The role and preparation of melamine

Melamine pictures Image: Melamine structural formula Melamine (Melamine), also known as melamine, is a metabolite of cyclopromazine, used in the synthesis of melamine resin and plastic materials intermediates, according to the source network data, its molecular formula is C3H6N6, its molecular weight is 126.12, usually a white single crystal, can chemically react with strong acids and bases, soluble in water and ethanol, but the solubility is relatively low, (room temperature water solubility is 3.1 g/L), insoluble in ether, carbon tetrachloride, benzene, can be sublimated after heating, when heated sharply, it will decompose, cannot burn, and the toxicity is very low, but at high temperatures, cyanide may decompose, so it is necessary to avoid high temperatures when storing. Melamine can be used to produce melamine resin, which can be obtained by condensation polymerization with formaldehyde. It can be used in the plastics and coating industries, and can also be used as a textile material anti-pleating and anti-shrinkage treatment agent. Melamine resin can be used as a metal coating with bright color, durability and good hardness. It is also often used in the production of catering utensils. The texture is close to that of ceramics, but it has strong toughness and is not easy to break. It can also be used in the production of heat-resistant decorative sheets, moisture-proof paper, fixing agents or hardeners for water-proof agents, gray leather tanning agents, and adhesives for synthetic fireproof laminates. According to the chemical formula of melamine, its nitrogen content is very high, so some criminals will add it as a food additive to milk powder and other foods, which has caused the notorious Sanlu milk powder incident and endangered the physiological health of many children. Therefore, the state has issued relevant regulations: The limit value of melamine in infant formula milk powder is 1 mg/kg, and products higher than 1 mg/kg shall not be sold. The limit value of melamine in liquid milk (including raw milk), milk powder, and other formula milk powders is 2.5 mg/kg, and products higher than 2.5 mg/kg shall not be sold. 3. The limit value of melamine in other foods containing more than 15% milk is 2.5 mg/kg, and products higher than 2.5 mg/kg shall not be sold. Since resin is closely related to people's lives and can be used to make a variety of appliances, the melamine industry chain is very developed in China, and its uses are also constantly expanding and developing. For scientific research, you can try to prepare melamine yourself, or you can buy major brands of melamine reagents in Huayuan Mall and use them directly. Here is a simple preparation method of melamine - urea boiling method at atmospheric pressure. Using ammonia as a carrier and silica gel as a catalyst, urea is decomposed into cyanic acid at 380 to 400 degrees Celsius, and melamine gas is obtained after further condensation 108-78-1 preparation 2. Melamine gas is cooled and collected to obtain a crude product, which is then dissolved in turn to remove impurities, recrystallize, and finally obtain a finished product. 108-78-1 preparation