4-[[2-methoxy-4-[(4-nitrophenyl)azo]phenyl]azo]phenol

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From June 28, 2016 to June 30, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

no

GLP compliance:

no

Type of method:

effusion method: vapour pressure balance

Key result

Temp.:

20 °C

Vapour pressure:

< 0 Pa

Key result

Temp.:

25 °C

Vapour pressure:

< 0 Pa

Key result

Temp.:

50 °C

Vapour pressure:

< 0 Pa

Vapour pressure balance

The vapour pressure was measured in the temperature range of 50 °C to 110 °C. Since the test did not yield vapour pressures sufficiently high to extrapolate to 20, 25 and 50°C, these values were estimated. According to the Antoine equation, the vapour pressure can be calculated according to: p = Vapour pressure in hPa; T = Temperature in °C and A, B, C = Antoine constants. For an extrapolation to lower temperatures a conservative assumption of the Antoine constant C is 273.15. This results in a linear dependency of log(p) of the inverse Temperature 1/T (in K). Values for the resulting slope of the Antoine equation (constant B) for substances of high molecular weight, which can be derived from literature values are lower than -5000. Thus, for a conservative estimation of the vapour pressure of the test substance at 20, 25 and 50 °C, a value of -5000 for constant B and a value of 273.15 for constant C, respectively, were used. The last data point of the measurement at 110 °C was used as the starting point for the calculation. The measured vapour pressure at 110 °C was 1.1× 10-5hPa.

In order to further ensure a conservative approach the vapour pressures were rounded up to the next order of magnitude in order to obtain final upper limit values for the vapour pressure.

Conclusions:

Under the study conditions, the vapour pressure of the test substance was determined to be <1.0E-06, <1.0E-06, and <1.0E-05 Pa at 20, 25 and 50°C, respectively.

Executive summary:

A study was conducted to determine the vapour pressure of the test substance, according to OECD Guideline 104 and EU Method A.4. The effusion method: vapour pressure balance was used to assess this parameters. The vapour pressure was measured in the temperature range of 50 °C to 110 °C. Since the test did not yield vapour pressures sufficiently high to extrapolate to 20, 25 and 50°C, these values were estimated. According to the Antoine equation, the vapour pressure can be calculated according to: p = Vapour pressure in hPa; T = Temperature in °C and A, B, C = Antoine constants. For an extrapolation to lower temperatures a conservative assumption of the Antoine constant C is 273.15. This results in a linear dependency of log(p) of the inverse Temperature 1/T (in K). Values for the resulting slope of the Antoine equation (constant B) for substances of high molecular weight, which can be derived from literature values are lower than -5000. Thus, for a conservative estimation of the vapour pressure of the test substance at 20, 25 and 50 °C, a value of -5000 for constant B and a value of 273.15 for constant C, respectively, were used. The last data point of the measurement at 110 °C was used as the starting point for the calculation. The measured vapour pressure at 110 °C was 1.1× 10-5hPa.

In order to further ensure a conservative approach the vapour pressures were rounded up to the next order of magnitude in order to obtain final upper limit values for the vapour pressure. Under the study conditions, the vapour pressure of the test substance was determined to be <1.0E-06, <1.0E-06 and <1.05E-05 Pa at 20, 25, and 50°C, respectively (Dornhagen, 2016).

Description of key information

The vapour pressure was determined according to OECD Guideline 104 and EU Method A.4 (effusion method) (Dornhagen, 2016).

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C

Additional information

Value used for CSA:

<1.0E-06 at 25°C