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Vapour pressure

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Reference
Endpoint:
vapour pressure
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Well conducted study, under Internal management system, with good reasons not according to OECD or EU guidelines, but according to ASTM E1782-08, Standard test method for determining vapour pressure by Thermal Analysis, 2008, certificate of analysis included in the report.
Qualifier:
according to
Guideline:
other: ASTM E1782-08, Standard test method for determining vapour pressure by Thermal Analysis, 2008
Deviations:
no
Principles of method if other than guideline:
This ASTM test method is not included into EC Regulation 761/2009, Guideline A.4 Vapour pressure , nor into OECD Guideline 104 Vapour pressure. Nevertheless, this method was taken, because for substances which are thermally unstable and contain impurities it is a more suitable method than the other methods listed in the above-mentioned guidelines. It is expected that this method will be included into EC Guideline A.4 in the near future. A request for inclusion was sent to the Dutch National Coordinator for EC Test Methods recently.
GLP compliance:
no
Remarks:
Internal management system
Type of method:
other: Differential Scanning Calorimetry (DSC)
Temp.:
20 °C
Vapour pressure:
0.009 Pa
Remarks on result:
other: estimated from the Antoine equation

Six measurements at different pressures were carried out with the test substance. The intakes, the measured boiling temperatures and their corresponding observed pressures are listed in the table below.

 

Measurement

Intake

[mg]

Observed pressure

[kPa]

Boiling temperature

[°C]

1

16.36

0.051

67.6

2

16.42

0.100

75.1

3

14.91

0.152

80.9

4

17.50

0.200

84.9

5

15.26

0.300

91.1

6

17.57

0.500

100.1

 

The p,T-diagram of the individual measurements is shown in the attachment.

The Antoine equation constants A, B and C are calculated from this fit. This results in the following Antoine equation:

10log p(kPa)= 2.666 -{386.61/[T(K)-243.02]}

The estimated vapour pressure of the test substance at 20°C calculated from this equation is 8.99.10-6kPa.

This is the same as 0.009Pa.

 

Conclusions:
The estimated vapour pressure of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide at 20°C is 0.009 Pa.
Executive summary:

The vapour pressure of Di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide was determined according to ASTM E1782-08. This method is not included into EC Regulation No 761/2009, Guideline A.4, but it is expected that this will occur in the near future. Recently a request for inclusion was sent to the Dutch National Coordinator for EC Test Methods.

The estimated vapour pressure of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide at 20°C is 0.009 Pa.

Description of key information

The estimated vapour pressure of di-tert-butyl 3,3,5-trimethylcyclohexylidene diperoxide  at 20°C is 0.009 Pa.

Key value for chemical safety assessment

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

Additional information