1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-01-02 to 2009-02-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP 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:

yes (incl. QA statement)

Type of method:

effusion method: by loss of weight or by trapping vaporisate

Temp.:

ca. 20 °C

Vapour pressure:

ca. 0 Pa

Remarks on result:

other: Calculated from the regression equation

Temp.:

ca. 25 °C

Vapour pressure:

ca. 0 Pa

Remarks on result:

other: Calculated from the regression equation

Findings and Results

The vapour pressure of 1,2,4-Benzenetricarboxylic acid, decyl octyl ester (CAS No 67989 -23 -5) / 1,2,4 -Benzenetricarboxylic acid, mixed decyl and octyl triesters (CAS No 90218 -76 -1) was determined following EU A.4 using the effusion method (weight loss)

Two runs were performed.

In the first run with seven experiments, vapour pressure was determined at seven different temperatures. At lower temperatures no weight loss was detected. At the temperaures 125 and 140 °C (nominal), weight loss was found, but it was badly reproducible. It was suspected that other test items wich hat shown weight loss at lower temperatures might have influenced the result by contaminating the Knudsen cells. Therefore, it was decided to repeat the experiment.

In the second run with two experimens, vapour pressure was determined at the nominal temperatures 125 °C and 140 °C only. Significant and better reproducible weight loss was found. As higher temperatures could not be measured due to the limits of the test system and lower temperatures would not yield significant weight loss, regression was performed over these two temperatures.

The following values were determined experimentally:

Vapour Pressures (Effusion Method)

Experiment	T	P	Stand. Dev. P	RSD P
No.	K	Pa	Pa	%
1	389.3	3.79E-04	1.59E-04	41.8%
2	403.5	9.47E-04	2.67E-04	28.2%

In this table, E-04 represents multiplication with 10 ^-4.

Evaluation

Vapour pressures at 20 °C and 25 °C were calculated from the regression equation with:

Vapour pressure at 20 °C: 7.50 * 10 ^-8 Pa

Vapour pressure at 25 °C: 1.34 * 10 ^-7 Pa

Both experiments showed medium repeatability within the four replicates. Both values lie below the threshold of 10 ^-5 Pa.

Discussion

All measured values show medium reproducibility: relative standard deviation was approx. 30 - 40%: This is attributed to the low vapour pressure as well as to the composition of the test item (mixture). The calculated value for the vapour pressure at 20°C using the estimation by the software EpiWin is almost the same as the value which was determined using the regression linear. Both values lie below the threshold of 10 ^-5 Pa.

No significant impact on the assessment of the test item's behaviour in the environment is expected from the remaining uncertainty in vapour pressure.

The result of the test is considered valid.

Conclusions:

The vapour pressure of 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters is determined to be ca. 0.000000134 Pa at 25 °C

Executive summary:

The substance was measured by OECD Guideline 104 and EU Method A4. The vapour pressure of 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters is determined to be ca. 0.000000134 Pa at 25 °C.

Description of key information

The vapour pressure of 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters is 7.5 x 10^-8 Pa at 20 °C, resp. 1.34 x 10^-7 Pa at 25 °C, measured by effusion method (weight loss). The results were calculated from the regression equation.

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C