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Physical & Chemical properties

Vapour pressure

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Description of key information

The vapour pressure of the lowest homologue of the substance

(3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate homopolymer, isocyanurate type, (n=3) 2-butanone oxime-blocked was calculated to be 1.3E-23 Pa at 25 °C.

Key value for chemical safety assessment

Vapour pressure:
0 Pa
at the temperature of:
25 °C

Additional information

Two reliable results are availabe, one from an experimental study and one QSAR which are evaluated in a weight-of-evidence approach.. The experimental result is based on a study using the Knudsen effusion method (mass-loss technique), according to the guidelines OECD 104 / EU A.4.

The vapour pressure was found to be 9.9 x 10-5 Pa at 20 °C (1.5 x 10-4 Pa at 25 °C). However this result was evaluated to be questionable although the procedure followed exactly the guideline. It was thought that a substance with a molecular weight of 928 and higher should have a much lower vapour pressure.

The substance is only produced and marketed in solution. The solvent can be removed without changing the identity of the substance. However for the measurement of the vapour pressure it is essential to remove also any traces of remaining solvent as those have a strong effect on the outcome. It is thought that this is the case in this example.

Therefore a QSAR was generated using the MPBPVP method of EPISUITE. The result of 1.3E-23Pa at 25 °C differs extremely from the measured result but was evaluated to be more reliable.