. Under slightly acidic conditions, it can condense with hydroxymethyl derivatives to form resins. Convert to cyanuric acid in water. Decompose and generate cyanamide at 600 ℃.

physical property:

Appearance: White monoclinic crystal.

Melting point: 354 ℃

Boiling point: 557.54 ℃

Flash point: 325.2 ℃

Refractive index: 1.826

Density: 1.7 ± 0.1 g/cm3

Solubility: Insoluble in water, slightly soluble in ethylene glycol, glycerol, ethanol, insoluble in ether, benzene, carbon tetrachloride

chemical property

Non flammable, stable at room temperature. The aqueous solution is weakly alkaline (pH=8) and can form melamine salts with hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, etc. In neutral or slightly alkaline conditions, it condenses with formaldehyde to form various hydroxymethyl melamine, but in slightly acidic conditions (pH=5.5-6.5), it undergoes condensation reaction with hydroxymethyl derivatives to form resins. When hydrolyzed by strong acid or strong alkali aqueous solution, the amino group is gradually replaced by hydroxyl group, first forming cyanuric acid diamide, further hydrolyzed to form cyanuric acid monoamide, and finally formed cyanuric acid.