What Is Melamine?
Melamine is an organic compound with the formula C3H6N6.
It is soluble in hot water and DMSO, but not in cold water or ethanol. Melamine can also sublimate.
Melamine can be synthesized from dicyandiamide and liquid ammonia under pressure. Currently, melamine is primarily produced from urea using two main methods: a low-pressure process with a catalyst at 1-10 atmospheres and a high-pressure liquid-phase process at about 100 atmospheres without a catalyst.
Uses of Melamine
Melamine serves as a raw material for melamine resin, a thermosetting plastic made by condensing melamine with formaldehyde. This resin is favored for its water, heat, and abrasion resistance and cost-effectiveness, finding applications in tableware, sponges, paints, building materials, and textiles.
It is also utilized in manufacturing connectors, switches, and electrical components, thanks to its excellent electrical insulation and flame resistance. Additionally, melamine’s high fire and heat resistance make it a valuable flame retardant.
Properties of Melamine
Melamine is a white crystalline substance. It dissolves in about 3.2 g/100 ml of water at room temperature and is insoluble in ethanol and methanol, but soluble in ammonia and alkaline solutions.
It is thermally stable, decomposing at high temperatures (around 345°C) into ammonia, water, and carbon.
Melamine forms melamine-formaldehyde resin when reacted with aldehydes, especially formaldehyde, a common application in plastics, adhesives, and coatings production.
Generally considered non-toxic, melamine poses a risk of kidney damage if consumed in large quantities or incorporated into food or beverages.
Structure of Melamine
Melamine’s structure consists of a six-membered ring with alternating carbon and nitrogen atoms, contributing to its thermal stability and heat resistance. This structure facilitates its reactivity and cross-linking with aldehydes, essential for forming melamine-formaldehyde resin.
Other Information on Melamine
How Melamine Is Produced
Melamine production often begins with hydrogen cyanide, reacting it with ammonia to create dicyandiamide (DCDA), which is then pyrolyzed into melamine at high temperatures and pressures.
HCN + NH3 → DCDA
6DCDA → 3C3H6N6 + 6NH3
The final product, a white crystalline powder, is used to make melamine resin for various applications. While efficient, this process requires careful handling of hydrogen cyanide and consideration of its environmental impact.