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Physical & Chemical properties

Vapour pressure

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Description of key information

At temperatures between 37°C to 75°C vapour pressures between 5.04 to 44.71 mBar were measured for tert-butylperoxyisobutyrate(TBPIB).

 

Key value for chemical safety assessment

Vapour pressure:
504 Pa
at the temperature of:
37 °C

Additional information

The vapour pressure of TBPIB, 75% in isododecane, was measured at various temperatures with vaccum DSC.The temperature range of the method is limited. The lower pressure limit depends on the capacity of the vacuumpump (about 0.5 mbar), the lower temperature limit of the DSC-apparatus (25°C) or by the melting point of the product.The upper limit depends on the thermal stability of the product.In the case TBPIB the lower pressure is limited by the pumpcapacity.The vapour pressure of TBPIB in the temperature range of 37°C to 75°C were measured although the temperatures were above the SADT. That was feasible in this DSC test as the amounts used were low and the measurements were very fast. At temperatures between 65°C to 77°C vapour pressure between 0.53 to 2.0 mBar were measured for tert-butyl peroxyisobutyrate (TBPIB). Extrapolation of the obtained results showed that the error in the pressure will increase at extrapolation. However, as TBPIB is used at temperatures between -5 and 0 °C a vapour pressure of 160 Pa at 20 °C was extrapolated and used for risk assessment as a worst case.