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Physical & Chemical properties

Vapour pressure

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Description of key information

0.0000117 Pa at 25 °C
0.00252 Pa at 70 °C

Key value for chemical safety assessment

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

Additional information

As the substance decomposes during the measurement, the determination of vapour pressure is technically not possible. Therefore an appropriate QSAR estimation method was applied for the calculation of vapour pressure at 25 °C and at 70 °C. The vapour pressures calculated at thest two temperatures are then used for the exposure assessment. The estimated values are supported by the testing results obtained from another two similar substances (CAS no. 68457-79-4 and 84605-29-8) which are with Zinc O,O,O',O'-tetrabutyl bis(phosphorodithioate) within the homologous series.

Nevertheless the vapour pressure of Zinc O,O,O',O'-tetrabutyl bis(phosphorodithioate) was experimentally determined by means of Differential Scanning Calorimetry recently.The experimental result is much less than 1 mbar at 20 °C, which is out of the recommended range of DSC measurement. Then the vapour pressure was estimated by using Grain Watson method. As the substance shows no boiling up to 155 °C and at that temperature the thermal decomposition possibly start, in the study 155 °C was used as the lowest boiling point for the calculation of vapour pressure. However this method has not been appropriately carried out because the substance decomposes before boiling, the theoretical boiling point (ca. 480 °C) estimated by MPBPWIN v1.43, is much higher than 155 °C. Therefore the study should be considered as not reliable.