N-(2-{[C16-18 (even numbered) alkanoyl]amino}ethyl)-N-(2-hydroxyethyl)[C16-18 (even numbered) alkylamide

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 July 2017 - 18 May 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Study was conducted in accordance with international guidelines and in accordance with GLP. Not all experimental validity criteria were met. The test item was determined to have a vapour pressure that was too low to achieve reliable and repeatable measurement. As a consequence statistical analysis was not possible. A worst case limit value, based on a measured data point and historical lab data, was determined and reported.

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Version / remarks:

Regulation (EC) 440/2008 of 30 May 2008

Deviations:

yes

Remarks:

Due to methodological limitations and the properties of the test item, only one vapour pressure value (at 25 °C) was determined.

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

23 March 2006

Deviations:

yes

Remarks:

Due to methodological limitations and the properties of the test item, only one vapour pressure value (at 25 °C) was determined.

GLP compliance:

yes (incl. QA statement)

Type of method:

effusion method: vapour pressure balance

Key result

Temp.:

25 °C

Vapour pressure:

< 0.01 Pa

Remarks on result:

other: Limit Value

Remarks:

See discussion.

Key result

Transition / decomposition:

no

Evaluation of Data:

The vapour pressure is related to the observed mass difference using Equation 1:

 

Equation 1:

V_p= (δm.g)/A

 

Where:

V_p = vapour pressure (Pa)

δm = mass difference (kg)

g = acceleration due to gravity (9.813 m s^-2)

A = area of the orifice (7.06858 x 10^-6m²)

 

 

Vapour pressure is related to temperature using Equation 2:

Log₁₀V_p= slope/T + intercept

 

Where

V_p = vapour pressure (Pa)

T = temperature (K)

 

A plot of Log10 V_p(Pa) versus reciprocal temperature (1/T(K)) therefore gives a straight-line graph.

 

The vapour pressure of the sample was measured over a range of temperatures to enable extrapolation to 298.15 K.

 

 

Results:

Recorded temperatures, mass differences and the resulting calculated values of vapour pressure are shown in the following tables:

 

Table 1:          Vapour Pressure Data, Run 7

Temperature	Temperature	Reciprocal Temperature	Mass Difference	Mass Difference	Vapour Pressure	Log10Vp
°C	K	K^-1	µg	kg	Pa
39	312.15	0.0032036	13.88	1.388 x 10^-8	0.0192690	-1.715141
40	313.15	0.0031934	9.58	9.580 x 10^-9	0.0132995	-1.876165
41	314.15	0.0031832	6.89	6.890 x 10^-9	0.0095651	-2.019311
42	315.15	0.0031731	7.49	7.490 x 10^-9	0.0103980	-1.983049
43	316.15	0.0031631	6.69	6.690 x 10^-9	0.0092874	-2.032104
44	317.15	0.0031531	8.69	8.690 x 10^-9	0.0120639	-1.918511
45	318.15	0.0031432	6.59	6.590 x 10^-9	0.0091486	-2.038645
46	319.15	0.0031333	8.59	8.590 x 10^-9	0.0119251	-1.923537
47	320.15	0.0031235	9.09	9.090 x 10^-9	0.0126192	-1.898966
48	321.15	0.0031138	8.39	8.390 x 10^-9	0.0116475	-1.933768
49	322.15	0.0031041	9.29	9.290 x 10^-9	0.0128969	-1.889515

No statistical analysis is given due to the nature of the plot.

 

 

Table 2:          Vapour Pressure Data, Run 8

Temperature	Temperature	Reciprocal Temperature	Mass Difference	Mass Difference	Vapour Pressure	Log10Vp
°C	K	K^-1	µg	kg	Pa
39	312.15	0.0032036	15.08	1.508 x 10^-8	0.0209349	-1.679129
40	313.15	0.0031934	8.39	8.390 x 10^-9	0.0116475	-1.933768
41	314.15	0.0031832	7.09	7.090 x 10^-9	0.0098427	-2.006884
42	315.15	0.0031731	7.29	7.290 x 10^-9	0.0101204	-1.994803
43	316.15	0.0031631	7.09	7.090 x 10^-9	0.0098427	-2.006884
44	317.15	0.0031531	6.29	6.290 x 10^-9	0.0087321	-2.058880
45	318.15	0.0031432	7.19	7.190 x 10^-9	0.0099816	-2.000801
46	319.15	0.0031333	7.89	7.890 x 10^-9	0.0109533	-1.960453
47	320.15	0.0031235	8.89	8.890 x 10^-9	0.0123416	-1.908629
48	321.15	0.0031138	7.29	7.290 x 10^-9	0.0101204	-1.994803
49	322.15	0.0031041	7.59	7.590 x 10^-9	0.0105369	-1.977289

No statistical analysis is given due to the nature of the plot.

 

 

Table 3:          Vapour Pressure Data, Run 9

Temperature	Temperature	Reciprocal Temperature	Mass Difference	Mass Difference	Vapour Pressure	Log10Vp
°C	K	K^-1	µg	Kg	Pa
39	312.15	0.0032036	14.78	1.478 x 10^-8	0.0205184	-1.687856
40	313.15	0.0031934	9.19	9.190 x 10^-9	0.0127581	-1.894215
41	314.15	0.0031832	7.19	7.190 x 10^-9	0.0099816	-2.000801
42	315.15	0.0031731	9.09	9.090 x 10^-9	0.0126192	-1.898966
43	316.15	0.0031631	7.89	7.890 x 10^-9	0.0109533	-1.960453
44	317.15	0.0031531	7.79	7.790 x 10^-9	0.0108145	-1.965993
45	318.15	0.0031432	7.99	7.990 x 10^-9	0.0110922	-1.954984
46	319.15	0.0031333	7.39	7.390 x 10^-9	0.0102592	-1.988886
47	320.15	0.0031235	8.19	8.190 x 10^-9	0.0113698	-1.944246
48	321.15	0.0031138	7.49	7.490 x 10^-9	0.0103980	-1.983049
49	322.15	0.0031041	7.59	7.590 x 10^-9	0.0105369	-1.977289

No statistical analysis is given due to the nature of the plot.

 

 

Table 4:          Vapour Pressure Data, Run 10

Temperature	Temperature	Reciprocal Temperature	Mass Difference	Mass Difference	Vapour Pressure	Log10Vp
°C	K	K^-1	µg	kg	Pa
39	312.15	0.0032036	8.49	8.490 x 10^-9	0.0117863	-1.928623
40	313.15	0.0031934	10.38	1.038 x 10^-8	0.0144101	-1.841333
41	314.15	0.0031832	6.99	6.990 x 10^-9	0.0097039	-2.013053
42	315.15	0.0031731	6.59	6.590 x 10^-9	0.0091486	-2.038645
43	316.15	0.0031631	6.09	6.090 x 10^-9	0.0084545	-2.072913
44	317.15	0.0031531	6.49	6.490 x 10^-9	0.0090098	-2.045286
45	318.15	0.0031432	6.99	6.990 x 10^-9	0.0097039	-2.013053
46	319.15	0.0031333	6.19	6.190 x 10^-9	0.0085933	-2.065840
47	320.15	0.0031235	7.09	7.090 x 10^-9	0.0098427	-2.006884
48	321.15	0.0031138	7.19	7.190 x 10^-9	0.0099816	-2.000801
49	322.15	0.0031041	8.59	8.590 x 10^-9	0.0119251	-1.923537

No statistical analysis is given due to the nature of the plot.

 

 

Discussion:

The appearance of the test item did not change under the conditions used in the determination.

 

No statistical analyses were performed because the balance readings were too low and variable for a line of best fit to have any meaning. Instead it was considered more appropriate to impose a regression slope on a chosen data point to provide an estimate of the maximum value for the vapour pressure at 25 ºC. Runs 7 to 10 have been included to demonstrate the behaviour of the test item under the test conditions; Runs 1 to 6 were similar and no statistical analysis could be obtained due to the nature of these plots.

 

Run 10 was chosen because the sample had been under vacuum for the longest period prior to this run and so degassing would have been the most complete. The reading at 40 ºC (313 K) was chosen because this is the data point which gives the highest estimated vapour pressure at any given temperature when a slope of –1000 K is imposed upon it.

 

The value of –1000 K is an in-house value and is the shallowest slope observed whilst determining the vapour pressure on a wide range of samples using the vapour pressure balance method. Extrapolation to 25 ºC gave a vapour pressure of 9.95 x 10-3 Pa which has been taken as a maximum for this substance.

 

The results may represent rounded values obtained by calculations based on the exact raw data.

 

Conclusion:

The vapour pressure of the test item has been determined to be less than 1.0 x 10^-2Pa at 25°C.

Conclusions:

The vapour pressure of the test item has been determined to be less than 1.0 x 10-2Pa at 25°C.

Executive summary:

EU Method A.4. – The vapour pressure of the test item was sought using the vapour pressure balance method.  The procedure employed was designed to be compatible with Method A.4. Vapour Pressure of Commission Regulation (EC) No 440/2008 of 30 May 2008.

 

The test item was subject to a sequence of runs to determine vapour pressure. A sample of test item was held under vacuum for approximately 20 hours. Temperature and mass differential readings were measured across a temperature range of39 and 49°C following the outcome of a preliminary test.  Values measured across this temperature range showed a poor linear response.

 

In light of the poor linear response of the test item to experimental conditions, no statistical analyses were performed because the readings were too variable for a line of best fit to have any meaning. It was considered more appropriate to impose a regression slope on a chosen data point to provide an estimate of the maximum value for the vapour pressure at 25°C. This methodology was applied to a reading at 40°C (313 K) obtained during the final test run. This value was chosen as the test item had been under vacuum for the longest period prior to this run and so degassing would have been the most complete. Further this temperature resulted in the highest estimated vapour pressure at any given temperature when a slope of –1000 K is imposed upon it. The value of –1000 K is an in-house laboratory value. It is the shallowest slope observed whilst determining the vapour pressure on a wide range of samples using the vapour pressure balance method. Extrapolation to 25°C gave a vapour pressure of 9.95 x 10^-3Pa which has been taken as a maximum for this substance.

 

A vapour pressure limit value of the test item has been determined to be 9.95 x 10-3 Pa at 25 °C.

Description of key information

Vapour Pressure: < 1.0 x 10^-2 Pa at 25 ºC.; EU Method A.4.; R. Butler (2018)

Key value for chemical safety assessment

Vapour pressure:

0.01 Pa

at the temperature of:

25 °C

Additional information

EU Method A.4. – The vapour pressure of the test item was sought using the vapour pressure balance method.  The procedure employed was designed to be compatible with Method A.4. Vapour Pressure of Commission Regulation (EC) No 440/2008 of 30 May 2008.

 

The test item was subject to a sequence of runs to determine vapour pressure. A sample of test item was held under vacuum for approximately 20 hours. Temperature and mass differential readings were measured across a temperature range of 39 and 49°C following the outcome of a preliminary test.  Values measured across this temperature range showed a poor linear response.

 

In light of the poor linear response of the test item to experimental conditions, no statistical analyses were performed because the readings were too variable for a line of best fit to have any meaning. It was considered more appropriate to impose a regression slope on a chosen data point to provide an estimate of the maximum value for the vapour pressure at 25°C. This methodology was applied to a reading at 40°C (313 K) obtained during the final test run. This value was chosen as the test item had been under vacuum for the longest period prior to this run and so degassing would have been the most complete. Further this temperature resulted in the highest estimated vapour pressure at any given temperature when a slope of –1000 K is imposed upon it. The value of –1000 K is an in-house laboratory value. It is the shallowest slope observed whilst determining the vapour pressure on a wide range of samples using the vapour pressure balance method. Extrapolation to 25°C gave a vapour pressure of 9.95 x 10^-3Pa which has been taken as a maximum for this substance.

 

A vapour pressure limit value of the test item has been determined to be < 1.0 x 10 ^-2 Pa at 25 °C.