2-heptadecyl-1H-imidazole

Vapour pressure

Administrative data

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 - 19 Dec 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

boiling point

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Remarks:

In a differential scanning calorimetry, performed according to EU Method A.2, no boiling point could be determined up to a temperature of 500 °C at normal conditions. A boiling point can be estimated using the vapour pressure curve obtained in a study performed according to EU Method A.4.

Justification for type of information:

According to ECHA "Guidance on Information Requirements and Chemical Safety Assessment - Chapter R.7a: Endpoint specific guidance" (Version 6.0 July 2017):
"For high-boiling liquids or liquids which may decompose, auto-oxidize etc. before the boiling point at 101.3 kPa or more is reached, it is recommended to determine the boiling point either under inert gas or at reduced pressures, in order to derive the boiling point at reduced pressures from the vapour pressure curve."
"In such cases the boiling point under reduced pressure (down to 0.2 kPa) should be determined if possible without decomposition."

The vapour pressure curve equation, as obtained by a reliable study according to OECD Guideline 104, will be used to estimate the boiling point at reduced pressure.

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

See "Justification for type of information"

GLP compliance:

no

Type of method:

other: Extrapolation from the vapour pressure curve.

Key result

Boiling pt.:

ca. 278 °C

Atm. press.:

0.2 kPa

The boiling point at reduced pressure (0.2 kPa = 200 Pa) was calculated by means of the vapour pressure curve equation, to be:

T = -2590 / (log (200) - 7) = 551.18 K

BP = 551.18 - 273.15 = 278.03 °C

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Version / remarks:

May 30, 2008

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

2006

Deviations:

no

GLP compliance:

yes

Type of method:

effusion method: Knudsen cell

Test material

Test material information

1

Reference substance name:

2-heptadecyl-1H-imidazole

EC Number:

245-589-7

EC Name:

2-heptadecyl-1H-imidazole

Cas Number:

23328-87-2

Molecular formula:

C20H38N2

IUPAC Name:

2-heptadecyl-1H-imidazole

Results and discussion

Vapour pressure

Key result

Temp.:

20 °C

Vapour pressure:

0.013 Pa

Any other information on results incl. tables

Results of the analysis

The result of the thermogravimetric analysis for test item and the vapour pressure at 20 °C are given in the following table.

T [°C]	Δm [mg]	Δt [min]	T [K]	1/T [1/K]	Δm/Δt [kg/s]	Vapour pressure [Pa]	log p
33.9	0.0260	80	307.05	3.26E-03	5.42E-12	2.96E-02	-1.5280
40.0	0.0415	80	313.15	3.19E-03	8.65E-12	4.78E-02	-1.3207
46.4	0.0562	80	319.55	3.13E-03	1.17E-11	6.54E-02	-1.1846
53.2	0.0734	80	326.35	3.06E-03	1.53E-11	8.63E-02	-1.0641
60.3	0.1343	80	333.45	3.00E-03	2.80E-11	1.60E-01	-0.7970
67.7	0.1515	80	340.85	2.93E-03	3.16E-11	1.82E-01	-0.7399
39.7	0.0425	80	312.85	3.20E-03	8.85E-12	4.89E-02	-1.3105
46.3	0.0631	80	319.45	3.13E-03	1.31E-11	7.34E-02	-1.1344
53.2	0.1045	80	326.35	3.06E-03	2.18E-11	1.23E-01	-0.9106
60.7	0.1613	80	333.85	3.00E-03	3.36E-11	1.92E-01	-0.7172
68.1	0.1857	80	341.25	2.93E-03	3.87E-11	2.23E-01	-0.6513

Data in the tables are rounded values taken from Excel spreadsheets which will be archived together with the raw data. The use of Excel spreadsheets for calculations produces more accurate endpoints. These endpoints may slightly differ from the values derived by replacing the rounded values in the formulae given in the methods section.

Since the analysis was conducted under high vacuum conditions, the heat could be transferred only by radiation, this caused a consistent difference between the furnace temperature and the sample one and a considerable time for the system to reach equilibrium. The temperatures reported (registered by the thermocouple under the Knudsen cell) are hence different from the one set and the mass loss has been measured only in 80 minutes time interval within each isotherm, after the system had reached equilibrium.

 

Determination of the vapour pressure curve

y = mx + q	Parameter m (slope)	Parameter q (intercept)	Parameter R² (correlation)
	-2590	7	0.96146

 

Extrapolation of the vapour pressure at 20 °C

Extrapolation at 20°C	1/Temperature [1/K]	log p	Vapour pressure [Pa]
	0.00341	-1.8871	1.30E-2