Reaction products of 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid, coupled twice with diazotized 2-[(4-aminophenyl)sulfonyl]ethyl hydrogen sulfate, sodium salts

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

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

Qualifier:

according to guideline

Guideline:

other: OECD 113 (1981) - Screening test for thermal stability and stability in air

Deviations:

no

GLP compliance:

no

Type of method:

effusion method: vapour pressure balance

Key result

Temp.:

20 °C

Vapour pressure:

< 0 hPa

Remarks on result:

other: The vapour pressure values were calculated as conservative estimates, based on a lack of any detectable vapour pressure of the test item up to 138.8 °C and the detection limit of the method, i.e. 10E-5 hPa

Temp.:

50 °C

Vapour pressure:

< 0 hPa

Remarks on result:

other: The vapour pressure values were calculated as conservative estimates, based on a lack of any detectable vapour pressure of the test item up to 138.8 °C and the detection limit of the method, i.e. 10E-5 hPa

Transition / decomposition:

yes

Transition temp.:

>= 150 °C

Thermal Stability

The DSC-measurement in a closed glass crucible showed an exothermal decomposition in the temperature range of 150 - 230 °C (double peak) with an energy of approx. 300 J/g.

Vapour Pressure Balance (Effusion Method)

The vapour pressure was measured in the temperature range of 23 °C to 139 °C. Due to the fact that the exothermal decomposition starts at 150 °C the maximum test temperature was limited to 140 °C.

No vapour pressure of the test item above the lower detection limit of 10^-5 hPa was observed in the entire range. The vapour pressure was measured at the following temperatures: 23.2, 47.8, 59.4, 66.6, 73.4, 84.8, 96.6, 108.9, 125.2, 137.3, and 138.8 °C. For every temperature the vapour pressure of the test item was <10^-5 hPa.

Estimation of the vapour pressure for the test item at 20, 25 and 50 °C

According to the Antoine equation, the vapour pressure can be calculated according to:

Log p = A + B / (273.15 +T)               p in hPa and T in °C

Values for the slope of the Antoine equation (constant B) for comparable substances, which can be found in the literature (e.g. Handbook of Chemistry and Physics) are normally lower than - 5000. Thus, for a conservative estimation of the vapour pressure of the test item at 20, 25 and 50 °C, a slope (constant B) of -5000 was used.

The last data point of the measurement at 138.8 °C was used as the starting point for the calculation. The measured vapour pressure at 138.8 °C was below 10^-5 hPa. For a conservative estimation, it was assumed that the vapour pressure at 138.8 °C corresponds to the lower detection limit of the vapour pressure balance, i.e. 10^-5hPa.

Based on this assumption, the constant A of the Antoine equation was calculated according to A = log p - [B / (273.15 + T)] = log 10^-5- [- 5000 / (273.15 + 150.2)]= 7.1315

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

Log p = 7.1315 - 5000 / (273.15 +T)                        p in hPa and T in °C

T in °C	p in hPa	p in Pa
20	1.19x 10^-10	1.19x 10^8
25	2.30 x 10^-10	2.30 x 10^-9
50	4.56 x 10^-9	4.56 x 10^-7

 

This is a conservative estimation of the vapour pressure of the test item for the listed temperatures. Since the true vapour pressure is most likely to be even much lower than this value derived from the detection limit, it may safely be assumed that the vapour pressure at the above listed temperatures is far below 10^-7 hPa (10^-5 Pa).

Conclusions:

The vapour pressure of test item was found to be <10E-5 hPa at 20 °C temperature.

Executive summary:

Thermal Stability

The DSC-measurement in a closed glass crucible showed an exothermal decomposition in the temperature range of 150– 230 °C (double peak) with an energy of approx. 300 J/g.

 

Vapour Pressure Balance (Effusion Method)

The vapour pressure was measured in the temperature range of 23°C to 139°C. Due to the fact that the exothermal decomposition starts at 150°C the maximum test temperature was limited to 140 °C.

No vapour pressure of the test item above the lower detection limit of 10 ^- 5 hPa was observed in the entire range. The vapour pressure was measured at the following temperatures: 23.2, 47.8, 59.4, 66.6, 73.4, 84.8, 96.6, 108.9, 125.2, 137.3, and 138.8 °C. For every temperature the vapour pressure of the test item was <10^-5 hPa.

The following vapour pressure values were calculated as conservative estimates, based on a lack of any detectable vapour pressure of the test item up to 138.8 °C, and the detection limit of the method, i.e.10^-5hPa:

 

T in °C	p in hPa	p in Pa
20	<< 1.0 · 10^- 7 hPa	<< 1.0 · 10^- 5 Pa
25	<< 1.0 · 10^- 7 hPa	<< 1.0 · 10^- 5 Pa
50	<< 1.0 · 10^- 7 hPa	<< 1.0 · 10^- 5 Pa

 

Description of key information

The vapour pressure was measured in a temperature range of 23 °C to 139 °C. Due to the fact that the exothermal decomposition starts at 150 °C the maximum test temperature was limited to 140 °C.

No vapour pressure of the test item above the lower detection limit of 10 ^- 5 hPa was observed in the entire range. The vapour pressure was measured at the following temperatures: 23.2, 47.8, 59.4, 66.6, 73.4, 84.8, 96.6, 108.9, 125.2, 137.3, and 138.8 °C. For every temperature the vapour pressure of the test item was < 10^-5 hPa.

Key value for chemical safety assessment

Vapour pressure:

0 hPa

at the temperature of:

20 °C