Quaternary ammonium compounds, C18-22 (even numbered) alkyltrimethyl, chlorides; Docosyltrimethylammonium chloride; C18-22 TMAC

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Study period:

From July 18, 2017 to July 25, 2017

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

the results are considered unreliable; suspected to be influenced by trapped gas/impurities

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

not specified

GLP compliance:

yes

Type of method:

static method

Key result

Test no.:

#1

Temp.:

ca. 20 °C

Vapour pressure:

ca. 167 Pa

Remarks on result:

other: Run 1

Key result

Test no.:

#2

Temp.:

ca. 20 °C

Vapour pressure:

ca. 150 Pa

Remarks on result:

other: Run 2

Key result

Test no.:

#3

Temp.:

ca. 20 °C

Vapour pressure:

ca. 159 Pa

Remarks on result:

other: Mean of run 1 and run 2

Study test results

Temp/°C	Temp/K		P/mbar	**P/Pa
		Run 1
*20	293.15		1.67	167
30.0	303.15		3.7	370
40.0	313.15		8.7	870
50.1	323.25		17.0	1700
60.1	333.25		33.7	3370
		Run 2
*20	293.15		1.50	150
20.0	293.15		1.6	160
30.0	303.15		2.9	290
40.2	313.35		6.0	600
50.0	323.15		12.5	1250

*-Determinedbyextrapolation

**-Calculated

 

Comment

Run1–The sample was degassed for 15 h under vacuum

Run2–The sample was degassed for 18 h under vacuum

Conclusions:

Under study conditions, the vapor pressure of the test substance was determined to be 159 Pa at 20°C.

Executive summary:

A study was conducted to determine the vapor pressure of the test substance, according to the EU method A.4, in compliance with GLP, by static method. In the study, Run 1 (degassed, 15 h under vacuum) and Run 2 (degassed, 18 h under vacuum) test results were calculated to be 167 and 150 Pa at 20°C. Based on the study results, the mean vapor pressure was determined to be 159 Pa. Under study conditions, the vapor pressure of the test substance was determined to be 159 Pa at 20°C (Chilworth, 2017). However, the results are not considered to be reliable, given the structure/composition of the substance, together with the experimental vapoure pressure values of similar substances (i.e., other QAS member TMACs).

Description of key information

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

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C

Additional information

- Experimental VP = 159 Pa at 20 °C (static method); suspected to be influenced by trapped impurities.

- Weighted average QSAR based VP = 2.64E-09 Pa at 25°C (EPI Suite v.4.11) and 3.11E-04 Pa at 25°C (T.E.S.T. v4.2.1).The estimates for the major constituents were considered to be reliable with restrictions, as they do not completely fall within the applicability domain.

- Experimental VP of similar TMACs: VP values ranged from 2.64E-9 to <0.0058 Pa at25°C (Refer to the data matrix of the category justification)

Overall, based on the above information, the test substance, C18 -22 TMACcan be considered to have low volatility. However, in absence of a reliable experimental value, the higher QSAR based VP value of 3.11E-04Pa has been considered further for hazard/risk assessment as a conservative approach.