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Physical & Chemical properties

Partition coefficient

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Description of key information

In accordance with column 2 of REACH Annex VII, the test cannot be performed, as the substance is hydrolytically unstable (hydrolyses immediately in water). 
The calculated partition coefficient (KOWWIN v 1.68) on the basis of the structural formula of the ideal HDI Trimer with 3 HDI (2H-1,3,5-Oxadiazine-2,4(3H)-dione, dihydro-3,5-bis(6-isocyanatohexyl)-6-[(6-isocyanatohexyl)imino]-) units is 8.38 .
By calculation the log Pow value of 8.38 for the main constituent of HDI Trimer (HDI Isocyanurate, n = 3) was calculated according to the KOWWIN program, v. 1.67 © 2000 U.S. Environmental Protection Agency. The calculated log Pow of the corresponding triamine of the main constituent (2H-1,3,5-Oxadiazine-2,4(3H)-dione, dihydro-3,5-bis(6-aminohexyl)-6-[(6-aminohexyl)imino]-) is 4.11.

Key value for chemical safety assessment

Log Kow (Log Pow):
8.38

Additional information

Read-across from structure-analogue HDI oligomers, isocyanurate:

A determination of the partition coefficient cannot be performed. In the water solubility study, the TNb-results determined are only slightly above the LOQ. As the test item and the hydrolysis products are only poorly soluble in water it is expected that after shaking with n-octanol, the residue in the aqueus phase is below the limit of quantitation of 1 mg/L. A determination of the partition coefficient is therefore not possible.The substance hydrolyses rapidly with a half life of 7.7 hours. Therefore, an experimental study with HDI trimer type is scientifically unjustified. The hydrolysis product is a complex mixture of water-insoluble oligomeric and polymeric ureas and of compounds derived from isocyanurates (n-3, 5, 7) where the isocyanate groups have been transformed to amino groups. Although being a more theoretical approach, an ideal structure the "corresponding triamine of the asym. HDI trimer (n=3)" was considered in order to get an estimation on the behaviour of the hydrolysed product. For both, the unreacted HDI Iminooxacolindione (n=3) as well as for the corresponding triamine of the sym.HDI trimer (n=3), calculated.