Melamine and Guanamines

Abstract

The article contains sections titled: 1. Introduction 2. Physical Properties 3. Chemical Properties 3.1. Thermal Behavior 3.2. Hydrolysis 3.3. Salt Formation 3.4. Reaction with Aldehydes 4. Production 4.1. Low‐Pressure Processes 4.1.1. BASF Process 4.1.2. Chemie Linz Process 4.1.3. Stamicarbon Process 4.2. High‐Pressure Processes 4.2.1. Melamine Chemicals Process 4.2.2. Montedison (Ausind) Process 4.2.3. Nissan Process 5. Quality Specifications 6. Chemical Analysis 7. Storage and Transportation 8. Uses 9. Economic Aspects 10. Toxicology 11. Guanamines 11.1. Production 11.2. Uses 11.3. Toxicology Melamines (2,4,6‐triamino‐1,3,5‐triazines) are produced from urea. They are used in the fabrication of melamine – formaldehyde resins for laminating and adhesive applications. Melanine is used as cross‐linker in heat‐cured and high‐solids paint systems. Guanamines (2,4‐diamino‐1,3,5‐triazines) are produced from dicyandiamide and the corresponding nitrile by base‐catalyzed cyclocondensation. They are used in similar polymer applications as for melamine. They give a lower cross‐link density and higher flexibility because only two amino functionalities are present.

Thermal deprotonation and condensation of melamine in the presence of indium(iii)chloride

“…The new compound (NH 4 )[(InCl 2 ) 3 (C 12 N 20 H 8 )]• 2 3 [InCl 3 (NH 3 )] and the hitherto unknown side-phases of (NH 4 ) 2 [InCl 5 (NH 3 )], and (NH 4 ) 3 InCl 6 are obtained on heating equimolar amounts of indium(III) chloride and melamine at 250 °C. The inner nitrogen (1) atoms of melam (shown in Scheme 1a) form con-nections with an indium atom in the center of the ring-shaped molecule (Scheme 1b).…”

“…1 Commercial manufacture of urea increased its widespread availability. [2][3][4] Later, in the early twentieth century, the recognition of its properties, particularly its thermal stability, contributed to a better understanding of the compound. Although Liebig and Gmelin 1,5 initially proposed the condensation product of melamine, known as heptazine compounds, only elemental analysis was performed during that period.…”

A Study on Byproducts in the High-Pressure Melamine Production Process

“…Melamine (cyanuramide, 2,4,6-triamino-1,3,5-triazine) is a substance that has been known since 1834 [1][2][3][4] when Justus von Liebig first obtained the product in the reaction of potassium thiocyanate with ammonium chloride. In 1940, it was proposed that melamine could be obtained from urea, and in 1963, a high-pressure method for melamine production was implemented.…”

“…The melamine obtained from urea using high-pressure technology is characterized by the high purity of the final product. The reaction is carried out at a pressure of approximately 8 MPa and a temperature of approximately 400 • C and proceeds according to the following equation [3]:…”

Effects of a 28-day dietary co-exposure to melamine and cyanuric acid on the levels of serum microRNAs in male and female Fisher 344 rats

“…Melamine is commonly used in the manufacture of laminates, houseware items, and flame retardants (Crews et al , 2006), while cyanuric acid is used as a chlorine stabilizer in swimming pool water and to prepare herbicides and dyes (Huthmacher and Most, 2003). Individually, MEL&CYA exhibit low toxicity (Choi et al , 2010; Jacob et al , 2011); however, the combined exposure to MEL&CYA results in the formation of melamine cyanurate crystals that can obstruct the nephron tubules and result in acute kidney injury (Dobson et al , 2008; Puschner et al , 2007).…”