Tetrasodium 4-amino-5-hydroxy-6-[[2-methoxy-5-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]azo]-3-[[4-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2,7-disulphonate

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 19, 2015 - March 21, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

GLP compliance:

no

Type of method:

effusion method: vapour pressure balance

Temp.:

20 °C

Vapour pressure:

< 0 Pa

Temp.:

25 °C

Vapour pressure:

< 0 Pa

Temp.:

50 °C

Vapour pressure:

< 0 Pa

Results:

Vapour pressure balance (effusion method)

Because of a water content of 7.2 % of the test item, the latter was conditioned in the measuring cell under vacuum at 50 °C for 10 h before starting the measurement.The vapour pressure was measured in the temperature range of 60 °C to 110 °C in intervals of 10 K. The measurements showed only vapour pressures below the detection limit of 1× 10^-5. Further indication of a low vapour pressure was a very low mass weight loss of the test item over the complete time of measurement. Most measurements could not be evaluated because of an ambiguous course of the measurement values.

As within the effusion method no vapour pressures sufficiently high to extrapolate to 20, 25 and 50 °C were received these values were estimated, according to the Antoine equation.

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 (constantB) for substances of high molecular weight, which can be derived from literature values (e.g. Handbook of Chemistry and Physics) are lower than -5000. Thus, for a conservative estimation of the vapour pressure of the test item 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 detection limit (1 × 10^-5hPa) at the highest measurement point (110 °C) was used for the calculation as all measured vapour pressures were below the detection limit.

Based on this assumption, the constant A of the Antoine equation was calculated and subsequently, the vapour pressure at 20, 25 and 50 °C was calculated.

Table1: Calculated vapour pressure at 20, 25 and 50 °C

T / °C	p / hPa	p / Pa
20	< 9.9×10^-10	< 9.9×10^-8
25	< 1.9×10^-9	< 1.9×10^-7
50	< 3.8× 10^-8	< 3.8× 10^-6

 

This is a conservative estimation of the vapour pressure of the test item for the listed temperatures.

Conclusions:

The measured vapour pressures of the test item up to 110 °C were below the lower detection limit of the vapour pressure balance of 10E-5 hPa

Executive summary:

 

Final results

The measured vapour pressures of the test item up to 110 °C were below the lower detection limit of the vapour pressure balance of 10^-5 hPa. Therefore, the detection limit (1 × 10^-5hPa) at the highest measurement point (110 °C) was chosen as the basis for a conservative estimation of the following upper limit values for the vapour pressure of the test item:

 

T / °C	p / hPa	p / Pa
20	< 9.9×10^-10	< 9.9×10^-8
25	< 1.9×10^-9	< 1.9×10^-7
50	< 3.8× 10^-8	< 3.8× 10^-6

 

Description of key information

Vapour pressure 0.0000038 Pa at 50 °C

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

50 °C

Additional information

The measured vapour pressures of the test item up to 110 °C were below the lower detection limit of the vapour pressure balance of 10^-5 hPa. Therefore, the detection limit (1 × 10^-5hPa) at the highest measurement point (110 °C) was chosen as the basis for a conservative estimation of the following upper limit values for the vapour pressure of the test item:

T / °C	p / hPa	p / Pa
20	< 9.9×10^-10	< 9.9×10^-8
25	< 1.9×10^-9	< 1.9×10^-7
50	< 3.8× 10^-8	< 3.8× 10^-6