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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:
May 2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well conducted study, under Internal Management System, according to OECD Guideline 104. Certificate of analysis included inthe report.
Qualifier:
according to guideline
Guideline:
EU Method A.4 (Vapour Pressure)
Version / remarks:
2009
Deviations:
yes
Remarks:
See principles of method other than guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Version / remarks:
2006
Deviations:
yes
Remarks:
See principles of method other than guideline
Principles of method if other than guideline:
The study was carried out in a TGA that uses a horizontally positioned oven instead of a vertically positioned one. This means that the sample carrier plate is in a horizontal position and the constant nitrogen flow streams from right to left. It is not expected that this deviation affects the outcome of the study, since the reference substances were measured using the same configuration.
GLP compliance:
no
Other quality assurance:
other: ISO 9001
Type of method:
effusion method: vapour pressure balance
Remarks:
Isothermal Thermo gravimetric Effusion method
Temp.:
20 °C
Vapour pressure:
0 Pa

Calibration 

The calibration was carried out one month before this study. For each reference substance the evaporation rate at 20°C, determined in this calibration, and the known vapor pressure are mentioned in the table below. The calibration curve is also shown in the attachment.

The calibration resulted in the following values:

- constant C     : 3.7224

- constant D     : 1.0527

- r2                     : 0.9976

- n                    : 5 

 

Reference substance

PT,20

[Pa]

log pT,20

vT,20

[g.cm-2.h-1]

log vT,20

Naphthalene

7.20 x 100

+ 0.857

2.51 x 10-3

- 2.601

n-octadecane

1.46 x 10-2

- 1.835

2.88 x 10-6

- 5.540

Hexachlorobenzene

1.47 x 10-3

- 2.833

7.46 x 10-7

- 6.127

Chrysene

8.40 x 10-7

- 6.076

4.38 x 10-10

- 9.358

Benzo(g,h,i)perylene

1.33 x 10-8

- 7.876

1.18 x 10-11

-10.928

 

Check of nitrogen flow rate.

 

The flow rate was within the range of 53.4 ± 0.2 ml/min.

 

Vapourpressure of test substance 

  

The evaporation rate of the test substance was measured at 25°C and 30°C:

- at 25°C          : vT= 4.43 x 10-7g.cm-2.h-1

- at 30°C          : vT= 2.56 x 10-6g.cm-2.h-1

 

The evaporation rate at 20°C can be calculated from the measured rates at 25°C and 30°C by linear extrapolation of log vTversus 1/T according to equation (2). This results in:

vT,20= 7.21 x 10-8g.cm-2.h-1.

 

The vapor pressure of the test substance at 20°C can be calculated by using equation (3).

This results in: pT,20= 1.6 x 10-4

 

Conclusions:
The vapour pressure of dilauroyl peroxide at 20°C is 0.00016 Pa.
Executive summary:

The study was conducted to determine the vapour pressure of the substance by Isothermal Thermo gravimetric Effusion method.

The vapour pressure of dilauroyl peroxide at 20°C is 1.6 x 10-4Pa.

Description of key information

The vapour pressure of dilauroyl peroxide at 20°C is 1.6 x 10-4 Pa.

Key value for chemical safety assessment

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

Additional information

This endpoint is supported by:

105-74-8, Vapour pressure, ACD labs, 2013, SS

The calculated vapour pressure of dilauroyl peroxide is 0.00000065 Torr, wihich is 0.00008666 Pa, which is very low too.