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Triamine C16-18 and tetramine C16 -18 are surface-active substance. They consist of a hydrocarbon part which on its own would be poorly soluble in water, and a hydrophilic poly aminopropane group. The substances are strong organic bases with pKa values which range from 9 for the first amine and stepwise lower pKa’s for each next amine to be protonated.Under environmental conditions the main fraction will therefore at least be once or twice protonated. Salts with anorganic acids like sulphate, phosphate or silicate is poorly or not soluble and is not surface-active in water. Salts with organic acids like acetic acid, benzoic acid, benzoesulfonic acid and others is more soluble.

Triamine C16 -18 and tetramines C16 -18 are thus for more than 99% protonated under environmental conditions. This means that they will behave as salts in water and will have a very low vapour pressure. The solubility of these waxy cationic surface active substances will be influenced by the pH and is difficult to determine because of the surface active properties. As an alternative as suggested by the REACH guidance R.7 the CMC at pH 7 was determined. Evaporation from water is based on the low vapour pressure and the observed CMC values very unlikely. The actual dissolved concentration in water will be extremely low as the triamines C16 -18 and tetramines C16 -18 will sorb strongly to sorbents both based on hydrophobisity and ionic interaction where the ionic interaction will govern the partitioning process.

The distribution of polyamines C16-18 can be predicted assuming infinite time for equilibration using a Mackay level 1 model (MW = 440.8 g/mol; VP = 0.047 mPa; S = 40 mg/L and Log Kow = 7.285 to predict sorption). As it is in such a model is necessary to take into account the compartment of release the main fraction 97.7% is predicted to end up in soil. The remaining fraction is predicted to be found in sediment 2.4% and water 0.006%.