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Physical & Chemical properties

Vapour pressure

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Reference
Endpoint:
vapour pressure
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Summary of previous measured data, information on purity is given.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Equipment:
In the first method, the DSC (Differential Scanning Calorimeter) is applied. The vacuum DSC experiments were carried out at various controlled pressure levels. Pressure is measured accurately with an electronic micro membrane manometer.
Procedure:
Approximately 15 mg is weighed into a 70 micro litre aluminium cup with a pierced lid.
After reaching a constant pre-set pressure, the DSC temperature scan is started. The heating rate is 5°C/min. During this scan, the product will evaporate. A sudden increase in the endothermic heat flow is obtained at the initial boiling point of the mixture at the pre-set pressure. A condenser, cooled by CO2 ice, captures the gases. After at least 4 DSC scans at different pressures, a plot is constructed with 10log P (P in mBar) versus 1/T (T in K), the Antoine plot of the product.
GLP compliance:
no
Type of method:
other: DSC
Key result
Temp.:
20 °C
Vapour pressure:
0 hPa
Remarks on result:
other: calculated by extrapolation of test data
Temp.:
72 °C
Vapour pressure:
0.6 mBar
Temp.:
94 °C
Vapour pressure:
3 mBar
Temp.:
40 °C
Vapour pressure:
0.01 mBar
Remarks on result:
other: 0.96 Pa

The results of the Antoine fit:

Where P                    is the vapor pressure in mBar

           A, B and C      are constants

           T                     is the absolute temperature in Kelvin.

 

Pressure and temperature can be calculated using the following equations:

 

P (mBar)       =10{A - B/(C+T(°C)+273.15)}

T (°C)             = {B / (A-10log P)} -C -273.15

Example for Trigonox C: calculation of the vapor pressure at 75°C

 

P        =10{3.38 - 339.5 / (-250.25+75+273.15)}                       = 0.82 mBar

 

Example for Trigonox C: calculation of the vapor pressure at 40°C

 

P        =10{3.38 - 339.5 / (-250.25 +40+273.15)}                       = 0.009606 mBar

 

Conclusions:
The vapour pressure of tert-butyl peroxybenzoate is 0.003 Pa at 20°C.
Executive summary:

Based on results in this report and extrapolation:

The vapour pressure of tert-butyl peroxybenzoate is 0.003 Pa at 20°C.

Description of key information

The vapour pressure  of  tert-butyl peroxybenzoate is 0.003 Pa at 20°C.

Key value for chemical safety assessment

Vapour pressure:
0.003 Pa
at the temperature of:
20 °C

Additional information