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Environmental fate & pathways

Hydrolysis

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Description of key information

HDI oligomers, iminooxadiazindione hydrolyses immediately in water. 
As no isocyanate-functions could be detected by IR-spectroscopy and no HDI oligomers, iminooxadiazindione could be detected by HPLC-MS, a complete hydrolysis of the isocyanate groups in the test substance took place during the hydrolysis perliminary test at ambient conditions.

Key value for chemical safety assessment

Half-life for hydrolysis:
7.7 h
at the temperature of:
23 °C

Additional information

Based on analogy of the structure between HDI oligomers, iminooxadiazindione and HDI oligomers, isocyanurate a read-across approach is applied, to support the results on hydrolysis behaviour of HDI oligomers, iminooxadiazindione.

In a screening test at 50 °C the HDI Trimer was found to hydrolyse by 84 – 89 % within less than 1 hour at pH values of 4, 7, and 9.

Approximate mean half-lives far below 12 hours were estimated at any pH and environmental relevant temperatures. A hydroysis product based on the hydrolysis of the 3 Isocyanate groups to the corresponding amine functions has been proposed but has not been found.

The half-life of HDI oligomers, isocyanurate in the acetonitrile/water solution is approx. 7.7 hour at room temperature (23 °C). The concentration of HDI oligomers, isocyanurate in the acetonitrile solution without addition of water was stable within 26 hours.