Octadecanoic acid, reaction products with 2-amino-2-methyl-1-propanol

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 September 15, 2017 to December 18, 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study results suspected to be influenced by trapped gases/impurities

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

not specified

GLP compliance:

yes

Type of method:

static method

Key result

Test no.:

#1

Temp.:

ca. 20 °C

Vapour pressure:

ca. 3.7 Pa

Remarks on result:

other: Mean of run 3 and 4

Full test results

Temp / °C	Temp / K	P / mbar		P / Pa
Run 1
20	293.15		0.51	51
20.0	293.15		0.2824	28.24
30.2	303.35		1.4	140
40.0	313.15		3.6	360
50.0	323.15		3.2	320
60.0	333.15		3.4	340
Run 2
20	293.15		0.30	30
20.0	293.15		0.1683	16.83
30.0	303.15		0.7466	74.66
40.0	313.15		2.1	210
50.0	323.15		1.9	190
60.6	333.75		1.8	180
Run 3
20	293.15		0.0319	3.19
Run 4
20	293.15		0.0413	4.13

Comment

Run1 : Sample ground into a powder. 10.4 g test substance degassed: 16 h, Starting vacuum pressure: 0.0010 mbar. Sample melted at approximately 45°C and became a milky colour suspension.

Run2 : Sample ground into a powder. 11 g test substance degassed: 19 h, Starting vacuum pressure: 0.0011 mbar. Sample melts at approximately 45°C and became a milky colour suspension.

Run3 : Sample ground into a powder. 9.4 g test substance degassed: 26 h, Starting vacuum pressure: 0.0008 mbar.

Run4 : Sample ground into a powder. 9.4 g test substance degassed: 96 h, Starting vacuum pressure: 0.0007 mbar.

 

The results from runs 1 and 2 indicated a phase change at about 40°C. Some variability was noted in the values obtained at 20°C for runs 1 and 2. Two additional determinations were made at 20°C. Both these runs had increased degassing periods and gave similar results. It is the mean of the last two determinations that has been reported as the result.

Conclusions:

Under study conditions, the vapour pressure of the test substance was determined to be 3.7 Pa at 20°C.

Executive summary:

A study was conducted to determine the vapour pressure of the test substance, C16 -18 AMP, using the static method, according to EU Method A.4, static method, in compliance with GLP. In the study, the results from runs 1 and 2 indicated a phase change at about 40°C. Some variability was noted in the values obtained at 20°C for runs 1 and 2. Two additional determinations were made at 20°C with increased degassing periods and which gave similar results. The mean of the last two determinations, 3.7 Pa has been reported as a result by study author. Under study conditions, the vapour pressure of the test substance was determined to be 3.7 Pa at 20°C (Chilworth, 2017). The study results are suspected to be influenced by trapped gas/impurities.

Description of key information

The vapour pressure of the test substance was determined experimentally using the static method, according to EU Method A.4, (Chilworth, 2017) as well as using the QSAR models, EPI Suite and TEST (US EPA, 2018).

Key value for chemical safety assessment

Vapour pressure:

3.7 Pa

at the temperature of:

20 °C

Additional information

- Experimental VP = 3.7 Pa at 20 °C (static method); study results are suspected to be influenced by trapped gas/impurities.

- Weighted average QSAR based VP = 0.00179 Pa at 25°C (EPI Suite v.4.11) and 0.000208 Pa at 25°C (T.E.S.T. v4.2.1). The estimates for the major constituents are considered to be reliable with restrictions, as they do not completely fall within of the applicability domain.

- Experimental VP of structurally similar substance, Oleamide MIPA: 2.42E-6 Pa at 25°C (using gas saturation method).

Overall, based on the above information, the test substance can be considered to have low volatility. However, the higher VP value of 3.7 Pa has been considered further for hazard/risk assessment as a conservative approach.