Registration Dossier

Administrative data

Endpoint:
vapour pressure
Type of information:
experimental study
Adequacy of study:
key study
Study period:
March 08, 2006 to March 09, 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 104 (Vapour Pressure Curve)
Qualifier:
according to
Guideline:
EU Method A.4 (Vapour Pressure)
GLP compliance:
yes
Type of method:
effusion method: vapour pressure balance

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Specific details on test material used for the study:
Batch No.: 05.9.9
Purity: 99.56% CuSCN
Storage conditions: Ambient temperature (10-30°C), dry
Expiry date of the test item: May 20, 2007

Results and discussion

Vapour pressureopen allclose all
Temp.:
20 °C
Vapour pressure:
< 0 hPa
Remarks on result:
other: The vapour pressure was calculated as a conservative estimate, based on a lack of any detectable vapour presure of the pure test item at 152.2°C, and the detection limit of the method i.e. 1E-5 hPa.
Temp.:
25 °C
Vapour pressure:
< 0 hPa
Remarks on result:
other: The vapour pressure was calculated as a conservative estimate, based on a lack of any detectable vapour presure of the pure test item at 152.2°C, and the detection limit of the method i.e. 1E-5 hPa.
Temp.:
50 °C
Vapour pressure:
< 0 hPa
Remarks on result:
other: The vapour pressure was calculated as a conservative estimate, based on a lack of any detectable vapour presure of the pure test item at 152.2°C, and the detection limit of the method i.e. 1E-5 hPa.

Any other information on results incl. tables

Individual Results

Thermal Stability (DSC)

The DSC-measurements showed neither an endothermic effect nor an exothermal effect in the entire temperature range 25 - 400°C.

Vapour Pressure Balance (Effusion Method)

The vapour pressure was measured in the temperature range of 32 °C to 152°C. Above 115 °C a vapour pressure could be measured. The measured vapour pressures at the corresponding temperatures are listed in the following table:

 No.   

Temperature (°C)

 Vapour pressure (hPa)
 1  115.3  1.4 x 10-5
 2  116.0  1.4 x 10-5
 3  121.3  2.2 x 10-5
 4  126.7  2.2 x 10-5
 5  135.4  3.0 x 10-5
 6  144.9  3.0 x 10-5
 7  152.2  1.5 x 10-5
 8  151.6  7.5 x 10-6

Figure 2 (see IUCLID section "illustration (picture/graph)") gives the vapour pressure (logarithmic scale) as a function of the inverse temperature (1/T, T in Kelvin). Only for better readability the temperature is reported in a centigrade scale.

The vapour pressure shows an untypical course as a function of the inverse temperature. The measured vapour pressure of the test item decreases at higher temperature (the vapour pressure at constant temperature e.g. 150 °C decreases over time). This indicates that the measured vapour pressure cannot be related to the pure test item but it is caused by mass limited additives or impurities, contained in the test item. This explains the constant or decreasing vapour pressure at higher temperatures > 140 °C.

Due to this a regression cannot be performed with the measured data. But from the measurement it can be clearly derived, that the vapour pressure of the pure test item at 152.2°C is below the lower detection limit of the vapour pressure balance, i.e. 10-5 hPa. With these limits an estimation of the vapour pressure values for 20, 25 and 50 °C is performed.

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 152.2 °C was used as the starting point for the calculation. The measured vapour pressure at 152.2 °C was below 10-5 hPa. For a conservative estimation, it was assumed that the vapour pressure at 152.2 corresponds to the lower detection limit of the vapour pressure balance, i.e. 10-5 hPa.

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 + 152.2) = 6.7550

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

Log p = 6.7550 - 5000 / (273.15 +T)

p in hPa and T in °C

T in °C

 p in hPa  p in Pa
 20  5.00 x 10-11  5.00 x 10-09
 25  9.66 x 10-11  9.66 x 10-09
 50  1.92 x 10-09  1.92 x 10-07

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).

Final Results

Vapour Pressure

The following vapour pressure values were calculated as conservative estimates, based on a lack of any detectable vapour pressure of the pure test item at 152.2°C, and the detection limit of the method, i.e.10-5 hPa:

T / °C

 p / hPa  p / Pa
 20  <<1.0 x 10-7    <<1.0 x 10-5
 25   <<1.0 x 10-7    <<1.0 x 10-5
 50   <<1.0 x 10-7    <<1.0 x 10-5

Applicant's summary and conclusion

Conclusions:
The following vapour pressure values were calculated as conservative estimates, based on a lack of any detectable vapour pressure of the pure test item at 152.2°C, and the detection limit of the method, i.e.10E-5 hPa:
At 20°C, 25°C, and 50°C, the vapour pressure was, for each temperature, <<1.0E-7 hPa (<<1.0E-5 Pa).
Executive summary:

The study was conducted in accordance with the principles of GLP and internationally recognised guidelines/methods for testing vapour pressure. The vapour pressure of the test item was determined using the effusion method. At 20°C, 25°C, and 50°C, the vapour pressure was, for each temperature, <<1.0E-7 hPa (<<1.0E-5 Pa).