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Environmental fate & pathways

Hydrolysis

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Description of key information

The substance as well as the decomposition products melamine and cyanuric acid are hydrolytically stable in the aqueous environment.

Key value for chemical safety assessment

Additional information

The substance has not been tested as a study is scientifically not justified.

 

The substance is a high molecular weight complex, self-assembled via organized network of hydrogen bonds and aromatic ring stacking. The molecules of melamine and cyanuric acid are strongly bound in the crystal lattice and require considerable energy to remove them. The absence of a melting point, the high decomposition temperature and the poor solubility in any solvent is a consequence of this complexation behaviour. The substance is only defined through the solid state. In such a case, water solubility is the composition of the aqueous solution formed at equilibrium under a defined set of conditions. Due to the measurement of solubility, the composition consists of dissolved melamine and dissolved cyanuric acid. Thus, under environmental conditions and at predicted concentrations in the aqueous environment, the substance is expected to dissociate into the two components melamine and cyanuric acid. Therefore read-across it is justified from the supporting substances melamine or cyanuric acid.

 

For the component 108-80-5 (cyanuric acid):

The substance is hydrolytically stable.

 

For the component 108 -78 -1(melamine):

Melamine is hydrolyzed by mineral acid or inorganic alkali. Hydrolysis proceeds stepwise, with loss of one, two, or all three amino groups, i.e. producing ammeline, ammelide and cyanuric acid. The product spectrum varies with temperature, pH, and concentration; the final product is cyanuric acid [108-80-5]. However, there is no indication that the substance hydrolyses under conditions defined by testing guidelines.