N-[2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diallylamino)-4-methoxyphenyl]acetamide

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 2017-02-15 to 2017-02-22

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: by loss of weight or by trapping vaporisate

Key result

Test no.:

#1

Temp.:

20 °C

Vapour pressure:

< 0.001 Pa

 Individual results

Vapour pressure balance

The vapour pressure was measured in the temperature range of 50 °C to 100 °C. The derived vapour pressures at the corresponding temperatures are listed in Table 1.

Table1: Measured vapour pressures and corresponding temperatures

Temperature / °C	Vapour pressure / hPa
50	7.2 × 10^-6
60	1.4 × 10^-5
70	2.2 × 10^-5
80	2.7 × 10^-5
90	3.2 × 10^-5
100	3.0 × 10^-5

 

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.

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 similar substances (e.g. see report 20160366.03) have been estimated to be in the range of -2000. Thus, for a conservative estimation of the vapour pressure of the test item at 20, 25 and 50 °C, a value of -2000 for constant B and a value of 273.15 for constant C, respectively, were used.

The data point of the second measurement which showed the highest vapour pressure was used as the starting point for the calculation. The measured vapour pressure at 90 °C was 3.2 × 10 ^-5 hPa.

Based on this assumption, the constant A of the Antoine equation was calculated.

Subsequently, the vapour pressure at 20, 25 and 50 °C can be calculated with the Antoine equation as follows:

Table2: Calculated vapour pressure at 20, 25 and 50 °C

T / °C	p / hPa	p / Pa
20	< 1.6×10^-6	< 1.6×10^-4
25	< 2.0×10^-6	< 2.0×10^-4
50	< 6.7×10^-6	< 6.7×10^-4

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

Table3: Final upper limit values for the vapour pressure at 20, 25 and 50 °C

T / °C	p / hPa	p / Pa
20	< 1×10^-5	< 1×10^-3
25	< 1×10^-5	< 1×10^-3
50	< 1×10^-5	< 1×10^-3

Conclusions:

The vapour pressure of the test substance was determined to be < 0.001 Pa at 20 °C.

Executive summary:

The following vapour pressure values for the test item were extrapolated from the experimental data:

Based on the measured vapour pressure at 90 °C, the following upper limit vapour pressure values for the test item were calculated:

 

T / °C	p / hPa	p / Pa
20	< 1×10^-5	< 1×10^-3
25	< 1×10^-5	< 1×10^-3
50	< 1× 10^-5	< 1× 10^-3

 

Description of key information

The following vapour pressure values for the test item were extrapolated from the experimental data.

Based on the measured vapour pressure at 90 °C, the following upper limit vapour pressure values for the test item were calculated:

 

T / °C	p / hPa	p / Pa
20	< 1×10^-5	< 1×10^-3
25	< 1×10^-5	< 1×10^-3
50	< 1× 10^-5	< 1× 10^-3

Key value for chemical safety assessment

Vapour pressure:

0 hPa

at the temperature of:

50 °C