Fatty acids, tallow, compds. with triethanolamine

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 November 2015 to 6 September 2016

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

GLP compliance:

yes (incl. QA statement)

Type of method:

effusion method: Knudsen cell

Key result

Temp.:

20 °C

Vapour pressure:

0.001 Pa

Temp.:

25 °C

Vapour pressure:

0.001 Pa

The test was started at 15 °C, but the vapour pressure was too low to be measured experimentally at this temperature so only data at 20 °C, 63 °C, 74 °C, 85 °C and 97 °C was used for the calculation of the vapour pressure.

The vapour pressure of the test material was 0.00082 Pa at 20 °C and 0.00119 Pa at 25 °C.

Small peaks on the IR spectrum at 3342 and 3313 cm^-1 were attributable to amine groups and test material. These peaks are present in about the same proportion in the control and untested sample, confirming thermal stability over the different temperatures. These peaks gradually diminished with the higher test temperature, until at 97 °C they were almost completely absent. The remainder of the spectra remained unchanged. This would suggest the removal of triethanolamine and the active ingredient remained stable.

Table 1. Vapour PressureMeasurements

Run Number	Temp (°C)	Crucible Weight (mg)		1/T (K-1)	Vapour Pressure (Pa)		Ln (VP)
		Test 1	Test 2		Test 1	Test 2	Test 1	Test 2
2	20.0	56.279	55.681	3.41E-03	1.09E-03	1.07E-03	-6.82	-6.84
		56.273	55.675
3	20.0	56.459	56.136	3.41E-03	6.42E-04	4.95E-04	-7.35	-7.61
		56.450	56.129
4	63.0	56.352	57.026	2.97E-03	1.73E-02	1.78E-02	-4.06	-4.03
		56.280	56.956
5	74.0	55.851	56.692	2.88E-03	3.38E-02	2.30E-02	-3.39	-3.77
		55.719	56.603
6	85.0	55.260	56.493	2.79E-03	4.05E-02	4.62E-02	-3.21	-3.07
		55.106	56.316
7	97.0	57.207	55.993	2.70E-03	8.46E-03	6.24E-02	-2.47	-2.77
		56.891	55.759

Table 2: Extrapolated Vapour Pressure (VP) Results

Slope	Intercept	Correlation	Vapour Pressure (Pa)
			At 20 °C	At 25 °C
-6513.1	15.11	-0.9909	0.00082	0.00119

Note the results for Run 1 are not recorded here, because the weight loss was too low for a vapour pressure to be recorded.

Conclusions:

Under the conditions of the study, the vapour pressure of the test material was determined to be 0.00082 Pa at 20 °C and 0.00119 Pa at 25 °C.

Executive summary:

The vapour pressure of the test material was investigated in a study which was performed under GLP conditions and in accordance with the standardised guideline OECD 104.

The experimental procedure followed the Knudsen cell effusion method. Preliminary experiments were performed to assess the potential effect of more volatile components in the test material. The data suggested that there were a proportion of volatile

components which slowly diminish over prolonged testing. For substance that contain volatile components, it has been previously proven that a new samples of test substance should be taken to be used for each temperature to gives an accurate estimation of the vapour pressure. A total of 14 aliquots (7 to 9 mg) of test material were weighed into 40 µL aluminium crucibles. Lids with an orifice of a nominal 1.0 mm diameter (accurately measured), were cold welded onto each crucible and the crucibles weighed. The test temperatures used were: 15, 20 (duplicated) 63, 74, 85 and 97 °C. Two crucibles were used for each temperature. The time under vacuum was 15 to 50 minutes, when the crucible was re-weighed and a sample taken for IR analysis. A separate crucible was prepared in the same manner, except a non-perforated lid was cold welded onto it. This crucible remained in the apparatus for the all the tests to act as a control. The test was started at 15 °C, but the vapour pressure was too low to be measured experimentally at this temperature so only data at 20 °C, 63 °C, 74 °C, 85 °C and 97 °C was used for the calculation of the vapour pressure.

Under the conditions of the study, the vapour pressure of the test material was determined to be 0.00082 Pa at 20 °C and 0.00119 Pa at 25 °C.

Description of key information

Under the conditions of the study, the vapour pressure of the test material was determined to be 0.00082 Pa at °C and 0.00119 Pa at 25 °C.

Key value for chemical safety assessment

Vapour pressure:

0.001 Pa

at the temperature of:

20 °C

Additional information

The vapour pressure of the test material was investigated in a study which was performed under GLP conditions and in accordance with the standardised guideline OECD 104. The study was assigned a reliability score of 1 in accordance with the criteria for assessing data quality set forth by Klimisch et al. (1997).

The experimental procedure followed the Knudsen cell effusion method. Preliminary experiments were performed to assess the potential effect of more volatile components in the test material. The data suggested that there were a proportion of volatile

components which slowly diminish over prolonged testing. For substance that contain volatile components, it has been previously proven that a new samples of test substance should be taken to be used for each temperature to gives an accurate estimation of the vapour pressure. A total of 14 aliquots (7 to 9 mg) of test material were weighed into 40 µL aluminium crucibles. Lids with an orifice of a nominal 1.0 mm diameter (accurately measured), were cold welded onto each crucible and the crucibles weighed. The test temperatures used were: 15, 20 (duplicated) 63, 74, 85 and 97 °C. Two crucibles were used for each temperature. The time under vacuum was 15 to 50 minutes, when the crucible was re-weighed and a sample taken for IR analysis. A separate crucible was prepared in the same manner, except a non-perforated lid was cold welded onto it. This crucible remained in the apparatus for the all the tests to act as a control. The test was started at 15 °C, but the vapour pressure was too low to be measured experimentally at this temperature so only data at 20 °C, 63 °C, 74 °C, 85 °C and 97 °C was used for the calculation of the vapour pressure. The vapour pressure of the test material was 0.00082 Pa at 20 °C and 0.00119 Pa at 25 °C.

Under the conditions of the study, the vapour pressure of the test material was determined to be 0.00082 Pa at 20 °C and 0.00119 Pa at 25 °C.